Cognitive Neuroscience Final Exam
Key Concepts in Attention
Characteristics/Quality of Attention -limited capacity -selective Deployment of Attention -overt versus covert attention -voluntary = endogenous cueing paradigms -reflexive = exogenous cueing paradigms Attention improves processing speed and makes it more accurate
The Cocktail Party Effect in the Lab Cherry (1953)
DICHOTIC LISTENING Participants could not report any detail from the non-attended ear Some information in non-attended stream can capture attention
Results reported by Cherry (1953) from the _______ task provided initial support for the ________ model, which says that irrelevant input is filtered out before perceptual processing is complete.
Dichotic listening/ early selection
What is the Flanker Task meant to assess?
Ability to suppress responses that are incongruent with a certain context
Cognitive Control and Addiction response inhibition
Abnormal PFC function may contribute to addictive behaviors = general problems with inhibition Participants Cocaine Addicts -button press when sequentially presented letters are different; withhold response when they are the same -respond more often on "no-go" trials -hypoactivation in medial frontal cortex
What part of the brain is known for being the "monitoring system" of cognitive control?
Anterior Cingulate Cortex
Which region in the PFC is linked to anticipation of conflict and error avoidance?
Anterior Cingulate Cortex
Feature Attention
As our own experience tells us, we have learned that selectively attending to spatial locations, either voluntarily or reflexively, leads to changes in our ability to detect and respond to stimuli in the sensory world, and our improved detection is promoted by changes in neural activity in the visual cortex They compared spatial attention and feature attention in a voluntary cuing paradigm During the selective-attention condition, participants were instructed to compare the two arrays to determine whether a change had occurred to a pre-specified stimulus dimension During the divided-attention condition, participants were instructed to detect a change in any of the three stimulus dimensions These findings provide additional support for the idea that selective attention, in modality-specific cortical areas, alters the perceptual processing of inputs before the completion of feature analysis This difference does not indicate that spatial attention always drives our attention, because if one does not know where a stimulus will appear but does know which features are relevant, as during visual search, feature attention may provide the first signal that then triggers spatial attention to focus on a location
Cognitive Control Requires Working Memory
As we learned in Chapter 9, working memory, a type of short-term memory, is the transient representation of task-relevant information—what Patricia Goldman-Rakic called the "blackboard of the mind." The term working memory refers to the temporary maintenance of this information, providing an interface that links perception, long-term memory, and action, thus enabling goal-oriented behavior and decision making This process requires integrating current perceptual information with stored knowledge from long-term memory
How Does the Medial Frontal Cortex Monitor Processing in Cognitive Control Networks?
As with much of the frontal cortex, the medial frontal cortex exhibits extensive connectivity with much of the brain We will now review some hypotheses that have been proposed to account for the functional role of the medial frontal cortex in cognitive control ATTENTIONAL HIERARCHY HYPOTHESIS -An early hypothesis centered on the idea that the medial frontal cortex should be conceptualized as part of an attentional hierarchy -If the target noun is apple, then possible responses are "eat," "throw," "peel," or "juggle," and the participant must select among these alternatives -In a sense, the hierarchical attention model is reminiscent of the homunculus problem: To explain control, we postulate a controller without describing how the controller is controlled ERROR DETECTION HYPOTHESIS -Concern about the attentional hierarchy hypothesis inspired researchers to consider other models of how medial frontal cortex might be involved in monitoring behavior -This signal, referred to as the error-related negativity when time-locked to the response, and the feedback-related negativity when time-locked to feedback, has been localized to the anterior cingulate -In most situations, we are surprised when we make errors RESPONSE CONFLICT HYPOTHESIS -Jonathan Cohen and his colleagues have hypothesized that a key function of the medial frontal cortex is to evaluate response conflict -Activation in the LPFC was highly correlated with activation in the ACC on the preceding trial -These findings demonstrate how a monitoring system might produce moment-to-moment adjustments in processing at the neuronal level to support goal-oriented behavior. ACC FUNCTION IS STILL UP IN THE AIR -The response conflict hypothesis remains a work in progress, and the literature suggests some problems that need to be addressed -Nonetheless, they offer an encouraging example of how even the most advanced of our cognitive competencies can be subject to rigorous experimental investigation, given the many tools of cognitive neuroscience
Frontal Lobe Lesions planning and goal-directed behavior
Behavior is not dictated solely by immediate experience, we establish long-term goals & come up with plans to execute them PFC Damage = Inability to Form Coherent Plan of Action Six years after removal of a large bilateral orbitofrontal meningioma, an accountant with high IQ, and good performance on several neuropsychological tests, was grossly impaired in his ability to organize his life -relatively simple activities would take hours to go out to dinner required that he consider the seating plan, menu, atmosphere and management of each restaurant and he might even drive to see how busy each of them was, but was still unable to come to a decision -dismissed from several jobs despite having a perfectly good skill set -bankrupt / 2 divorces 3 Patients with Frontal Lesions -normal performance on neuropsychological tests Saturday Morning Errand Task -Purchase Items -Keep a scheduled appointment -Collect 4 pieces of information NOT MEMORY Participants kept list of required items and instructions -Instructions were specific and reiterated by each patientWhat Happened? -All 3 patients were severely impaired on this task -"Case 3 broke a rule because when in the shop she found it did not have a soap she especially liked; other cheap soap which would have been at least as adequate for the task was available" -One patient walked out of a shop where he had acquired yesterday's newspaper without paying for it He had "assumed that because a previous day's newspaper was generally worthless he could have one without paying" -Shallice and Burgess Performance of this multi-dimensional task is severely impaired by frontal damage; may be related to failures in planning, setting boundaries, or evaluating the goal
Frontal Lobe Lesions utilization behavior
Behavior is stimulus-driven and guided by prototypical responses; no situation-specific inhibition or flexible execution of these behaviors
Goal-Oriented Behavior
Behavior that is based on an "action-outcome" relationship.
Habit
Behavior that is stimulus-driven and automatic - not controlled by reward or volition.
According to the ________ model of visual attention, two (or more) stimuli compete to control neuronal firing when they both fall in the receptive field of that cell. It is proposed that competition is ________ at higher levels of the visual processing hierarchy where receptive field size is ________.
Biased competition/ greater/ LARGER
The Bálint's syndrome is caused by which of the following?
Bilateral damage to regions of the posterior parietal and occipital cortex.
In a neuropsychological test of neglect, patients with left-sided neglect tend to _______.
Bisect the lines to the right of the midline.
reflexive attention
Bottom-up, stimulus-driven process in which a sensory event captures our attention
Frontal Eye Fields
Brain area that is a driver of saccades and is also part of the attentional control network.
The ACC Remains a Mystery
Brown and Braver -Activation in ACC is more closely linked to anticipation of errors than to commission of errors = anticipation of conflict and error avoidance Grinband et al. -ACC is sensitive to time on task, even when the task itself is simple and without conflict -Patients with medial frontal lesions do not show impairments on tasks that require conflict monitoring = abnormally low levels of arousal in the face of physical and mental challenges
Inhibition of Return
Following capture, this is the slow response to targets that appear in an exogenously cued location.
Patients with ______ lobe lesions can continue to give the same response, despite being told it's incorrect, this is called _______.
Frontal / Perseveration
______ drives attention to spatial locations while ______ drives attention to feature selection.
Frontal Eye Fields / Inferior Frontal Junction
Which term best fits the description below?:Both attended and ignored input are registered by sensory and perceptual processes. Information is processed by perceptual reach or semantic meaning analysis. Then, selection happens.
Late selection Model
Exogenous cueing task structure
Instruction: Make a Button Press as Quickly as Possible when the Target Appears
In a task with two rectangles, a cue illuminated one end of one rectangle. Then a target appeared where the cue was (valid), at the other end of the cued rectangle (invalid - same object) or within the non-cued rectangle at the same end as the cue (invalid - different object). Which is NOT an accurate statement of the results?
Invalid - same object response time was faster than that for the invalid -different object condition due to inhibition of return.
Which of the following statements regarding Error-related Negativity is False?
It can be generated without awareness.
Visual stimuli are presented to the left and right of a central fixation cross. A cue indicates that you should attend to the stimulus on the left. In this example, you would expect to see increased activity in the ________ hemisphere and the ________ is the earliest structure in the visual processing pathway where you'd expect to see this effect.
Right hemisphere/ LATERAL GENICULATE NUCLEUS
Attention to Features and Objects
Objects can be the targets of attention -Face & House Superimposed in Space -One Static / One Dynamic -Activity increases in specialized processors when the preferred stimulus is attended -Objects come along for free when the are associated with the attended feature
What kind of attentional processing was examined in this study - feature-based attention, spatial attention, object-based attention?
Objects can be the targets of attention!
endogenous attention
Occurs when a person consciously decides to scan the environment to find a specific stimulus or monitor what is happening Can also occur for auditory stimuli
Goal Planning: Staying on Task
Once humans choose a goal, we have to figure out how to accomplish it The simplest task manipulated response competition by varying the number of possible finger responses to a series of colored squares presented one at a time; the response was based on the color of the square, and there could be one, two, or four different responses Complex actions require that we maintain our current goal, focus on the information that is relevant to achieving that goal, ignore irrelevant information, and, when appropriate, shift from one subgoal to another in a coordinated manner Successful execution of an action plan involves three components: (1) identifying the goal and developing subgoals (2) anticipating consequences when choosing among goals (3) determining what is required to achieve the goals Goal-oriented behavior requires the retrieval and selection of task-relevant information -The prefrontal cortex can be conceptualized as a dynamic filtering mechanism through which the task-relevant information is activated and maintained in working memory Cognitive control is also essential when we need to maintain multiple goals at the same time, especially when those goals are unrelated -With practice, the brain develops connectivity patterns that enable people to efficiently shift between different goals Through the selection of task-relevant information, the prefrontal cortex helps make action selection more efficient -This benefit of using experience to guide action selection may also come at a cost in terms of considering novel ways to act, given a specific situation
The Medial Frontal Cortex as a Monitoring System
One might expect the task of a monitoring system to be like that of a supervisor, keeping an eye on the over-all flow of activity, ready to step in whenever a problem arises The last 30 years have witnessed burgeoning interest in the medial frontal cortex, and in particular the anterior cingulate cortex, as a critical component of a monitoring system The functional roles ascribed to most cortical regions were inspired by behavioral problems associated with neurological disorders; damage to the cingulate, either in animal models or in the few clinical reports with humans, was associated with akinetic mutism, a disorder characterized by minimal movement, including the absence of speech The activations were clustered in the anterior cingulate regions but also extended into BA8 and BA6; thus, we refer to this entire region as medial frontal cortex
You are working with a patient and have asked him to draw a clock. When he's done, all of the numbers are on the right side of the clock face. Based on this observation your diagnosis is ________; to confirm, you administer a ________ test, which is also used to diagnose this condition.
SPATIAL NEGLECT/ LINE BISECTION
Dorsal Attention Network control of voluntary attention
Same network of structures regardless of cue direction None of these regions were recruited in sensory control tasks Priming of sensory sites where targets of attention will be processed / preparatory upregulation of signaling in these regions
Ventral Attention Network
Set of brain structures implicated in directing attention to salient or unexpected stimulus information.
Dynamic Filtering Model of PFC Function
Shimamura -Task-relevant information must be selected to achieve a particular goal -Lateral PFC actively represents currently relevant cognitive content, but also permits selection of task-relevant information from working memory for more detailed evaluation -Task-relevant information must be selected to achieve a particular goal -Lateral PFC actively represents currently relevant cognitive content, but also permits selection of task-relevant information from working memory for more detailed evaluation STROOP TASK Individuals with frontal lobe lesions are more likely to read the words = problem with selecting task-relevant representations
Inhibitory Control
Process important for selective attention in which irrelevant input is down-regulated or attenuated.
Oscillatory Coherence
Proposed mechanism for attentional control characterized by synchronous firing between brain areas.
Research has shown that cocaine addicts have a general problem with _______, a behavioral outcome that is associated with reduced activation in the ______.
RESPONSE INHIBITION/ medial frontal cortex
What was the dependent variable in Posner's (1980) endogenous cueing test?
Reaction Time
What major view of ACC (medial frontal cortex) function was challenged by the results of the time estimation task?
Reduced activity ~30 seconds before an error was made. Increased default mode activity (self-referential thought) prior to errors
While out at night you hear a twig snap and shift your attention the direction if the snap, this is an example of...
Reflexive Attention
Working Memory
Temporary representation of goal-relevant information Monkeys with lateral PFC lesions are impaired on the Working Memory Task Animal must continue to represent the unseen location during the delay No explicit cues Location varies randomly from trial to trial; animals must remember the currently baited food well Not associative learning Presentation of the two visual cues triggers long-term associative recall and supports the correct response Measures the ability of the monkey to retain long-term rules Fuster & Alexander -Is there evidence for active maintenance in the lateral PFC? -Is this maintenance signal generic or stimulus specific? -Task requires retention of object- and location-specific information -Some cells respond to preferred object-location combinations -What exactly is being represented? -Memory or motor response mechanism? -Sustained delay-period response is not evident during passive viewing or in untrained animals who have not yet learned to use the cue to guide behavior Rao, et al. -is lateral PFC the storehouse of remembered content? -No - frontal lobe damage does not result in compromised long-term memory -What exactly does the lateral PFC do?
Error Detection Hypothesis
The Flanker Task Error-related Negativity -Large evoked response sensitive to incorrect responses -Absent without awareness -Magnitude correlated with intensity of incorrect response -Localized to Anterior Cingulate Functional Significance: Error Detection = Cognitive Control Alert Lateral PFC to reactivate goal in WM Typically, show increases and decreases subsequent to stimulus onset Reduced activity ~30 seconds before an error was made Increased default mode activity prior to errors
Alternative Views of Dopamine Activity
The RPE story elegantly accounts for the role of dopaminergic cells in reinforcement and learning, but there remain viable alternative hypotheses One subset of DA neurons responded in terms of valence A greater number of DA neurons, however, were excited by salience—the increased likelihood of any reinforcement, independent of whether it was a reward or a punishment, and especially when it was unpredictable These observations bring us back to how frontal lobe control systems are at work in both decision-making and goal-oriented behavior
Reflexive Attention
The ability of a sensory event to capture our attention Also known as bottom-up or stimulus-driven attention
Overt Attention
The act of orienting to (e.g., looking at) an attended object or spatial location.
What is selective attention?
The allocation of attention among relevant inputs, thoughts, and actions while simultaneously ignoring irrelevant or distracting ones.
What happens to the amplitude of the P1 ERP waveform when attention is at the target location?
The amplitude increases.
exogenous cuing
The control of attention by external stimuli and not by internal voluntary control
feedback-related negativity
The feedback-related negativity has been found to be sensitive to negative feedback as well as negative prediction error, such that the FRN is larger for outcomes that are worse than expected The present study examined prediction errors in both appetitive and aversive conditions
frontal pole
The most anterior part of the prefrontal cortex, including area 10 and parts of area 9 This region is hypothesized to play a critical role in the hierarchical representation of action goals
Investigators tracked the eye movements of individuals with unilateral spatial neglect during a visual search task and found that...
The participants did not move their eyes towards the left visual field at rest or during the task.
Recall the study conducted with cognitive control and addiction. Cocaine addicts who had been sober for 18 hours were tested on inhibition response. What were the results of this study?
The participants had trouble withholding a button press on the "no go" trials.
Prefrontal Cortex Is Necessary for Working Memory but Not Associative Memory
The prefrontal cortex appears to be an important interface between current perceptual information and stored knowledge, and thus constitutes a major component of the working memory system Its importance in working memory was first demonstrated in studies where animals with prefrontal lesions performed a variety of delayed-response tasks Evolutionarily significant differences between species may be found in the capacity of the working memory, how long information can be maintained in working memory, and the ability to maintain attention
Organizational Principles of Prefrontal Cortex
The prefrontal cortex covers a lot of brain territory Jessica Cohen and Mark D'Esposito constructed connectivity maps to show the cortical networks at work during rest, during a simple motor task, and during an n-back task In particular, during the demanding n-back task, the dorsolateral PFC network expands, showing marked connectivity with parietal regions and areas in the ventral visual pathway Not only does the cognitive control network become more expansive during the n-back task, but the connection strength between networks increases, with more voxels now classified as connector hubs The working memory demands of the n-back task require maintaining the goal, staying on task, and keeping track of the visual stimuli Thus, with the motor task, segregation of distinct networks is increased; in contrast, the more cognitively demanding n-back task requires integration across networks
How do individuals with frontal lobe lesions respond to the Stroop Task?
They are more likely to read the word.
inhibition of return
a slowing of reaction time associated with going back to a previously attended location
late selection
a theory of attention in which all incoming information is processed up to the level of meaning before being selected for further processing
early selection
a theory of attention in which information is selected according to perceptual attributes
Monitoring & Goal Maintenance Coordination
Lateral PFC = Online Representation of Goal Medial PFC = Monitor Progress to Achieve Goal High Conflict Trials: 1. ACC Activity HIGH that Trial 2. PFC Activity HIGH next Trial Second Trial is Incongruent: 1. Lower = preceded by incong 2.Higher = preceded by cong Difficult Trials Remind Participants to Stay on Task
The _______ is critical for active, online retention of stimulus materials. Activity in this brain region is _______ when working memory load is high (e.g., 4 faces) as compared to when it's low (e.g., 1 face).
Lateral PFC/ GREATER
Patients with damage to the _____ had the most difficulty picking a single verb to correspond to an object when selection demands were high in the Thompson-Schill (1998) task.
Left Inferior Frontal Gyrus
When instructions require you to process and maintain faces but ignore scenes, activity differences in PPA ________, this inhibitory effect _______ in older adults.
decrease / is reduced
neglect
fail to care for properly
Prefrontal Cortex the site of cognitive control
frontal cortex larger in primates -humans = expansion of white matter tracts•numerous, reciprocal connections with cortical and subcortical sites Goal-Oriented Behavior Monitoring
There are two fundamental types of actions;_______ actions are based on the assessment of an expected reward or value and the knowledge that there is a causal link between the action and the reward. In contrast,______ actions are considered automatic, and stimulus driven because the action is no longer under the control of the reward.
goal orientated/habitual
Cognitive control refers to the collection of processes that permit the execution of ______ behavior
goal oriented
When the TRN (thalamic reticular nucleus) neurons are active, the signal is ________ and the result is a(n) ________.
inhibitory; reduction in signal transmission to Visual Cortex when visual inputs are to be ignored
lateral prefrontal cortex
language comprehension and word analysis
This brain region exhibits increased activation as the n-back task difficulty is increased, indicating this region is critical for cognitive manipulation.
lateral prefrontal cortex
secondary reinforcers
learned reinforcers, such as money, that develop their reinforcing properties because of their association with primary reinforcers
PFC as the Top in Top-Down Control
rTMS or Sham Before Behavioral Testing Behavioral Performance: Color Task P1 ERP Component Modulation -Effects of rTMS greater for participants with stronger functional connectivity between IFJ and specialized sensory processing sites -Causal role for PFC in top-down control of sensory processors
superior colliculus
receives visual sensory input
Which of the following is not an example of goal-driven (top-down) control?
suddenly turning your head to the direction of a loud dog bark
The amplitude of the P1 ERP waveform is greater when _______.
targets are presented in a cued location
monitoring
the act of observing something
goal-oriented behavior
the behavior of market participants interested in fulfilling their own, personal goals
endogenous cuing
the control of attention by internal stimuli under voluntary control
dorsal attention network
top down, endogenous attentional control
The attention network that is engaged when physically salient or unexpected events occur (i.e., bottom-up attention) is the _______?
ventral attention network
unilateral spatial neglect
when a person ignores part of his or her visual field
What were the results? And, what do these results tell us about how brain activity is regulated by attention?
•Activity increases in specialized processors when the preferred stimulus (face, house, movement) is attended •Objects come along for free when the are associated with the attended feature
Briefly, how did the task work and what neuroscience method was used?
•Face & House Superimposed in Space •One Static / One Dynamic
What was the reported result of the MEG Investigation: Color & Motion?
•activity differences 100ms after stimulus onset •slower for feature attention (V3, V4) than for spatial attention (LGN and V1)
overt attention
shifting attention from one place to another by moving the eyes
What brain structure is responsible for filtering out irrelevant/suboptimal information?
Inferior Frontal Gyrus
A study used active video game training to improve cognition in older adults. The results revealed that those in a (A) training condition showed a boost in the magnitude of (B) power in EEG recording.
(A) = Multitask (B) = frontaltheta
Summary of Attention part 1
-Attention permits prioritization of a limited amount of information for focused processing -Attention can be deployed voluntarily or reflexively -Targets of attention can be prioritized based on their spatial locations, visual features, and whole objects -Visual search may be based on a single, distinctive feature or the conjunction of features; focused attention is required for binding = Feature Integration Theory
Working Memory the blackboard of the mind
-PFC interacts with other neural sites to keep memory representations active -Information maintained by PFC while behaviorally relevantIs lateral PFC activity modulated by WM load? How do PFC and FFA respond when faces are active in WM? -Activity differences in Lateral PFC increase w/ WM load -Lateral PFC / FFA connectivity permits active retention of faces in WM for comparison with a test stimulus -Requires maintenance and manipulation -Lateral PFC activity increases with difficulty; greater demands on updating/manipulation
Frontal Lobe Lesions failures in cognitive control
-no impairment on conventional neuropsychological tests -normal range IQ scores -performance on tests of long-term memory is not compromised BUT closer evaluation of performance on task that require goal-directed behavior is revealing -perseveration continue to give the same response, despite being told it's incorrect -apathetic, distractible, impulsive•inability to plan and make decisions -engage in inappropriate social behavior = Social Cognition
Which of the following statements is true about video games and cognitive control?
15 hours of Medal of Honor training improved performance on a cognitive control task when compared to Tetris and no training.
The Wisconsin Card sorting task had ______ experimental conditions and the sorting rule changes after _____ successful trials.
3 / 10
Attention
A PATIENT WHO suffered a severe stroke several weeks ago sits with his wife as she talks with his neurologist We conclude with a discussion of the brain networks used for attentional control
Cognitive Control
A SEASONED NEUROLOGIST was caught by surprise when his new patient, W.R., reported his main symptom quite simply: "I have lost my ego." Planning how to attain it and then sticking with the plan are also complicated affairs involving different cognitive control processes, which we examine in the final sections of this chapter
Is It Worth It? Value and Decision Making
A cornerstone idea in economic models of decision making is that before we make a decision, we first compute the value of each option and then compare the different values in some way Although many lottery players dream of winning the million-dollar prize, some may forgo a chance at the big money and buy a ticket with a maximum payoff of a hundred dollars, knowing that their odds of winning are much higher COMPONENTS OF VALUE -To figure out the neural processes involved in decision making, we need to understand how the brain computes value and processes rewards -Some rewards, such as food, water, or sex, are primary reinforcers: They have a direct benefit for survival fitness -Their value, or our response to these reinforcers, is, to some extent, hardwired in our genetic code -Secondary reinforcers, such as money and status, are rewards that have no intrinsic value themselves, but become rewarding through their association with other forms of reinforcement -Establishing the value of these options requires considering several factors, all of which contribute to the representation of value: Payoff -What kind of reward do the options off er, and how large is the reward? -Probability -Effort or cost -One form of cost that has been widely studied is temporal discounting -Context -Preference -What seems irrational thinking by another individual might not be, if we could peek into that person's up-to-date value representation of the current choices REPRESENTATION OF VALUE -How and where is value represented in the brain? -Besides comparing cellular activity in different locations, the experimenters manipulated cost, probability, and payoff -A classic finding in behavioral economics, temporal discounting, is the observation that the value of a reward is reduced when we have to wait to receive that reward -In contrast, fMRI studies generally provide relative answers, asking whether an area is more responsive to variation in one dimension compared to another dimension
N-Back Task
A laboratory test that is used to examine working memory and is associated with activity in lateral PFC.
Reward Prediction Error
A learning signal that updates value information based on expectations and outcomes.
Neglect
A patient with neglect may notice you more easily when you are on her right side, comb her hair only on the right, eat from only the right half of her plate, and read only the right-hand page of a book Unilateral spatial neglect, or simply neglect, is quite common The neglect patients show a pattern of eye movements biased in the direction of the right visual field, while those without neglect search the entire array, moving their eyes equally to the left and right NEUROPSYCHOLOGICAL TESTS OF NEGLECT -Neuropsychological tests are used to diagnose neglect -Furthermore, when imagining themselves standing across the piazza, facing toward the Duomo, they reported items from visual memory that they had previously neglected, and they neglected the side of the piazza that they had just described -The key point in Bisiach and Luzzatti's experiment is that the patients' neglect could not be attributed to a failure of memory, but rather indicated that attention to parts of the recalled images was biased EXTINCTION -Visual field testing shows that neglect patients are not blind in their left visual field: They are able to detect stimuli normally when those stimuli are salient and presented in isolation -This result is known as extinction, because the presence of the competing stimulus in the ipsilateral hemifield prevents the patient from detecting the contralesional stimulus.he slightest distraction and I won't see it"
Medial Frontal Cortex
A proposed site of "conflict monitoring" in the brain.
habit
A repetitive act performed by a particular individual
P1
A sensory-evoked ERP component that is sensitive to whether or not a visual stimulus is attended.
response conflict
A situation in which more than one response is activated, usually because of some ambiguity in the stimulus information It has been hypothesized that the anterior cingulate monitors the level of response conflict and modulates processing in active systems when conflict is high
Fusiform Face Area
A specialized part of the cortex that can be categorized as a "site" of attention.
visual search
A task in which participants are asked to determine whether a specified target is present within a field of stimuli
delayed-response tasks
A task in which the correct response must be produced after a delay period of several seconds Such tasks require the operation of working memory because the animal or person must maintain a record of the stimulus information during the delay period
extinction
A term that typically describes a species that no longer has any known living individuals
thalamic reticular nucleus
A thin layer of neurons surrounding the nuclei of the thalamus, which receives inputs from the cortex and subcortical structures and sends projections to the thalamic relay nuclei
Physiological Correlates of Working Memory
A working memory system requires a mechanism to access stored information and keep that information active With n-back tasks, it is not sufficient simply to maintain a representation of recently presented items; the working memory buffer must be updated continually to keep track of what the current stimulus must be compared to Tasks such as n-back tasks require both the maintenance and the manipulation of information in working memory Activation in the LPFC increases as n-back task difficulty is increased—a response consistent with the idea that this region is critical for the manipulation operation
action-outcome decisions
Action-outcome and stimulus-response processes that are two forms of instrumental conditioning that are important components of decision making and action selection The former adapts its response according to the outcome while the latter is insensitive to the outcome An unsolved question is how these two processes emerge, cooperate and interact inside the brain in order to issue a unique behavioral answer Here we propose a model of the interaction between the cortex, the basal ganglia and the thalamus based on a dual competition We hypothesize that the striatum, the subthalamic nucleus, the internal pallidum, the thalamus, and the cortex are involved in closed feedback loops through the hyperdirect and direct pathways These loops support a competition process that results in the ability for the basal ganglia to make a cognitive decision followed by a motor decision Considering lateral cortical interactions, another competition takes place inside the cortex allowing this latter to make a cognitive and a motor decision We show how this dual competition endows the model with two regimes One is oriented towards action-outcome and is driven by reinforcement learning, the other is oriented towards stimulus-response and is driven by Hebbian learning The final decision is made according to a combination of these two mechanisms with a gradual transfer from the former to the latter We confirmed these theoretical results on primates using a two-armed bandit task and a reversible bilateral inactivation of the internal part of the globus pallidus
Which of the following is not true about the organizational principles of prefrontal cortex?
Activation in the lateral regions of the PFC is related to information related to personal experience and emotional states.
Shallice & Burgess (1991) conducted a study with 3 patients with damage to frontal lobe regions of the brain. The task designed was known as the Saturday Morning Task. What were the results of this study?
All 3 participants were impaired on this task. They understood the instructions, but had trouble sticking to the rules of the task.
Neural Mechanisms of Attention and Perceptual Selection
Although most of the experiments discussed in this chapter focus on visual attention, this should not be taken to suggest that attention is only a visual phenomenon Finally, we will consider the neural mechanisms underlying attentional selection of simple stimulus features such as color and location, or higher-order features such as objects, when we are searching for something or someone in a complex scene, like a friend in a busy airport terminal Spatial attention influences the processing of visual inputs: Attended stimuli produce greater neural responses than do ignored stimuli, and this process takes place in multiple visual cortical areas Reflexive attention is automatic and is activated by stimuli that are conspicuous in some way Reflexive attention also results in changes in early sensory processing, although only transiently A hallmark of reflexive attention is inhibition of return, the phenomenon in which the recently reflexively attended location becomes inhibited over time such that responses to stimuli occurring there are slowed Extrastriate cortical regions specialized for the perceptual processing of color, shape, or motion can be modulated during visual attention to the individual stimulus features Selective attention can be directed at spatial locations, at object features, or at an entire object Attention increases coherence of neuronal oscillations between visual areas
ERN
An ERP component sensitive to conflict that has been localized to the anterior cingulate cortex.
Why is it that the Error Detection Hypothesis isn't fully representative of what is going on in the Anterior Cingulate Cortex?
An error is not always required to see upregulation in the ACC to reengage cognitive control-greater FRN activity occurs when feedback is given rarely as compared to frequently.
Error Detection Hypothesis is Insufficient
An error is not required to see an increase in medial frontal cortex activity -Feedback-Related Negativity = Evident when feedback is rare whether it signals an error or not Time Estimation Task: Press a button 2.5s after stimulus onset Feedback Manipulations: -Valence -Frequency Medial Frontal Electrode Site An error is not required to see an increase in medial frontal cortex activity -Feedback-Related Negativity = Evident when feedback is rare whether it signals an error or not = With Expectations -Stroop Task = Errors are rare but MFC activity is high for Incongruent Trials = With Habitual Responses -Semantic Generation Tasks = Requirement to choose between suitable alternatives results in increased MFC activity = Between Alternative Responses All sources of high conflict When conflict is high a monitoring system is required to reinstate cognitive control to meet task demands
error-related negativity
An event-related potential component in EEG that can be detected at the scalp when an error is made
Selective Attention and the Anatomy of Attention
At the end of the 19th century, the great American psychologist William James made an astute observation: -Everyone knows what attention is -It is the taking possession by the mind, in clear and vivid form, of one out of what seem several simultaneously possible objects or trains of thought -Focalization, concentration of consciousness are of its essence -It implies withdrawal from some things in order to deal effectively with others, and is a condition which has a real opposite in the confused, dazed, scatterbrain state Arousal refers to the global physiological and psychological state of the organism, and it is best thought of on a continuum ranging from deep sleep to hyper alertness In contrast, selective attention is not a global brain state This is goal-driven control, steered by an individual's current behavioral goals and shaped by learned priorities based on personal experience and evolutionary adaptations Your reaction is stimulus driven and is therefore termed stimulus-driven control, which is much less dependent on current behavioral goals Attentional control mechanisms influence specific stages of information processing, where it is said that "selection" of inputs takes place—hence the term selective attention This chapter focuses on the mechanisms of selective attention and its role in perception and awareness Selective attention is the ability to focus awareness on one stimulus, thought, or action while ignoring other, irrelevant stimuli, thoughts, and actions -Arousal is a global physiological and psychological brain state, whereas selective attention describes what we attend and ignore within any specific level of arousal Specific networks for the control of attention include cortical and subcortical structures Attention influences how we process sensory inputs, store that information in memory, process it semantically, and act on it
In the exogenous cueing task What happens when the delay is short (name for this) and when the delay is long(name for this)?
Attention Capture: time to make the button press is faster to same-side targets when the delay is short. Inhibition of Return: time to make the button press is slower to same-side targets when the delay is long.
Models of Attention
Attention can be divided into two main forms: voluntary attention and reflexive attention Voluntary attention, also known as endogenous attention, is our ability to intentionally attend to something, such as this book Reflexive attention, also referred to as exogenous attention, is a bottom-up, stimulus-driven process in which a sensory event—maybe a loud bang, the sting of a mosquito, a whiff of garlic, a flash of light, or motion—captures our attention We all know what overt attention is: When you turn your head to orient toward a stimulus—whether it is for your eyes to get a better look or your ears to pick up a whisper—you are exhibiting overt attention.his behavior is covert attention Much of attention research focuses on understanding covert attention mechanisms, because these necessarily involve changes in internal neural processing and not merely the aiming of sense organs to better pick up information Attention involves both top-down, goal-directed processes and bottom-up, stimulus-driven mechanisms, and it can be either overt or covert -According to early-selection models, a stimulus need not be completely perceptually analyzed before it can be selected for further processing or rejected as irrelevant -Broadbent proposed such a model of attention Late-selection models hypothesize that attended and ignored inputs are processed equivalently by the perceptual system, and that selection can occur only upon reaching a stage of semantic encoding and analysis Our perceptual system contains limited-capacity stages at which it can process only a certain amount of information at any given time, resulting in processing bottle-necks -Attention limits the information to only the most relevant, thereby preventing overload Spatial attention is often thought of metaphorically as a "spotlight" of attention that can move around as the person consciously desires or can be reflexively attracted by salient sensory events
Covert Attention
Attention directed to objects/places of interest absent head or eye movements
Take-Home Points
Attention operates at multiple stages of processing, even subcortically in the sensory pathways Top-Down and Bottom-Up attention appear to be associated with dissociable dorsal and ventral attention networks = sources of attention Attentional Control Networks signal sensory processors = sites of attention to be on alert Increased connectivity has been reported for control sites and sensory processing sites selective for a location, a feature, or an object Stimulus information is processed without awareness in neglect - perhaps awareness depends upon the interaction of bottom-up sensory signals and top-down control signals
What is the definition of Covert Attention?
Attention that is directed towards places/objects of interest absent head or eye movement.
covert attention
shifting attention from one place to another while keeping the eyes stationary
What technique was used here to examine brain activity differences in the time estimation task?
Medial Frontal Electrode Site
_______, a term that refers collectively to the set of processes that support goal-directed behavior, is the domain of the ________ lobe.
COGNITIVE CONTROL/ frontal
Early-Selection Models Versus Late-Selection Models
Cambridge University psychologist Donald Broadbent elaborated on the idea that the information-processing system has processing bottlenecks Early selection is the idea that a stimulus can be selected for further processing or be tossed out as irrelevant before perceptual analysis of the stimulus is complete In contrast, models of late selection hypothesize that the perceptual system first processes all inputs equally, and then selection takes place at higher stages of information processing that determine whether the stimuli gain access to awareness, are encoded in memory, or initiate a response Cherry observed in his cocktail party experiments that salient information from the unatt ended ear was sometimes consciously perceived—for example, when the listener's own name or something very interesting was included in a nearby conversation To test these competing models of attention, researchers employed increasingly sensitive methods for quantifying the effects of attention, as described next
Feature-Based Attention
Can attention be allocated to visual features of objects? -3 Cueing Conditions: 1. Neutral: Not Diagnostic 2. Spatial Attention: Cued Target Location with 100% validity 3. Feature Attention: Cued Direction of Movement with 100% validity Task: Speed increase in one of the four dot fields? -YES Results: -Spatial Attention -More accurate target detection for cued than neutral trials with an SOA of 300ms -Feature Attention -More accurate target detection for cued than neutral trials with an SOA of 500 ms
Brief Review
Characteristics of Attention -limited capacity -selective Deployment of Attention -overt versus covert attention -voluntary versus reflexive attention Attention improves processing speed and makes it more accurate Sites of Attention in the Brain Does attention modulate part of a sensory system and affect everything downstream? -Or, does it operate on specific processors that correspond to what is attended? Sites of Attention in the Brain -attention to spatial locations = LGN, early visual cortex, P1 component -attention to features = motion - V5/MT, color - V4 -attention to objects = faces - PPA, houses - FFA Modulatory effects of attention are evident in specialized cortical sites
Early and Late Selection Models
Clearly, some information has been selected, but at what stage of processing does selection take place? Where is the gate? -SENSORY INPUTS -GATING MECHANISM -BEHAVIORAL OUTPUT Perceptual analysis does not have to be complete before a stimulus can be selected for further processing or rejected as irrelevant Attended/Ignored inputs processed equivalently by perceptual system, reach stage of semantic analysis; then selection occurs Today: signal is attenuated but if salient enough will pass through the gate
Processes that Contribute to Cognitive Control
Cognitive Control collection of processes that permit the execution of goal-oriented behavior Requires: -active representations of behaviorally-relevant goals -focus on relevant information / ignore irrelevant information -ability to flexibly transition from one plan to another depending on current task constraints -monitoring systems that signals failure and alerts us to other potential sources of conflict What is the Mechanism for Goal-Selection?
What is Cognitive Control?
Cognitive Control collection of processes that permit the execution of goal-oriented behavior Requires: -active representations of behaviorally-relevant goals -focus on relevant information / ignore irrelevant information•ability to flexibly transition from one plan to another depending on current task constraints -monitoring systems that signals failure and alerts us to other potential sources of conflict
The Anatomy Behind Cognitive Control
Cognitive control, sometimes referred to as executive function, refers to the set of psychological processes that enable us to use our perceptions, knowledge, and goals to bias the selection of action and thoughts from a multitude of possibilities Collectively, the behaviors thus enabled can be described as goal-oriented behavior, frequently requiring the coordination of a complex set of actions that may unfold over an extended period of time.As we learned in Chapter 8, the most posterior part of the frontal lobe is the primary motor cortex Anterior and ventral to the motor cortex are the secondary motor areas , made up of the lateral premotor cortex and the supplementary motor area The remainder of the frontal lobe is termed the prefrontal cortex We will refer to four regions of prefrontal cortex in this chapter: the lateral prefrontal cortex, the frontal pole, the orbitofrontal cortex, and the medial frontal cortex The prefrontal cortex has many projections to the contralateral hemisphere—projections to homologous prefrontal areas via the corpus callosum, as well as bilateral projections to premotor and subcortical regions Cognitive control is the collection of mental abilities that involve planning, controlling, and regulating the flow of information processing Cognitive control gives us the flexibility required for goal-oriented behavior The prefrontal cortex includes four major components: lateral prefrontal cortex, frontal pole, orbitofrontal cortex, and medial frontal cortex These parts of the brain have become very prominent in mammals, and especially in primates
What is the main idea of the cocktail party effect?
Competing auditory input does not prevent us from successfully attending to a conversation.
Utilization Behavior
Condition characterized by actions that are completely stimulus driven following frontal lobe damage - situational context is no longer keeps behavior in check.
Balint's Syndrome
Condition characterized by attention to a very small subset of available information that is mislocalized in space.
Which visual search task utilizes a target defined by a unique combination of features?
Conjunction Search
You are looking for a red book with yellow typeface in a stack of books that are blue with yellow typeface and red with white typeface. To find the book, you use a ________ search. In this case, the amount of time required to find the book will _______ if some of the books are removed from the pile.
Conjunction/ decrease
Ocular Apraxia
Disorder characterized by impaired visual field scanning and a disruption of voluntary eye movements.
Improving Cognitive Control Through Brain Training
Do older people fret when they catch you playing an action video game instead of reading your history assignment? A growing body of evidence suggests that playing action video games may improve some aspects of cognitive function—in particular, tasks involving cognitive control and attention such as visual search, n-back tasks, and response inhibition Only those who did the active video game training showed an improvement on the generalization test, and there, too, the improvements were evident only on switch trials
Can Brain Training Improve Cognitive Control?
Does it work? -depends on who you ask -big-picture question is to do with far transfer; are benefits seen on tasks that are not themselves trained NeuroRacer Dual Tasking: keep your vehicle on the road and make a button press when you see a sign with a green circle Dual Tasking Performance Training-Based Gains in Performance & MFC Activity Improvements also evident in pre- and post-training cognitive assessments Auditory = Pitch Discrimination Visual = Size Judgement = Performed separately or together with repeated rules from one trial to the next or a rule switch, which required more cognitive control Improvements evident after action video-game training, but
Synchronous Neuronal Firing
Drifting Gratings: Attend one, detect to slight shape change Coherence - synchrony of electrical signals in V1a or V1b and V4
Mechanisms of Goal-Based Selection
Dynamic filtering could influence the contents of information processing in at least two distinct ways Evidence for a loss of inhibitory control with frontal lobe dysfunction comes from electrophysiological studies The more curious aspect is shown in the bottom panel of Figure 12.26a: Patients with frontal lobe lesions have enhanced evoked responses This difference was absent in patients with prefrontal lesions, especially for stimuli presented to the ear contralateral to the lesion Second, given that aging is thought to disproportionately affect prefrontal function, perhaps inhibitory goal-based control is more dependent on pre-frontal cortex than are the attentional mechanisms that underlie the amplification of task-relevant information Patients with prefrontal cortex damage lose inhibitory control -For example, they cannot inhibit task-irrelevant information A network spanning prefrontal cortex and posterior cortex provides the neural substrates for inter-actions between goal representations and perceptual information The inhibition of action constitutes another form of cognitive control -The right inferior frontal gyrus and the subthalamic nucleus are important for this form of control Goal-oriented behavior involves the amplification of task-relevant information and the inhibition of task-irrelevant information -Amplification and inhibition may entail separate processes, given that aging selectively affects the ability to inhibit task-irrelevant information -Active video game playing has been hypothesized to improve some aspects of cognitive function, such as task switching, perhaps because the games require coordinating multiple subgoals
In the ________ task, an arrow cue is most often a(n) _______ predictor of upcoming target location. Under these circumstances, target detection time is _______ than it is in the baseline (i.e., bidirectional arrow) control condition.
ENDOGENOUS CUEING/ VALID/ FASTER
What were the results of the time estimation task and why might they be considered surprising?
Feedback-Related Negativity = Evident when feedback is rare whether it signals an error or not
cognitive control
Effective control of thinking in a number of areas, including controlling attention, reducing interfering thoughts, and being cognitively flexible
Object-Based Attention Is attention affected by the bounds of an object?
Egly, Driver & Rafal VALID INVALID: 75% SAME OBJECT INVALID: DIFFERENT OBJECT 25% 75% OF THE TRIALS Are there additional object-based costs associated with target detection in spatial cueing tasks? -YES More time is required to shift attention to targets in uncued locations on a different object = object-based component to spatial cueing
stimulus-response decisions
Encoding and dealing with conflicting information is essential for successful decision making in a complex environment In the present fMRI study, stimulus conflict and response conflict are contrasted in the context of a perceptual decision-making dot-motion discrimination task Stimulus conflict was manipulated by varying dot-motion coherence along task-relevant and task-irrelevant dimensions Response conflict was manipulated by varying whether or not competing stimulus dimensions provided evidence for the same or different responses The right inferior frontal gyrus was involved specifically in the resolution of stimulus conflict, whereas the dorsal anterior cingulate cortex was shown to be sensitive to response conflict Additionally, two regions that have been linked to perceptual decision making with dot-motion stimuli in monkey physiology studies were differentially engaged by stimulus conflict and response conflict The middle temporal area, previously linked to processing of motion, was strongly affected by the presence of stimulus conflict On the other hand, the superior parietal lobe, previously associated with accumulation of evidence for a response, was affected by the presence of response conflict These results shed light on the neural mechanisms that support decision making in the presence of conflict, a cognitive operation fundamental to both basic survival and high-level cognition
What is the functional significance of the Error Detection Hypothesis?
Error detection results in increased cognitive control. Alert lateral PFC to reactivate goal in WM.
primary reinforcers
Events that are inherently reinforcing because they satisfy biological needs
Which of the following is NOT true of the lateral PFC?
Evidence from single neuron recordings in monkeys indicate cells in the lateral PFC respond to either preferred objects or preferred locations but not both.
What is cognitive control sometimes referred to as?
Executive Function
In contrast to the patient with neglect, a Bálint's patient demonstrates the following main deficits that are characteristic of the disorder EXCEPT
Extinction
Eye Movements
Eye movements are biased in a rightward direction during performance of a visual search task and at rest R. Sided Lesion Control R. Sided Lesion w/ Neglect
True/False The frontal pole, which is the anterior-most part of the prefrontal cortex, is most likely to be active in tasks characterized by low levels of complexity, like making a left-sided button press whenever a flower is presented.
FALSE - HIGH LEVELS OF COMPLEXITY
True/False Work conducted using the exogenous cueing task has indicated that the sudden appearance of a light flash slows detection of a target presented in the same location if the amount of time between the light and the target is short (i.e., less than 200ms) because the light is distracting.
FALSE - INHIBITION OF RETURN IS EVIDENT WHEN THE CUE-TO-TARGET DELAY IS LONGER THAN 300 MS
True/False Recordings from PFC neurons have shown that these cells increase their firing rate in the presence of a cue but that activity falls to baseline levels shortly after the onset of a delay.
FALSE - PFC CELLS FIRE CONTINOUSLY THROUGHOUT THE DELAY PERIOD
True/False Together with the frontal pole, premotor cortex and the supplementary motor area have been identified a critical structures for cognitive control.
FALSE - PREMOTOR CORTEX AND THE SUPPLEMENTARY MOTOR ARE PART OF MOTOR CORTEX
True/False . Relative to healthy controls, Knight & Grabowecky (1995) reported that patients with temporoparietal lesions showed enhanced evoked responses to auditory tones, while patients with frontal lobe lesions showed reduced evoked responses to these tones.
FALSE - THE REVERSE IS TRUE ... TEMPOROPARIETAL LESIONS (AUDITIORY CORTEX) = REDUCED RESPONSE; FRONTAL LOBE = ENHANCED RESPONSE
True/False When we voluntarily deploy attention to a specific spatial location, we can detect a change in that location more efficiently; this benefit does not extend to feature-selective attention.
FALSE - THERE IS EVIDENCE FOR MORE EFFICIENT FEATURE PROCESSING WITH FOCUSED ATTENTION BUT MORE TIME IS REQUIRED BETWEEN CUE AND TEST/PROBE DISPLAYS FOR THESE BENEFITS TO BE SEEN
True/False Individuals with frontal lobe damage are generally better planners that healthy controls. In the Sunday Morning Errand task, for example, frontal lobe patients followed instructions without errors. Despite superior goal planning, the same patients are impaired on standardized neuropsychological tests.
FALSE - THESE PATIENTS SHOW DEFICITS IN GOAL-ORIENTED BEHAVIOR, LIKE PLANNING, BUT PERFORM NORMALLY ON STANDARDIZED NEUROPSYCHOLIGICAL TESTS.
True/False Research suggests that attentional modulation of LGN neurons that communicate with V1 is mediated by excitatory cells in the thalamic reticular nucleus (i.e. TRN cells).
FALSE - TRN cells are inhibitory
Dorsal Attention Network inferior frontal junction
FEF stimulation appears to drive selective attention to spatial locations = What about features? -Is there a brain region that drives feature selection? -Yes -Inferior Frontal Junction
Dorsal Attention Network frontal eye fields
FEF stimulation results in movement of the eyes to a specific spatial location = Do FEF neurons control voluntary attention to spatial locations as well? -Yes, it seems so Low-level stimulation improved task performance for a preferred target in the receptive field Specific to targets in location that an eye movement would otherwise have been directed to FEF stimulation results in movement of the eyes to a specific spatial location = Does FEF stimulation change the firing rate in visual cortex? -Yes again
When faces are attended, which site of attention is engaged?
FFA
Decision Making
Go back to the hot summer day when you thought, "Hmm . . . that frosty, cold drink is worth looking for. I'm going to get one." Normative decision theories define how people ought to make decisions that yield the optimal choice Descriptive decision theories attempt to describe what people actually do, not what they should do A some-what similar way of classifying decisions is to divide them into action-outcome decisions or stimulus-response decisions Model-based means that the agent has an internal representation of some aspect of the world and uses this model to evaluate different actions Model-free means that you have only an input-output mapping, similar to stimulus-response decisions Decisions that involve other people are known as social decisions Dealing with other individuals tends to make things much more complicated—a topic we will return to in Chapters 13 and 14 A decision involves the selection of one option among several -It typically involves an evaluation of the expected outcome associated with each option -The subjective value of an item is made up of multiple variables that include payoff amount, context, probability, effort/cost, temporal discounting, novelty, and preference Single-cell recordings in monkeys and fMRI studies in humans have implicated frontal regions, including the orbitofrontal cortex, in value representation Reward prediction error is the difference between the expected reward and what is actually obtained -The RPE is used as a learning signal to update value information as expectancies and the valence of rewards change -The activity of some DA neurons provides a neuronal code of prediction errors DA neurons also appear to code other variables that may be important for goal-oriented behavior and decision making, such as signaling the salience of information in the environment
Retrieval and Selection of Task-Relevant Information
Goal-oriented behavior requires selecting task-relevant information and filtering out task-irrelevant information Here, selection refers to the ability to focus attention on perceptual features or information in memory To capture this idea, the PFC has been conceptualized as a dynamic filtering mechanism For example, for the noun rope, multiple answers are reasonable, including tie, lasso, and twirl.In an environment where multiple sources of information compete for attention, however, these patients are in a particularly vulnerable condition: They have difficulty maintaining their focus on a goal
An action that is no longer under the control of reward, but is stimulus driven and considered automatic.
Habit
Unilateral Spatial Neglect
Halligan & Marshall, 1998 -It doesn't seem right to me that the word neglect should be used to describe it -I think concentrating is a better word -If I'm walking anywhere and there's something in my way, if I'm concentrating on what I'm doing, I will see it and avoid it -The slightest distraction and I won't see it Rightward attentional bias following right-sided brain damage Patients may only eat from the right side of their plate, shave the right side of their face, read from the right page of a book May have limited awareness of the deficit Not a visual field cut = Profile depends upon the location and extent of damage
Early (and Accidental) Studies of Attention
Hermann von Helmholtz Goal: Investigate visual processing of briefly perceived stimuli Letters painted on a large screen Brief light flash exposed screen in dark room Unexpected Result: -Eye movements required to examine letters -With eyes fixed at center, could successfully attend to any screen location -Letters at Focus of Attention better perceived than those outside focus = COVERT ATTENTION
Patients with left inferior frontal gyrus damage show difficulty on verbal generation tasks that require _______
High Filtering
What new insights were gained from the fMRI study conducted with healthy individuals during the PFC-Supported Filtering Operations task?
High Filtering > Low Filtering: Activity in the Inferior Frontal Gyrus sensitive to selection demands. Verb Generation > Baseline: Activity in the Temporal Lobe sensitive to semantic retrieval.
Disruption of PFC-Mediated Control
How is PFC-mediated control affected when participants are challenged by dual tasking? 1. PFC is critical for working memory 2. Evidence suggests that PFC inhibits and/or facilitates processing of task-relevant info 3. If PFC is occupied with a difficult working memory task does FFA activity increase? How is PFC-mediated control affected when participants are challenged by dual tasking? -YES When resources are tied up, interfering information is more difficult to ignore -PFC Activity: Hard WM Test > Easy WM Test -FFA Activity: Hard WM Test > Easy WM Test
In a neuroimaging experiment conducted by D'Esposito and colleagues participants were either told to attend to faces and ignore scenes or vice-versa. Relative to a baseline control condition activity in FFA ________ when faces were task-relevant and ________ when scenes were task-relevant. When healthy older adults were tested with this task, the ________ effect was missing.
INCREASED/ DECREASED/ suppression
Neglect not limited to perceptual experience
Imagine that you are at the Cathedral -What is Visible in the Piazza? View from Cathedral View toward Cathedral Neglect biases attention to the right side of a spatial representation retrieved from memory, but is not a memory deficit
The Cocktail Party Effect
Imagine yourself at a Super Bowl party having a conversation with a friend His curiosity and subsequent research helped to found the modern era of attention studies with what was dubbed the cocktail party effect Attention—in this case voluntary attention—affected what was processed As foreshadowed by William James, bottlenecks in information processing—stages through which only a limited amount of information can pass—seem to occur at stages of perceptual analysis that have a limited capacity This question has led to one of the most debated issues in psychology over the past six decades: Are the effects of selective attention evident early in sensory processing or only later, after sensory and perceptual processing are complete? Perhaps it is not either-or; it may be that attention affects processing at many steps along the way from sensory transduction to awareness
Hermann von Helmholtz and Covert Attention
In 1894, Hermann von Helmholtz was investigating aspects of the visual processing of briefly perceived stimuli As noted earlier, covert means that the location toward which he directed his attention could be different from the location toward which he was looking As Helmholtz wrote in his Treatise on Physiological Optics, These experiments demonstrated, so it seems to me, that by a voluntary kind of intention, even without eye movements, and without changes of accommodation, one can concentrate attention on the sensation from a particular part of our peripheral nervous system and at the same time exclude attention from all other parts Models of how the brain's attention system might work were built from these data and from observations like those of Helmholtz—as well as from everyday experiences, such as attending a crowded party
Describe one experiment that indicates activity in specialized visual processing sites is modified by attention. Include in your response a description of the method (1 point) and the result/conclusion
In Posner's voluntary cueing task researchers are trying to figure out if there are stronger ERP waveforms invalid tasks as opposed to invalid tasks During this task, participants had to look at a screen and make a button press depending on what side the target appeared on the screen Before each trial, the participants were given an arrow cue to point them to which direction they should shift their attention to, the right side or the left side Sometimes the target would appear on the directed side, known as a valid trial and sometimes it would appear on the opposite side of the cued direction, known as an invalid trial For example, a participant sees an arrow cue directing them to look right when the target then actually appears on the left, in which the participant would want to press the button indicating the target was on the left Results showed that when the target appeared in the cued location, the amplitude of the P1 ERP waveform was indeed enhanced Meaning that when attention is already at a cued location the brain is primed and ready for the target to appear and to make your response quicker with more ease
What is the difference between endogenous and exogenous cuing?
In endogenous cuing, orienting attention to the cue is voluntary and driven by the participant's goals, whereas exogenous cuing automatically captures attention.
Visual Search
In everyday perception, voluntary attention and reflexive attention interact in a push-pull fashion, struggling to control the focus of our attention How are voluntary and reflexive spatial attention mechanisms related to visual search? This phenomenon is called pop-out because the red O literally appears to pop out of the array of green letters on the basis of its color alone If the target shares features with the distractors, how-ever, so that it cannot be distinguished by a single feature, then the time it takes to determine whether the target is present or absent in the array increases with the number of distractors in the array This type of search is known as a conjunction search because the target is defined by the conjunction of two or more features This concept is called the feature integration theory of attention, and understanding the neural bases of these mechanisms remains of central importance in cognitive neuroscience This study showed that conjunction search affects the P1 wave in much the same way that cued spatial attention does, supporting the idea that a kind of spotlight of spatial attention is employed during visual search, and revealing the neural basis of that effect: modulations of early cortical visual processing
What was the main piece of contrary evidence to the early selection model of processing?
In experiments conducted by Cherry and colleagues, information from the unattended ear were sometimes consciously perceived.
pulvinar
In humans, the posterior portion of the thalamus It is heavily involved in visual processing and direction of attention
Which of the following is a result of frontal lobe lesions?
Inability to plan and make decisions.
Test of Reflexive Attention exogenous cueing
Jonides What do you suspect happens? -Attention Capture: time to make the button press is faster to same-side targets when the delay is short Inhibition of Return: time to make the button press is slower to same-side targets when the delay is long Instruction: Make a Button Press as Quickly as Possible when the Target Appears
The Dorsal Attention Network
Joseph Hopfinger and his colleagues and Maurizio Corbetta and his coworkers both employed event-related fMRI to study attentional control Later we will discuss the work of Corbetta and colleagues to complete the story FINDING THE SOURCES OF ATTENTIONAL CONTROL OVER SPATIAL ATTENTION -Recall that Hopfinger and his coworkers used a modified spatial cuing paradigm like the one shown in Figure 7.15 -These regions together are now called the dorsal attention network -We now understand that this dorsal frontoparietal network reflects the sources of attentional signals in the goal-directed control of attention -Third, when participants only passively viewed the presented cues—and didn't attend to them or act on them—then the frontoparietal brain regions that were active in the former condition were not activated during passive viewing, even though the visual cortex was engaged in processing the visual features of the passively viewed cues -How does this network function to modulate sensory processing? LINKING THE CONTROL NETWORK FOR SPATIAL ATTENTION TO ATTENTIONAL CHANGES -First let's look at the evidence that activity in the dorsal attention network is actually linked to attention-related changes in sensory processing -In Hopfinger's study, after the cue was presented but before the target displays appeared, activations were observed not only in the dorsal attention network, but also in visual cortical regions that would later process the incoming target -Do any data support this biasing effect on the visual cortex? FRONTAL CORTEX AND ATTENTIONAL CONTROL -Indirect evidence comes from patients with prefrontal cortical lesions -Neurologist Robert T. Knight and his colleagues found that patients with frontal cortex damage due to stroke had "decreased" visually evoked responses in ERP recordings over visual cortex -The researchers note that these two studies demonstrate striking parallels in neural mechanisms: In both, the PFC seems to be the source of top-down biasing signals, with the FEF providing signals for spatial attention and the IFJ providing signals for object or feature attention THE PARIETAL CORTEX AND CONTROL OF ATTENTION -The areas along the intraparietal sulcus and the superior parietal lobule in the posterior parietal lobe are the other major cortical regions that belong to the dorsal attention network -Let's now turn our attention to the ventral network
Goal-Based Selection Mechanisms
Knight et al. -Passive Listening Task -Measure: Evoked Responses to Tones Normal Evoked Responses=Abnormal Evoked Responses -Attenuated A1 Response -Site of Damage -Enhanced A1 Response What going on here? -Loss of Inhibitory Control -Standard Difference in N1 Amplitude to Tones with and without Attention = Failed Inhibition of To-Be-Ignored Tones -Enhancement and Suppression Effects Gazzaley et al. -Prioritize/RememberControl Condition -How is activity in domain-specific cortex modulated by task demands? -Older adults = selective inhibition problem / Does not indicate source of top-down modulation BUT long-range connections between PFC and cortical processors have been identified
Wisconsin Card Sorting adapted for the fMRI scanner
Konishi et al. -Wisconsin Card Sorting adapted for the fMRI scanner 3 Experimental Conditions: 1D Perceptual Baseline; No Shift Requirements -The rule was explicitly stated and participants applied this rule throughout the scanning run 2D Known Shift -Again, the rules were explicitly stated, and participant knew to apply the new rule upon receiving an error message 3D Random Shift Between all 3 Rules -Participants learned new rule by trial/error; switch after 10 successful trials
Thompson-Schill et al. (1997) reported that individuals with _______ damage find it difficult to filter out competitors in a verb generation task; results from the same study indicate that _______ is intact.
LEFT INFERIOR FRONTAL GYRUS/ SEMANTIC KNOWLEDGE
In tests utilizing scrambled and intact faces exploring working memory, results suggest that
LPFC activity is modulated as a function of WM load
Comparing Neglect and Bálint's Syndrome
Let's compare the pattern of deficits in neglect with those of the patient with Bálint's syndrome described at the beginning of the chapter Simultanagnosia is a difficulty in perceiving the visual field as a whole scene, such as when the patient saw only the comb or the spoon, but not both at the same time Ocular apraxia is a deficit in making eye movements to scan the visual field, resulting in the inability to guide eye movements voluntarily: When the physician overlapped the spoon and comb in space as in Figure 7.1c, the Bálint's patient should have been able, given his direction of gaze, to see both objects, but he could not -Optic ataxia is a problem in making visually guided hand movements: If the doctor had asked the Bálint's patient to reach out and grasp the comb, the patient would have had a difficult time moving his hand through space toward the object -To answer these questions, let's look next at the cognitive and neural mechanisms of attention
Unilateral Spatial Neglect neuropsychological tests
Line Cancellation Copying
Which of the following statements describes a conjunction search?
Looking for a yellow daisy in a field of yellow tulips and red daisies. Finding my friend, who has blond hair and is wearing a red dress among other girls with blond hair in black dresses and black hair in red dresses.
Receptive Field Size and the size of the stimulus
MEG Data If the receptive field is small and the stimulus is large, then no competition and no effect of attention; if the stimulus is smaller, then attention should exert an effect
Attention to Visual Features
MEG Investigation Perceptual information is the same, but activity increases in color-selective sites when color is attended and in motion-selective sites when movement is attended Both rectangles appear in the receptive field for this cell - the firing rate is modified by whether the preferred stimulus is attended or not
Which of the following is not true about the neuronal mechanisms of attention and perceptual selection?
MEG activity in V4 is increased when movement is attended, while the activity in V5 is increased when color is attended.
Recovery from Neglect
Many patients recover from the acute symptoms of neglect But may experience residual impairments, especially when two objects compete for attention
Dynamic Filtering
Mechanism that permits us to focus on goal-relevant information and filter out competing content..
Cocaine addicts show hypoactivation of the _______ and problems with response inhibition on no-go trials.
Medial Frontal Cortex
Which of the following is NOT a primary reinforcer
Money
Medial Frontal (ACC)as the Task Master
Monitoring is required for execution of 1. Well-learned behaviors 2. Novel behaviors and behaviors performed in an unusual context Anterior Cingulate Activation foci from 38 fMRI studies with high monitoring demands
The Neuropsychology of Attention
Much of what neuroscientists know about brain attention systems has been gathered from examinations of patients who have brain damage that influences attentional behavior Let's consider how brain damage has helped us understand these mechanisms Unilateral spatial neglect may result from damage to the right parietal, temporal, or frontal cortices, as well as to subcortical structures This kind of damage leads to reduced attention to and processing of the left-hand side of scenes and objects, not only in external personal hemi space but also in internal memory Neglect is not the result of sensory deficits, because visual field testing shows that these patients have intact vision -Under the right circumstances, they can easily see objects that are sometimes neglected A prominent feature of neglect is extinction, the failure to perceive or act on stimuli contralateral to the lesion when presented simultaneously with a stimulus ipsilateral to the lesion Patients with Bálint's syndrome have three main deficits characteristic of the disorder: difficulty perceiving the visual field as a whole scene, an inability to guide eye movements voluntarily, and difficulty reaching to grab an object
Results from a training study conducted with the game NeuroRacer indicated that older adults assigned to a _______ training group show improvements on standardized tests of working memory and attention.
Multitask
medial frontal cortex
Neurons in male rats have larger dendritic fields
Object Attention
Now that we've described the effects of spatial-based attention and feature-based attention in visual cortex, let's turn to another question: Can attention also act on higher-order stimulus representations—namely, objects? For lack of a better word, we can refer to these qualities as object properties—elementary stimulus features that, when combined in a particular way, yield an identifiable object or person Behavioral work has demonstrated evidence for object-based attention mechanisms Holding spatial distance constant, he discovered that two perceptual judgments concerning the same object could be made simultaneously without loss of accuracy, whereas the same two judgments about different objects could not For example, when the wrenches were oriented horizontally and the upper-left-quadrant location was cued, the upper-right-quadrant location would be spatially uncued but be within the same object When the wrenches were vertically oriented, however, that location would be spatially uncued and within a different object What's more, they found that in visual cortical areas V1 through V4, increased activity occurred in uncued locations that were located on the same object as the cued location, compared to when the uncued location was not on the cued object Importantly, these findings show that even when spatial attention is not involved, object representations can be the level of perceptual analysis affected by goal-directed attentional control SPIKES, SYNCHRONY, AND ATTENTION -We now know that when attention is focused on a stimulus, neurons in the visual system that code that stimulus increase their postsynaptic responses and their firing rates Bosman and colleagues believe that such communication occurs when the attended signals passing from V1 to V4 induce the gamma neuronal synchronization with V4
PFC - Organizational Principles
Object = Button Press Posterior to Anterior Hierarchical Gradient Dorsal - Manipulation / "How"Posterior - Less Abstract / Complex Medial - Internal / Memory & Emotion PFC - Organizational Principles Anterior - More Abstract / Complex Lateral - External / Perceptual Ventral - Maintenance / "What"Cognitive Control Network Consistent with PFC anatomy, there is more between-network connectivity for the WM Task
Quantifying the Role of Attention in Perception
One way of measuring the effect of attention on information processing is to examine how participants respond to target stimuli under differing conditions of attention In these so-called cuing tasks , the focus of attention is manipulated by the information in the cue This form of cuing is known as endogenous cuing, where the orienting of attention to the cue is voluntary and driven by the participant's goals and the meaning of the cue In contrast, an exogenous cue automatically captures attention because of its physical features When a cue correctly predicts the location of the subsequent target, it is a valid trial Sometimes, though, because the target may be presented at a location not indicated by the cue, the participant is misled in an invalid trial Finally, the researcher may include some cues that give no information about the most likely location of the impending target—a neutral trial This faster response demonstrates the benefits of attention The spotlight is a metaphor to describe how the brain may attend to a spatial location This enhancement of attended stimuli, a type of early selection, is consistent with the proposal that changes in perceptual processing can happen when the participant is covertly attending a stimulus location Now, you might be thinking, "Wait a minute—responding more quickly to a target appearing at an attended location does not imply that the target was more efficiently processed in the sensory pathways." In the next section we will look closely at the effects of attention on visual processing
Voluntary Attention
Our ability to intentionally attend to something; we choose Also known as top-down or goal-directed attention
Goal-Oriented Behavior
Our actions are not aimless, nor are they entirely automatic—dictated by events and stimuli immediately at hand Goal-oriented actions are based on the assessment of an expected reward or value and the knowledge that there is a causal link between the action and the reward A habit is defined as an action that is no longer under the control of a reward, but is stimulus driven; as such, we can consider it automatic Goal-oriented actions require processes that enable us to maintain our goal, focus on the information that is relevant to achieving that goal, ignore or inhibit irrelevant information, monitor our progress toward the goal, and shift flexibly from one sub-goal to another in a coordinated way Working memory can be conceptualized as the information formed by the combination of a task goal and the perceptual and long-term knowledge relevant for achieving that goal -This form of dynamic memory emerges from the interactions of prefrontal cortex and the rest of the brain Neurons in the PFC of monkeys show sustained activity throughout the delay period in delayed-response tasks -These cells provide a neural correlate for keeping a representation active after the triggering stimulus is no longer visible Various frameworks have been proposed to uncover functional specialization within the prefrontal cortex -Three gradients have been described to account for PFC processing differences: ventral-dorsal, anterior-posterior, and lateral-medial
Subcortical Components of Attentional Control Networks
Our discussion of attentional control of cortical mechanisms has been motivated to a great extent by evidence from patients with brain damage, such as those with neglect What subcortical structures play significant roles in attentional control and selection in sensory cortex, and how do they contribute to our attentional abilities? SUPERIOR COLLICULUS -The superior colliculus is a midbrain structure made up of many layers of neurons, receiving direct inputs from the retina and other sensory systems, as well as from the basal ganglia and the cerebral cortex -In the early 1970s, Robert Wurtz and his colleagues discovered visually responsive neurons in the superior colliculus that were activated depending on how monkeys responded to stimuli -Patients with degeneration of the superior colliculus suffer from a disease known as progressive supranuclear palsy -When tested in cued attention paradigms, these patients have difficulty shifting their attention in response to a cue, and are slowed in responding to cued targets -Taken together, the animal and human findings clearly identify the superior colliculus as a participant in the brain's attentional control mechanisms PULVINAR OF THE THALAMUS -One of the many outputs from the superior colliculus goes to the inferior pulvinar -Located in a posterior region of the thalamus, the pulvinar is composed of several cytoarchitectonically distinct subnuclei, each of which has specific inputs and outputs to cortical areas of all the lobes -To figure out whether and how the pulvinar functions in attentional control, Steve Petersen, David Lee -Robinson, and their colleagues investigated cells in the dorsomedial pulvinar, which has connections with the parietal cortex -They administered microinjections of the GABA agonist muscimol, a drug that temporarily inhibits neuronal activity, to the pulvinar of monkeys to investigate how pulvinar inactivation would affect the animals' attentional ability -Petersen and colleagues also showed that when a different drug, the GABA antagonist bicuculline, was administered, the monkeys readily directed their attention covertly to contralesional targets -However, the precise mechanisms of the inter-actions between top-down cortical control over attention and the pulvinar remain incompletely understood
The Cocktail Party Effect
Overt Attention Covert Attention Competing auditory input does not keep us from successfully attending to a conversation
PFC in Top-Down Control
PFC Activity = Positive Correlation between L. PPA and L. Lateral PFC Remember Scenes = Passive View = Ignore Scenes Indirect evidence for top-down modulation of PPA by PFC
What cognitive process was investigated in the PFC-Supported Filtering Operations?
PFC-Supported Filtering
Biased Competition Model of Attention
Passive Viewing -When several items are presented at the same time, rather than sequentially, BOLD signal in V4 is reduced Selective Attention -However, if attention is directed selectively to one object, the BOLD signal reduction disappears Attention Resolves the Competition Why are these effect limited to V4?
What were the results from patient work in the PFC-Supported Filtering Operations task? What was spared, what was impaired? What part of the brain was important for normal performance?
Patients with L. Inferior Frontal damage made more errors (i.e. failed to produce a verb), but only when selection demands were high. Failure to filter out irrelevant/suboptimal responses (semantic knowledge OK)
Which is not true about the Wisconsin card sorting task?
Patients with frontal lobe lesions can successfully keep track of previous responses to inform current decisions.
Summary of Cognitive Control
Prefrontal cortex plays a critical role in goal-oriented behavior This Requires 1. Online representation of retrieved and/or perceived content 2. Top-down control to filter relevant/irrelevant inputs 3. Ability to flexibly transition from one task to another if goals change 4. A monitoring system that can alert us to potential conflictsLateral PFC -Working Memory System -Active Retention of Goal-Relevant Information Medial PFC -Works cooperatively with Lateral PFC -Monitors Activity & Upregulates Cognitive Control to Meet Task Demands
Cognitive Control Deficits
People with frontal lobe lesions—like W.R., the wayward lawyer—present a paradox Such patients may persist in a response even after being told that it is incorrect; this behavior is known as perseveration Indeed, the behavior of these monkeys has become stimulus driven Lhermitte coined the term utilization behavior to characterize this extreme dependency on prototypical responses for guiding behavior Thus, even when the drug users were not under the influence of cocaine and were not making choices related to their addiction, changes in cognitive control persisted Patients with frontal lobe lesions have difficulty executing a plan and may exhibit stimulus-driven behavior Deficits in cognitive control are found in numerous psychiatric disorders, as well as when mental health is compromised by situational factors such as stress or loneliness
Does the MEG Investigation: Color & Motion examine sites of visual attention or the source of visual attention?
Perceptual information is the same, but activity increases in color-selective sites (V4) when color is attended and in motion-selective sites (V5/MT) when movement is attended.
In a test of voluntary attention, or "endogenous cueing," where an arrow would appear right, left or bidirectional, then a stimulus would appear to the right or to the left of the valid or invalid cueing. What can be concluded from this study?
Perceptual representations of cued locations are enhanced via "the attentional spotlight".
arousal
Physiological/psychological tension
You are performing a visual search task experiment in which the participant must pick out a red O surrounded by noise elements of green X's. This is an example of what type of search?
Pop-Out Search
Visual Search Tasks
Pop-Out Search -single distinctive feature distinguishes the target from distractors -search time unaffected by number of distractors Conjunction Search -target is defined by a unique combination of features; features themselves are shared with other items/foils -search time increases with more distractors -Feature-Integration Theory
Test of Voluntary Attention endogenous cueing
Posner Instruction: Make a Button Press as Quickly as Possible when the Target Appears Does focused attention elicit faster responses to the target? -Attention can be directed voluntarily to locations or objects in the sensory environment Interpretation: Perceptual representations of cued locations are enhanced
A Puzzling Result: Does More Caution Improve Performance?
Post-Error Slowing = following an error, response times slow down but the slowdown is rarely associated with more accurate responses What is going on? 1. Stricter Decision Threshold 2. Reduced Perceptual Sensitivity
Which area of the PFC is responsible for tasks that require LESS abstraction?
Posterior
how did the time estimation task work and what was the objective of the study?
Press a button 2.5s after stimulus onset An error is not required to see an increase in medial frontal cortex (anterior cingulate) activity.
The Ventral Attention Network
So far, we have learned that the dorsal attention net-work is involved in focusing attention on items related to our current behavioral goals According to Corbetta and his colleagues, this reaction to salient, unexpected, or novel stimuli is supported by the ventral attention network Together, the dorsal and ventral attention networks cooperate to make sure attention is focused on behaviorally relevant information, with the dorsal attention network focusing attention on relevant locations and potential targets, and the ventral attention network signaling the presence of salient, unexpected, or novel stimuli, enabling us to reorient the focus of our attention
Frontal Lobe Lesions perseveration
Sorting Rules: -Color -Number -Shape 1. Explicit Instructions NOT Provided = Working Memory for Features Relevant on a Previous Trial 2. Rule Change after 10 Successful Trials = Flexibility / Task Switching Patients with frontal lobe lesions cannot keep track of previous responses to inform current decision & perseverate when rules change
Frontal Lobe Lesions perseveration
Sorting Rules: -Color -Number -Shape 1. Explicit Instructions NOT Provided = Working Memory for Features Relevant on a Previous Trial 2. Rule Change after 10 Successful Trials = Flexibility/ Task Switching Patients with frontal lobe lesions cannot keep track of previous responses to inform current decision & perseverate when rules change
Brain Structures that Control Attention
Source of Attention -Which brain areas are involved in focusing attention based on current behavioral goals? -The Attentional Control Network Leads to Sites of Attention -Neural activity is modulated in specialized cortical processors depending on task demands Basic Idea: Projections from the Attentional Control Network contact neurons in specialized cortical areas and alter their excitability
How did the PFC-Supported Filtering Operations task work? What were participants instructed to do?
Task: Produce a single verb, an action performed, by or with each item; semantic (conceptual knowledge) demands are equated for items that require high/low filtering
Feature Integration Theory
The idea that spatial attention is required to bind component parts of a perceived object.
More Than One Type of Decision System?
The laboratory is an artificial environment.In other words, do I continue to exploit the resources at hand or set out to explore in hopes of finding a richer niche? They hypothesized that such decisions require a decision variable, a representation that specifies the current value of leaving a patch, even if the alternative is relatively unknown Similar to what we saw in the discussion of foraging, ACC activation is predictive when there is conflict between one option or another—a hypothesis we will return to later in this chapter
value
The lightness or darkness of a color
What is post-error slowing?
The tendency for response times to slow down following an error, but this rarely results in more accurate responses.
perseveration
The tendency to persevere in, or stick to, one thought or action for a long time
Which structure is most associated with a gating of visual sensory information?
The thalamic reticular nuclei
voluntary attention
The volitional, or intentional, focusing of attention on a source of input, train of thought, or action
Prefrontal Cortex and Modulation of Processing
The work just described reveals that the task goal, specified by the instruction, can modulate perceptual processing by either amplifying task-relevant information or inhibiting task-irrelevant information At present, we can only speculate on such hypotheses
PFC-Supported Filtering Operations
Thompson-Schill, et al. -Several Associates must filter out competing responses and select one -One Dominant Associate same response given by everyone; no need for filtering -Task: Produce a single verb, an action performed, by or with each item; semantic demands are equated for items that require high/low filtering -Patients with L. Inferior Frontal damage made more errors, but only when selection demands were high Failure to filter out irrelevant/suboptimal responses Follow-up Investigation Two Semantic Tasks 1. Verb generation 2. Color generation Subsequent Runs Same Task or Alternate Task = Alternate > Same: Prefrontal Cortex = Alternate = Same: Temporal LobeHigh Filtering > Low Filtering: Activity in the Inferior Frontal Gyrus sensitive to selection demands Verb Generation > Baseline: Activity in the Temporal Lobe sensitive to semantic retrieval PFC applies a dynamic filter that permits information selection based on current task requirements
Attentional Control Networks
Thus far, we have been considering the influence of attention on sensory processing; in other words, we have been looking at the sites of attention's influence Current models of attentional control suggest that two separate cortical systems are at play in supporting different attentional operations during selective attention: a dorsal attention network, concerned primarily with voluntary attention based on spatial location, features, and object properties; and a ventral attention network, concerned with stimulus novelty and salience These models are based on behavioral studies in healthy persons or in patients with brain lesions, as well as on the results of neuroimaging and electrophysiology experiments Current evidence suggests that two separate frontoparietal cortical systems direct different attentional control operations during orienting: a dorsal attention network, concerned primarily with orienting attention, and a ventral attention network, concerned with the nonspatial aspects of attention and alerting The two systems interact and cooperate to produce normal behavior The dorsal frontoparietal attention network is bilateral and includes the superior frontal cortex, inferior parietal cortex, superior temporal cortex, and portions of the posterior cingulate cortex and insula The ventral network is strongly lateralized to the right hemisphere and includes the posterior parietal cortex of the temporoparietal junction and the ventral frontal cortex made up of the inferior and middle frontal gyri In addition, there are subcortical networks that include the superior colliculi and the pulvinar of the thalamus
Ensuring That Goal-Oriented Behaviors Succeed
Tim Shallice and Donald Norman proposed a psychological model of cognitive control, outlining the conditions under which the selection of an action might require the operation of a high-level control system, or what they referred to as a supervisory attentional system If this is a well-learned process, there should be a means for signaling deviations from the expected course of events The medial frontal cortex, including the anterior cingulate cortex, is thought to be a critical part of a monitoring system, identifying situations in which cognitive control is required Error-related or feedback-related negativity signals are event-related potentials that occur when unexpected feedback is produced -This response is generated by the medial frontal cortex -The medial frontal cortex is engaged when response conflict is high -Through its interactions with lateral regions of the prefrontal cortex, a monitoring system can regulate the level of cognitive control
According to Grinband et al., 2008, ACC is sensitive to ______, even when the task itself is simple (no errors) and without conflict.
Time on task
Describe how the MEG Investigation: Color & Motion task works?
To compare information about color and motion direction in invasive and non-invasive signals, we presented rapid streams of dynamic random dot kinematograms with varying color and motion direction to macaque monkeys and humans We measured single-unit activity, analog multi-unit activity and local field potentials from multiple microelectrodes in six areas of two macaques, and MEG in eleven human volunteers In order to establish a link between these data that differed both in species model and measurement technique, we developed non-invasive, human-comparable macaque EEG We used custom-made 65-channel caps with miniaturized EEG electrodes to measure scalp-EEG in two animals This data, matching the invasive recordings in terms of species and the human MEG in terms of signal scale, allowed to relate circuit-level activity to large-scale measurements in humans After preprocessing, we treated all data types identically and submitted them to the same multivariate pattern analysis of visual information We used multi-class LDA and a cross-validation scheme to derive time-resolved confusion matrices For each combination of two stimulus classes A and B, the confusion matrices indicate the average probability of the LDA to assign a trial of class A to class B From this, we extracted information time courses, latencies, and tuning properties
Someone is diagnosed with unilateral neglect on the right side of their brain. What/where would you expect a deficit?
Trouble directing attention to the left side of visual space
True/False Consistent with the proposal that attention can be directed not only to spatial locations but also to objects, Egly and colleagues reported that a target was detected more quickly if it was presented within the boundaries of a cued object than when it was presented in a different object, even though neither target appeared in the cued location.
True
True/False Consistent with the proposed role of FEF as a controller of attention, it has been reported that electrical stimulation of FEF cells increases the firing rate of V4 cells when a preferred stimulus is presented in the shared receptive field of these cells.
True
True/False Extinction occurs when patients fail to report a contralesional stimulus in the presence of a competing ipsilesional stimulus. Nonetheless, research by Vuilleumier et al. (2002) indicates that extinguished objects are identified more quickly in a fragmented picture recognition test than novel objects, an outcome that suggests extinguished objects were processed despite the absence of awareness.
True
True/False In a dual-tasking experiment, participants held numbers in working memory while they attempted to process the names of pop-stars or politicians, ignoring the faces on which the names were superimposed. Activity increased in both lateral PFC and FFA when the working memory task was more difficult.
True
True/False Neuroimaging work suggests that learning a new rule by trial and error in the Wisconsin Card Sorting Task is associated with BOLD signal changes in bilateral inferior frontal sulcus; patients with frontal lobe damage cannot learn a new rule and continue to make the same response, or perseverate.
True
True/False Observations of medial frontal cortex activity sensitive to the duration of a simple visual stimulus (i.e., a static checkerboard) are problematic for the response conflict hypothesis of MFC function
True
True/False Research conducted by Rao et al. (1997) in monkeys indicated that the firing rates of individual neurons in the prefrontal cortex code are sensitive to specific locations ("where") and/or to specific objects ("what") that must be actively retained in the delayed-response task.
True
Where is the gate for attention to color?
V4
When attending to object features such as color, activity increases in ________, which is a ________ of attention.
V4 / site
________, important for color processing, is one of several brain areas best described as a site of attention. In contrast, structures in the ________ network, said to be the drivers of goal-directed attention, are best described as a source of attentional control.
V4/ dorsal attention
Ventral Attention Network
Ventral attention network is engaged when physically salient or unexpected events occur
orbitofrontal cortex
a region of the brain in which impulses involving excretion, sexuality, violence, and other primitive activities normally arise
Voluntary Visuospatial Attention
Visuospatial attention involves selecting a stimulus on the basis of its spatial location Effects of visuospatial attention can be seen in both the cortex and the subcortex CORTICAL ATTENTION EFFECTS -Neural mechanisms of visuospatial attention have been investigated using cuing methods combined with ERP recordings -The first big ERP wave has a positive polarity, begins following a latency period of 60 to 70 ms after stimulus onset, and peaks at about 100 ms over the occipital cortex contralateral to the visual hemifield of the stimulus -Taken together, these clues suggest that the P1 wave is a sensory wave generated by neural activity in the visual cortex and that, therefore, its sensitivity to spatial attention supports early-selection models of attention -Responses of single neurons were recorded and compared under two conditions: when the monkey attended the preferred stimulus at a specific location, and when it instead attended the non-preferred stimulus that was located a short distance away -Recall from Chapters 5 and 6 that many stages of neural processing take place within a visual area, and that in V1, different neurons display characteristic receptive-field proper ties; some are called simple cells, others complex cells, and so on -They found that spatial attention enhanced the responses of the simple cells but did not affect the spatial or temporal organization of their receptive fields, which remained unchanged over the trials -One prominent model, proposed by Robert Desimone and John Duncan, is known as the biased competition model for selective attention -This model may help answer two questions.In the biased competition model, the idea is that when different stimuli in a visual scene fall within the receptive field of a visual neuron, the bottom-up signals from the two stimuli compete like two snarling dogs to control the neuron's firing -To do this, they first asked whether, in the absence of focused spatial attention, nearby stimuli could interfere with one another -One may extend this idea to hypothesize that attention to yet other aspects of task-relevant visual stimuli would be supported by modulations of processing in visual areas tuned for those stimulus attributes; we will return to this idea later in the chapter, when we discuss feature and object attention SUBCORTICAL ATTENTION EFFECTS -Could attentional filtering or selection occur even earlier along the visual processing pathways—in the thalamus or in the retina? -These projections synapse on neurons in the perigeniculate nucleus, which is the portion of the thalamic reticular nucleus that surrounds the lateral geniculate nucleus -So, highly focused visuospatial attention can modulate activity in the thalamus -Well, we know from other work that the TRN neurons synapse onto the LGN neurons with inhibitory signals.he latter mechanism is consistent with the increased neuronal responses observed for the neurons in LGN and V1 when coding the location of an attended stimulus
When Does Attention Affect Processing?
Voluntary Attention: Cortical Processing The physical stimulus is exactly the same but the amplitude of the P1 ERP waveform is greater when attention is at the target location Voluntary Attention: Endogenous Cueing The time-course of this effect is consistent with early selection because time-course matches arrival of fist signals in V1 Hopfinger & Mangun Reflexive Attention: Exogenous Cueing Attention Capture, faster target detection, if the delay is short Inhibition of Return, slower target detection, if the delay is long -Perceptual processing at the cued location is thought to be enhanced Does P1 amplitude increase when attention is captured? -Reflexive attention transiently upregulates visual processing where attention is captured Visual Search Tasks Attention is deployed in a spatially-specific manner during search and engages the same visual-spatial attention system
Where Does Attention Affect Processing?
Voluntary Attention: Subcortical Processing Inhibitory TRN neurons reduce signal transmission to Visual Cortex when visual inputs are to be ignored
Mary is painting in her studio with the radio on. She is looking at her pallet, mixing colors to create the perfect shade of chartreuse, when suddenly an emergency warning plays on the radio pulling her attention away from the task at hand. In this example, Mary's attention to the paint is best described as ________, while attention to the radio is ________.
Voluntary attention/ reflexive attention
Endogenous Attention
Voluntary deployment of attention to a particular object or spatial location.
Processing and Awareness in Extinction
Vuilleumier, et al. Is visual information contralateral to the lesion processed without awareness? -Implicit Fragmented Picture Recognition Degraded pictures are identified more quickly if the were presented and extinguished than if they were new; the same items that show this facilitation were not explicitly recognized as part of the set that had been seen
Dopamine Activity and Reward Processing
We have seen that rewards, especially those associated with primary reinforcers like food and sex, are fundamental to the behavior of all animals Much of the work on reward has focused on the neurotransmitter dopamine Dopaminergic neurons that originate in the VTA project through two pathways: The mesolimbic pathway travels to structures important to emotional processing, and the mesocortical pathway travels to the neocortex, particularly to the medial portions of the frontal lobe A key challenge to the reward hypothesis came about when investigators recognized that the activation of dopaminergic neurons was not tied to the size of the reward per se, but was more closely related to the expectancy of reward This observation led to a new view of the role of dopamine in reinforcement and decision making DOPAMINE AND PREDICTION ERROR -We know from experience that the value of an item can change -Rather than thinking of the spike in DA neuron activity as representing the reward, he suggested it should be viewed as a reward prediction error, a signal that represents the difference between the obtained reward and the expected reward -First, consider the reduction in the dopaminergic response to the juice -Now consider the increase in the dopaminergic response to the light -Although this effect might occur for many reasons, the impressive thing is that it is predicted by a simple model in which value representations are updated by a simple mechanism based on the difference between the predicted and obtained reward REWARD AND PUNISHMENT -Not all options are rewarding; just consider your dog's response after he has tried to nudge a porcupine out of a rotting tree -The habenula, a structure located within the dorsal thalamus, is in a good position to represent emotional and motivational events because it receives inputs from the forebrain limbic regions and sends inhibitory projections to dopamine neurons in the substantia nigra pars compacta -Habenula neurons became active when the saccade was to the no-reward side and were suppressed if the saccade was to the reward side -DA neurons showed the opposite profile: They were excited by the reward-predicting targets and suppressed by the targets predicting no reward -A region in the insula also responded to prediction error, but only when the choice resulted in a loss
Older adults using NeuroRacer to "train their brains" showed improvements
When completing both single-task and multi-task training, although multi-task training provided greater and longer-lasting gains.
According to the Biased Competition Model, what statement is FALSE about Receptive Fields and attention?
When the receptive field size is large, competition is unlikely to occur and attention is easily directed as intended.
Reflexive Visuospatial Attention
While we can voluntarily direct our attention to the words on this page or to remembering what we had for breakfast, oftentimes things in the environment attract our attention without our cooperation These studies examine how a task-irrelevant event somewhere in the visual field, like a flash of light, affects the speed of responses to subsequent task-relevant target stimuli that might appear at the same or some other location This method is referred to as reflexive cuing or exogenous cuing, because attention is controlled by low-level features of external stimuli, not by internal voluntary processes Although the light flash "cues" do not predict the location of subsequent targets, responses are faster to targets that appear in the vicinity of the irrelevant light flash—but only for a short time aft er the flash, about 50-200 ms These effects tend to be spatially specific; that is, they influence processing in and around the location of the reflexive cue only This phenomenon is called the inhibitory after effect or, more commonly, inhibition of return—that is, inhibition of the return of attention to that location Presumably, the neural networks implementing these attentional modulations of sensory analysis are different, reflecting the differing ways in which attentional control is triggered for the two forms of attention
Multitasking
While you are reading this chapter, are you occasionally shifting your attention to reading email, texting friends, surfing the Web, listening to music, or glancing at a televised game? This study suggests that the term multitasking may be a misnomer: What we really do is alternate between tasks, and with practice we can become quite proficient in task switching
Attention: Basic Concepts
Williams James -Everyone knows what attention is -It is the taking possession by the mind, in clear and vivid form, of one out of what seem several simultaneously possible objects or trains of thought -Focalization, concentration of consciousness are of its essence -It implies a withdrawal from some things in order to deal effectively with others Attention can be Deployed Voluntarily i.e. taking possession by the mind Attention is Selective i.e. one out of what seem several simultaneously possible objects or trains of thought Attention has Limited Capacity i.e. implies a withdrawal from some things in order to deal effectively with others
Monkeys with lateral PCF lesions are impaired on the _____ Memory Task and are not impaired on the _____ Memory Task.
Working / Associative
The Benefits and Costs of Goal-Based Selection
You are given a candle, a box of matches, and some thumbtacks The juvenile mice learned more quickly than the adult mice—a result reminiscent of the novel problem-solving abilities of patients with frontal lobe damage
In an experiment where a face and a house were superimposed onto one another and both were semi see-through, activation in the FFA will be driven up when.
You're attending to the face or moving features that happen to be the face.
feature integration theory of attention
a psychological theory of visual perception based on the idea that the visual system can process in parallel elementary features such as color, shape, and motion, but requires spatial attention to bind the features that define an object
dynamic filtering
allows firewall to react to emergent event and update or create rules to deal with event
inhibitory control
an ability to display acceptable conduct by resisting the temptation to commit a forbidden act
reflexive cuing
another name for exogenous cuing
normative decision theories
attempts to define how people should make decisions
descriptive decision theories
attempts to predict how people actually make choices, not to define ideal choices
exogenous attention
automatic attraction of attention by a sudden visual or auditory stimulus
goal-oriented actions
based on the assessment of an expected reward or value and the knowledge that there is a causal relationship between the action and the reward
ventral attention network
bottom up, exogenous attentional control
anterior cingulate cortex
brain region that monitors our actions and checks for errors
Voluntary attention is also known as______, and reflexive attention is also known as_________.
endogenous attention/exogenous attention
We would expect a patient with frontal lobe damage to have trouble completing a task involving:
changing sets of rules
The Exogenous Attention System has a built-in safety mechanism to prevent constant reflexive responses to locations that have captured attention. This mechanism is called ________.
inhibition of return
reward prediction error
discrepancy between predicted and currently experienced reward of particular event
utilization behavior
impulsively acting on irrelevant objects in the environment
temporal discounting
in decision making, the greater weight given to the present over the future
When faces are presented in a task but should be ignored, and PFC is occupied with a difficult working memory task, activity in FFA _______.
increases
dopamine
influences movement, learning, attention, and emotion
bottlenecks
occur when resources reach full capacity and cannot handle any additional demands; they limit throughput and impede operations
prefrontal cortex
part of frontal lobe responsible for thinking, planning, and language
selective attention
the focusing of conscious awareness on a particular stimulus
