PSYC 382 Exam 3
In what ways is the initiation of behavior often compromised in individuals who have frontal lobe brain damage? Behavior initiation appears to be most reliant on which specific region of the frontal lobe?
- psychological inertia = (inertia, it terms of phsyics, is the tendency for a body at rest to stay at rest unless it is acted upon by an outside force. resistance/disinclination to motion/action/change) in psychological terms, it is the resistance to action/taking action. patients with executive dysfunction are poor at starting an action or a behavior, and great difficulty stopping it if initiated. case study of stopping personal hygiene, reduction in speech and spontaneous conversations. patients with damage to medial frontal regions including the supplementary motor area and anterior cingulate, show differential difficulty in responding quickly compared to patients with damage in other frontal regions (these areas are involved in motor planning and selection). in patients with dimensia, the larger the atrophy in gray matter in the cingulate, the greater the difficulty in initiating behavior medial prefrontal cortex may be involved in how much "effort" exerted to reach a goal - rats who have lesions to the ACC do not tend to engage in actions that, although effortful, would lead to high rewards. (ACC is not only involved in goal-orienting movements, but also the amount of effort required to reach that goal). in human studies, the more effort required, resulted in higher activity in the dorsal regions of the ACC and pre-SMA. people with damage to these areas might think that it is not worth the effort.
Make sure you can describe the consolidation and multiple trace theories
1) Ribot's consolidation theory - Retrograde amnesia is more likely for recent events, and even as the amnesia fades over time, the most recent events are affected for the longest time, sometimes permanently. This suggests these items have undergone an initial consolidation process but not completed a slower permanent consolidation process. 2) Standard consolidation theory - a memory is bound together in the hippocampus and then through some interaction between the medial temporal lobe and the neocortex, the ability to retrieve the bound information is slowly transferred to the neocortex until the hippocampus is no longer needed. (consolidated memories lie in the neocortex) multiple trace theory = the long-term stores for semantic information rely solely on the neocortex, while episodic memory, consolidated or not, continues to rely on the hippocampus for retrieval. Every time an episodic memory is retrieved, a new memory trace is set in the hippocampus. The more times a memory is retrieved, the more traces are set down. This suggests that episodic memories degrade over time and are slowly converted into semantic memory. Therefore partial hippocampal damage would partially affect episodic memory but complete damage would completely destroy it.
brain systems for different stages of memory
1. memory has to be created - MTL regions (hippocampus, retrosplenial cortex parahippocampal gyrus (both important for spatial information), perihinal cortex (object information and identity), and both this spatial and object information converge on the entorhinal cortex which is involved in the representation of amodal semantic info. all this info is then transmitted to the hippocampus.) hippocampus helps by ensuring highly similar and overlapping representations are encoded in a way that makes them more distinct. - prefrontal regions subsequent memory effect shows higher activity in both these brain regions at encoding than items that are not remembered 2. memories have to be stored and maintained over time 3. while they are stored they must undergo consolidation (strengthening) 4. for memory to be useful, need to be able to retrieve it.
what are the three subregions of the amygdala and what other structures do they connect with?
3 main subdivisions:1. basolateral nuclei --> project to hippocampus and PFC, also regions involved in reward and punishment (allows amygdala to influence learning and memory esp. related to reward)2. Central (cortical) nucleu and corticomedial nuclei --> project to hypothalamus, brain regions involved in autonomic and hormonal responses (allow emotional modulation of these responses)
What are some possible roles for the ACC and medial PFC in detecting and correcting errors? Make sure you're aware of some of the alternate explanations I briefly discussed, such as computing effort and goal outcome
ACC: a variety of evidence suggest the ERN component arises from the rostral regions of the anterior cingulate. one initial suggestion was the ACC actually detects the error. other evidence suggests that even when a person is unaware of the error, the ERN can still be detected. medial prefrontal cortex: - its role in detecting and correcting error errors is under debate - one viewpoint is that mPFC does not detect errors so mach as it monitors for conflict - it is linked to error detection because errors usually occur when there is conflicting info - when cingulate detects conflict, it signals to the DLPFC to ramp up top-down control so as the reduce conflict and errors in subsequent behavior. - mPFC determines whether exerting control is worth the effort and cost in a given situation. Ex. evaluating and rehearsing what you are going to say before you say it - if you're with friends, you probably don't monitor this as much but if you're in a job interview the cost is worth it. - other models suggest cingulate is focused on determining whether the action you just took look leads to a useful or good outcome (mPFC is sensitive to NEGATIVE outcomes or the loss of rewards) - others argue cingulate calculates difference between expected outcome of an action and the actual outcome regardless of whether it is + or -. the history of the outcomes of a person's actions serve as a guide to prevent future errors. ERN may reflect the subjective evaluation performance ("I just messed up and didn't get what i wanted") rather than whether an error was actually made. It can be influenced by mood, distress, and is amplified in OCD patients, larger when an error leads to monetary loss - different regions of cingulate may be involved in prediction of the outcome of an action as compared to the evaluation of the outcome. prediction is thought to be generated by pregenual and posterior regions of ACC and evaluation outcome is performed in the region in-between that extends into SMA.
some unitary models implicate other brain regions in executive function; however, most look at the PFC as the driving neural mechanism. what do we mean by a unitary system? what role does the PFC play in such a system?
AI susggest that researching a goal requires the creating of a hierarchy of simpler and more solvable subgoals. Frontal lobe damage disrupts this ability to create a hierarchical goal list. this view suggests frontal lobe supports executive function in relatively undifferentiated manner. a unitary system = there is a multiple demand system utilized for executive processing across many different domains including language, memory, and math. the frontal lobes are involved in this, as well as other brain regions. other unitary models emphasize the role of the prefrontal cortex in providing biasing signal to other brain systems depending on the current goal and context. (the system being driven by the prefrontal cortex is an all-puprose system (un executive function) in that it guides activity in the rest of the cortex across a range of systems and processes (sensory, memroy, emotion, response processes, etc). it is the main driver when it comes to executive control across all these processes and allows us to enable and meet our goals (much like setting the switches on a train track). this model also emphasizes the role of profrontal cortex in maintaining the task goal. patients with prefrontal damage aside from perseveration generally have disorganized behavior.
What is the role of the amygdala in recognizing facial expressions. Know the Adolphs and Whalen experiments
Adolphs - S.M never really looks at the eyes whereas the controls look at the T region (eyes, nose, lips--eyes in particular). Found that there was no difference between S.M and the controls in recognizing non-fearful expressions, but S.M. did worse for fear expressions. However, when S.M was told to look at the model's eyes they recognized fearful expressions at the same rate as the control. Whalen - amygdala is responsive to specific facial features that indicate fear such as enlarged whites of the eyes. Amygdala damage might lead to inability to recognize these ques. This experiment showed an image of a fearful expression with more whites exposed and a happy expression with less eye whites. Found that fearful eye whites alone (with black background only) induce an increased response above baseline in the left ventral amygdala. Hadj-Bouzaine - monkeys w/o lesions, expressive faces --> increased activity in amygdala and inferotemporal cortex compared to neutral faces. in monkeys with amygdala lesions, inferotemporal cortex did not show enhanced response for emotional v. non-emotional faces even though there was an enhanced response for faces compared to nonfaces. Therefore, amygdala is critical to IT cortex heightened response to emotionality of a face.
How can memory be modulated by emotional experiences?
Cahill et. al - participants were presented with a series of slides that told a story of two alternative narratives. One told the story of an emotionally charged event such as a mother and son in an accident and the other was a neutral story about a safety drill. There is a delayed memory test after this story. Neurologically healthy individuals showed selective enhancement of memory recall for the emotional story compared to the neutral story. People with amygdala damage did not show this enhanced memory for the emotional story but showed no difference in recall for the neutral story compared to the controls. amygdala is thought to respond to emotional situations that are highly arousing. when it becomes active, it influences portions of the memory circuitry in the brain such as the hippocampus and striatum. This mechanism is obviously advantageous (evolutionarily speaking).
(From the book) section 10.10: What are the processes involved in emotional regulation (understand Ochsner's model and Gross's model)
Gross = emotions may be regulated by either manipulation the input to the system (antecedent-focused emotion regulation) or the system's output (response-focused emotion regulation) Ochsner = cognitive control regions mediating repparaisal (the PFC) would modulate regions involved in appraising the emotinoal qualities of a stimulus (amygdala). Thus, cognitive upregulation would be associated with greater activation of the amygdala, and downregulation would be associated with less.
Basal ganglia's role in implicit/procedural learning, which usually occurs gradually and incrementally through repetition of motor, perceptual, or cognitive operations, and which leads to improved performance. How does this learning occur? Make sure you understand that the basal ganglia most likely drives procedural learning by aiding in the linkage of sensory information to the motor outputs, actions, or choice required to exhibit such learning.
Healthy patients usually show increases in striatal activity during skill learning (Parkinson's and Huntington's patients do not). The role of the striatum in implicit/procedural learning is not restricted to the motor domain--also impaired on probabilistic learning tasks (ex. weather prediction task - over 50 trials, neurologically intact people show significant improvement with their weather prediction (through TRIAL AND ERROR) performance while Parkinson's patients did not; IMPORTANT--patients with amnesia due to hippocampal damage also improved on this task); shows striatum is important for implicit/procedural learning in the motor AND cognitive domains Basal ganglia associations are made between the stimulus and its response
(From the book) section 10.2: Know the role of multi-voxel pattern analysis. What does this methodology tell us about emotion and neural activity/networks?
MVPA - takes into account the relationships between multiple voxels (as opposed to the more common approach, which considers each voxel separately). this helps recognize patterns and identify neural "signatures" of different emotions.
(From the book) section 10.9: understand the conditioned fear experiments involving S.P
S.P had bilateral amygdala damage and was shown a blue square which the experimenter periodically presented for 10 seconds. During acquistion phase, they received mild shock after the blue square was presented. She had normla response to shock but no change in response when she saw the blue square even after several trials. even though she knew she was going to get shocked
identify the important components of the models in ch 12 (in Shallice's model, understand contention scheduling and the supervisory attentional system - understand perservation based on these two processes described in Shallice's model) (Stuss and Benson - describe the hierarchical processes and the brain areas associated with those processes - how might their model explain deficits in cognitive control, such as perservation?)
Shallice - 2-component system influences the choice of behavior - part 1: contention scheduling = a cognitive system that enables relatively automatic processing, which has been learned over time - part 2: supervisory attentional system = cognitive system required to effortfully direct attention and guide action through decision processes theory is that frontal lobe damage disables the supervisory attentional system leaving actions to be governed totally by contention scheduling few deficits are observed in fairly routine situations in which the appropriate response is evoked by a stimulus in a simple and obvious way (ex. provide a definition for a word - often familiar and well-practiced) when a stimulus is novel and requires flexibility, frontal lobe damage patients have trouble because no schema (series of behaviors) is available in contention scheduling. the patients appear disinhibited with an inability to control behavior or urges especially those that are considered inappropriate in a social setting. this behavior can sometimes be triggered by stimuli in the environment referred to as ENVIRONMENTAL DEPENDENCY SYNDROME - when supervisory attentional system is lost, the typical schemes of contention scheduling get invoked automatically (as if their actions are impelled or obligated by their physical environment) This syndrome is often expressed in different forms depending on the person's personal history prior to damage. Cases of patients with "executive dysfunction" attending a buffet dinner hosted by the physician they were working with: man from upper class background took a seat and expected to be served (even though it was a serve yourself buffet). the other, a former housekeeper, immediately starts serving the other guests. - example: a man seeing a hammer and nail, hangs a painting in someone else's house - a woman starts to dry dishes unasked in someone else's home patients with frontal lobe damage often exhibit PERSERVATION = repeating the same action (or thought) over and over again. once a very strong trigger in the environment activates a scheme or action, this behavior will continue to be invoked until an incompatible process is activated. (difficult to interrupt) Stuss and Benson: frontal lobes are especially important in regulating behavior in nonroutine situations or in situations in which behavior must be carefully constrained. model links the degree of control to particular neural substrate in a hierarchical manner - lowest level = sensory info and simple tasks are processed by posterior regions of the brain in a relatively automatic manner that varies little from day to day (difficult to exert conscious control over this) - next level of control = associated with the executive, or spervisory functions of the frontal lobe - lower level sensory info gets adjusted so behavior can be guided to a specific goal. control of efforts here is very slow and requires a great degree of conscious control. - highest level = self-reflection and metacognition self-reflection = allows an individual to have self-awareness and to understand the relationship of the self to the environment metacognition = ability to reflect upon a cognitive process (how well you are able to remember the process of say studying information). allows us to develop an abstract representation of the world and how we act in the world. this model explains deficits in executive function by arguing that the organization of behavior is one of the main functions of frontal regions. explains deficits in dealing with novelty and lack of cognitive flexibility because the frontal lobes are assumed to be important for nonautomatic behavior. the inability to self-criticize or self-monitor resulting from prefrontal cortex damage could be explained by this model as patients would be left devoid of any ability to reflect upon themselves or the processes in which they become engaged
What role does the dopaminergic cells of the basal ganglia play in learning? Specifically, how do they support error driven learning?
The release of dopamine can serve as a learning signal--when an animal receives a reward that is unexpected, dopaminergic cells show large increase in firing. But if a reward is expected and the reward occurs, there is not much of an increase in firing. If a reward is expected but does not occur, the firing rate is significantly lower, signalling to the animal to change behavior ^^ERROR DRIVEN LEARNING
Make sure you understand the task switching paradigms: Wisconsin - They switched on their own when they realized the way they are categorizing the cards is incorrect Task-set similarity task - Task is switched based on a rule change
Wisconsin Card Sorting Test = participants are shown cards with different numbers of different shapes of different colors. participants are not told on what dimension (number, shape, color) the cards should be sorted. as the individual places a card beneath on the of the 4 cards presented in the category they believe it goes they are only told whether it is the correct or incorrect response. after the participant correctly sorts 10 cards on the basis of one dimension, the experimenter will change the criteria to another dimension without telling them. neurologically healthy people quickly realize that their behavior previously no longer leads to a correct response and they adjust their responses accordingly. In contrast, people with executive dysfunction PERSEVERATE and will continue to place the cards based on the attribute they did earlier (even after it switches and they get negative feedback). if they are asked to think aloud, they say they know that they're not doing it right and that it is wrong but they cannot change it. This test results in activity in the DLPFC, ventrolateral PFC, inferior parietal lobe, temporoparietal association cortex and basal ganglia. this diversity indicates the high complexity of this task. (must be able to switch categories, create a rule that they keep in memory that will guide sorting and the memory of prior trials, deductive reasoning). even normal people have trouble (there is a cost) switching between tasks. this cost is difficult if not impossible to eliminate. task-switching is likely to be directed by an executive control system that is independent of the systems that actually perform each of the individual tasks. repeat trials = perform same task as on prior trial switch trials = person performs different task than on previous. response times are longer for switch trials than form repeat trials (this is known as the SWITCH COST) the increase in response time reflects: 1) need to inhibit or overcome the prior task set (task-set inertia) 2) need to configure the system for the current task set. one manipulation in this study is to vary the time between when the cue is given and when the stimulus appears. if you increase the time in this interval, it reduces the switch cost. This is probably because you are given more time to configure for the new task before you have to make a decision. But even with long delays, there is still a switch-cost. it is IMPOSSIBLE to eliminate it. there is also evidence that task-set inertia contributes to switch-cost. Task-set similarity task = individuals are first taught to discriminate between two items (abstract shapes of the same color) and they have to respond to only one of them. When they respond, another image is superimposed over both shapes (usually a white abstract shape) and they have to ignore the white shape over it and select the image with the chosen shape. after many trials, the two shapes you were distinguishing between are switched to new shapes with new white objects over them. eventhough it is the same task, they switched the shapes = INTRADIMENSIONAL SHIFT TRIALS / INTRADIMENSIONAL SWITCH CONDITION) still the same dimensions, but they just switch the type within. after this trial, there is the EXTRADIMENSIONAL SHIFT TRIAL. they are now asked to distinguish between the superimposed white images and ignore the shapes beneath it. (switch the target) individuals with frontal lobe damage are deficient in the extradimensional switch but not the intradimensional shift. there is also greater activity in the prefrontal cortex extradimensional. can think of it as the frontal lobe is only required to switch to a strategy different from the original one.
Role of the amygdala in fear conditioning, linking events and stimuli to a fearful experience. Make sure you can identify/explain Pavlovian conditioning
amygdala helps associate a stimulus with emotional responses; it mediates the learning and expression of emotional responses to stimuli whose emotional significance is not automatic but has been learned via association, and it allows emotional experience to modulate certain aspects of long-term memory Pavlovian fear conditioning = when a stimulus comes to evoke fear when it is paired with an aversive event. (e.g. tone is paired with a foot shock. rat comes to fear the tone because it associates it with the shock. fear is expressed by changes in autonomic responses such as freezing, increases in blood pressure, etc.) Animals with lesions in the lateral amygdala show dramatically reduced conditioned autonomic and motor responses to the tone (less likely to show fear) contextual fear conditioning - fear response is selective to the context/environment in which conditioning occurs. (e.g. putting rats in the chamber where conditioning has occurred makes them freeze even before the tone. in a different environment, don't freeze until tone is presented). Amygdala lesions also block this conditioning as in Pavlovian
(From the book) section 10.3/10.4: Theories and cognitive considerations of emotion
basic emotions = closed set of emotions, each with unique characteristics, carved by evolution and reflected through facial expressions. complex emotions = combinations of basic emotions some of which may be socially or culturally learned that can be identified as evolved long lasting feelings dimensional theories of emotion = emotions that are fundamentally the same but that differ along one or more dimensions, such as valance (pleasant to unpleasant, positive to negative) and arousal (very intense to very mild) in reaction to events or stimuli. every theory of emotion generation is an attempt to explain the physiological reaction (for instance, the racing heart), the behavioral reaction (fight or flight response) and the subjective experiential feeling ("I;m scared!")
What is the interaction between the hippocampus and amygdala? Dissociations, how the amygdala modulates the hippocampus during arousal, the effect of encoding and decay
bi-directional interactions between hippocampus and amygdala allow them to influence one another's activity. - input from the amygdala to the hippocampus can allow emotional meaning of a stimulus (coded by amygdala) to influence the encoding and consolidation of that info by the hippocampus - memory enhancement effect = the greater emotional intensity associated with an event or experience, the better it is remembered (amygdala damage interferes with this) - amygdala increases learning/memory efficiency in the hippocampal-striatum complex (able to increase the efficiency of learning in these networks under emotionally charged conditions) - emotion enhances encoding processes and makes memories less prone to decay over time
What is memory consolidation? Make sure that you generally understand how the effects of retrograde and anterograde amnesia change over time
consolidation is the process that stabilizes a memory over time after it is first acquired. One theory for how this occurs involves retrograde amnesia. Ribot's law proposes that retrograde amnesia tends to be greatest for most recent events and describes a theory of system consolidation with a temporal gradient. Retrograde amnesia is more likely for recent events, and even as the amnesia fades over time, the most recent events are affected for the longest time, sometimes permanently. This suggests these items have undergone an initial consolidation process but not completed a slower permanent
how does the ventrolateral and dorsolateral PFC aid in encoding memories?
dorsolateral PFC (Which we later learn is implicated in self-monitoring and self-evaluation) was active in both cases of self-focused reappraisal (downregulation negative emotions (make a negative situation better) and upregulating negative emotions (making a bad situation worse)
Generally speaking, are there hemispheric differences in planning and sequencing? If so, what are they? Is there a region of the brain that integrates this hemispheric processing?
each hemisphere plays a somewhat complementary role in planning and sequencing. left hem is more involved in creating subgoals, right hem more invovled in creating the relationships between those subgoals. ex. making pasta; left hem involved in setting subgoals (getting out the utensils, assembling ingredients, starting pasta, setting the table - have a specific order) and right hem is involved in what moves in between the goals are not necessarily needed but are required and monitoring the interrelationship between the subgoals. for example, if the pans are dirty and need to decide if you have time to put the dishes in the dishwasher or need to wash them by hand, right hem would decide based on time to the dinner which to do. the degree of interhemispheric white matter connecting left and right PFC regions predicts how well people perform on the task. In the Tower of London, greater activation in the left dorsolateral PFC when there was more empahsis on the logical sequencing of the subgoals. But when the subgoals required intermediate steps, more activation in the right dorsolateral PFC activity than left.
(From the book) section 10.1 : know core definitions of emotion, make sure you understand the difference between affect, mood, and emotion
emotion = neurological processes that have evolved to guide behavior in such a manner as to increase survival and reproduction. according to Izard, "Emotion consists of neural circuits (that at least are partially dedicated) response systems, and a feeling state/process that motivates and organizes cognition and action. Emotion also provides information to the person experiencing it, and may include antecedent cognitive appraisals and ongoing cognition including an interpreation of its feeling state, expressions or social-communicative signals, and may motivate approach or avoidant behavior, exercise control/regulation of responses, and be social or relational in nature." at the very least emotion intails a physiological reaction to a stimulus, a behavioral response, and a feeling. feeling = subjective experience of an emotion emotions are relatively short in duration and fall under the umbrella term of "Affect" which includes both discrete emotions with a short time-span and longer, more diffuse states such as chronic stress and mood. emotions are distinct from moods in that they often have identifiable objects or triggers. a "Mood" is a long-lasting diffuse affective state that is characterized by primarily a predominance of enduring
Is there a clean neural dissociation during error monitoring/correction? Explain.
error monitoring and evaluation systems in the brain are influenced by differences amongst people: - people who are anxious show an increased ERN with the relationship stronger for those who show a high level of worry while those not adept at monitoring and evaluating decisions such as people with substance use disorder or those with ADHD show decreases in the ERN and Pe. There is unlikely to be a one-to-one mapping between a particular piece of frontal cortex and a specific function such as self-evaluation. ACC is not sole error detector in the brain because some abilities relating to evaluation and monitoring are intact in people with ACC damange. Patients with cingulate damage are able to report errors but are slow in correcting them. damage to other regions (such as lateral PFC, insula) results in trouble with self-monitoring and evaluation. error evaluation can also be altered by damage to the basal ganglia. EEG recordings suggest a cascade of activity that occurs across a variety of brain regions that unfold over time as we make choices and act upon the world.
anterior temporal regions - amodal storage of semantic info
explicit/declarative memories can be divided into two types: episodic and semantic memory people with damage to the medial temporal lobe (hippocampal region) lose ability to form new memories about episodes in their lives, suggesting a disruption of episodic memory. however after brain damage they can learn some new semantic information, suggesting this type of info does not rely entirely on the MTL. Child case studies - despite amnesia for daily lives, could attend school, learn language, learn to read, etc. suggesting retrieval of semantic info may be somewhat possible without hippocampal system (although it cannot be separated i.e. the mechanism is not entirely independent but can be somewhat rewired if necessary) Anterior temporal lobe may play a role in retaining info that is not linked to a particular modality. it may serve as a convergence zone and integrate sensory input fro modality-specific regions to create an amodal representation info (doesn't link together events in a particular time like hippocampus). ex. sheep are farm animals that have wooly coat used for clothing. in semantic dimensia, people progressively lose ability to retain semantic info. most notable pathology shows significant damage in anterior temporal region.
Which brain regions are active during spatial and verbal analogical reasoning tasks?
in analogical reasoning tasks, such as the verbal analogy test, there is greater activity in the left DLPFC (implicated in working memory) and the frontopolar cortex (Implicated in higher-order relational processing) along with DLPFC and frontopolar cotex, the anterior insula and parietal cortex are engaged in analogical reasoning regardless of whether it is verbal or visuospatial there are distinct areas in frontopolar cortex that are activated for visuospatial analogies and seperate regions that code for semantic analogies (which tend to be verbal) anterior temporal regions involved in semantic processing may also be important for analogical reasoning as anatomical variation in these regions are associated with an individual's level of analogical reasoning
What are insight problems? Describe the EEG profile that we observe when participants are trying to solve an insight problem.
insight problem = the correct solution to a problem suddenly pops into one's mind ("Aha moment") EEG sugguest that prior to presentation of problems solved by insight, there is greater activity over right temporal areas associated with semantic processing and a burst of gamma activity from this region. suggested as one of the means by which info from different brain regions can be bound together to come to consciousness. Right hem involvement is no surprise because it is integrative in nature and semantic nature may allow for more diffuse and distant dissociations. Before insight occurs there is an increase in alpha activity which reflects the increased filtering out of sensory info so that it won't interfere with the ongoing processing of relatively weak and as of yet not formulated solution. (when you're trying to solve a problem, one may close eyes or cover their ears). tDCS studies show blocking activity in left frontal temporal regions them actually increase activity in right frontal temporal regions and problem solving in activities that require thinking outside of the box. reversing this results in no increased performance.
What changes in fMRI do we see in the amygdala during frightening or emotional situations?
larger amygdala activation associated with stronger conditioned fear response
How are multifactor models different from unitary models? how is a unity and diversity model different from your basic unitary model? what subprocesses did Stubs and Alexander propose based on their work with patients with executive deficits?
multifaction model = executive function may consist of seperable facets or factors unity and diversity model = executive function consists of one common factor required for all executive function (building of unitary idea) but then there are specialized funcitons required in specific situations. a common factor is required for all executive function and is thought to be the ability to maintain task goals, especially in the face of distractions. two more specific factors (only required under certain situations - represent diversity aspect) - first: shifting-specific executive function is the ability that allows us to switch from task to task (cooking onions, while boiling pasta) - second: working memory updating executive funciton allows the system to reset info in working memory such as required whem a subgoal has been reached and the system must move onto the next subgoal. Stuss and Alexander - suggest 3 types of executive abilities based on the pattern of deficits in patients with frontal lobe damage - one subprocess = drives initiating and sustaining a response, especially when such behavior is not triggered or dirven by environmental stimuli (rely on medial frontal regions) - second subprocess = task-setting, which enables a task to be chosen and provides the steps required to perform the task (left lateral regions of the frontal lobe) - final subprocess = monitoring, which is checking of behavior over time to ensure that it is being produced correctly, and to make any adjustment of behavior that might be required (right lateral regions of prefrontal cortex) executive function is one of the most complex abilities performed in the brain. regardless of the models, executive function can be considered a process that allows behavior to be effortfully guided to a goal, especially in nonroutine behaviors
be able to identify the structures of the limbic system?
papez circuit: hypothalamus, hippocampus, anterior thalamus, and cingulate cortex In addition, also include the amygdala, fornix and orbital frontal cortex
understand the role of the frontopolar cortex in maintaining multiple task sets simultaneously
patients with damage to lateral prefrontal regions in the left hem have difficulty in task setting (often wander or do something that has nothing to do with the task). neuroimaging studies show increased lateral prefrontal activity when a task is difficult to maintain such as the Stroop task. prefrontal areas help us stay on task, especially when irrelevant info is particularly distracting. if more than one task set needs to be maintained, frontopolar cortex (BA 10) is likely to play a role ex. when the phone rings and you're cooking dinner. researchers believe this area likely integrates processing for two or more separate operations for a higher goal. ex. it may help to process subgoals and then integrate info to determine if goals are being met. like if you are making dinner, need to integrate info to make sure goal is met. (is pasta cooked? is sauce ready? if so, met goal and dinner is ready) when people make selection of a task themselves, there is more activity in the dorsolateral PFC and in portions of the ACC. other studies have reported activity in frontopolar regions (which supports the idea that this area is involved in which of the potential task sets is to be employed.)
What evidence do we have that suggests that PFC is involved in selecting sequences or strategies that help us achieve a goal?
patients with frontal lobe damage are less likely to report that they use strategies, and that when they use a strategy it is often ill defined or invoked inconsistently. Patients with frontal lobe damage are inefficient and ineffective at the Tower of London task (take many moves to do it and are aimless to a certain degree). dorsolateral prefrontal activity is observed to an increasing degree with increasing difficulty of the task. performance on this task can be improved by tDCS (= transcranial direct stimulation; electrical activity through anodes and cathodes modulate brain activity) over lateral prefrontal regions (suggests bilateral importance of the prefrontal cortex)
Generally speaking, what behavior and brain activity do we see in neurologically healthy controls and people with frontal lobe damage?
people with left frontal lobe damage have specific deficit in task-switching, especially when there are no obvious cues as to which task should be performed and when. their difficulty occurs regardless of whether the switch involves a conceptual set or perceptual set. people with right inferior frontal lobe damage, there is an inability to exert inhibitory control which can make task switching even more difficult. the inability to maintain a task set can exacerbate the difficulty in task switching in patients with left dorsolateral PFC regions. overall, lateral prefrontal regions are important in task-switching, more specifically the inferior frontal junction (located at the base of the DLPFC and inferior frontal cortex), especially in reducing interference in task switching. however, there is not one particular area of the brain that flips the switch. task switching invovles coordination over frontal regions and parietal lobe regions regardless of the particular tasks being performed. in monkeys, there is synchronous activity in the frontal and parietal lobes during task-switching. also activation in fronto-parietal regions that show activity that is dependent on the type of switch and the degree of similarity or dissimilarity between tasks.
how does fight-or-flight work? What is the role of the HPA axis?
physiological changes as a result of emotional experience are considered a manifestation of the fight-or-flight response hypothalamus govern the level of activity of the autonomic nervous system which innervates body organs and sweat glands. during emotional stressors the ANS can activate the sympathetic nervous system that can increase heart rate, blood pressure, etc hypothalamus also controls hormonal system via pituitary gland which modulates the activity of other organs (HPA axis = brain's way of controlling the body's stress response through the loop that connects hypothalamus-pituitary gland-adrenal glands). pituitary releases hormones into the blood and these hormones affects organs such as the adrenal glands which produce hormones such as adrenaline and cortisol. pituitary --> ACTH Adrenal glands --> cortisol
How does the two-pathway hypothesis work? What are the conenctions?
quick (instinctive) pathway: thalamus-->amygdala pathway (thalamo-amygdaloid) (remember thalamus is an impt relay for sensory info to the cortex) this is a "first-alert" system. carries a crude preliminary sketch of some basic properties of the stimulus - just enough to ready or initiate a response. comprehensive context pathway: connects neocortex (sensory cortical areas) to amygdala (cortico-amygdaloid) allows the person to analyze the fear stimulus. delivers enough info to give rise to an affective reaction that takes into account the complexity and details of the situation (overall slower response).
the insula (insular cortex) general
representing bodily cues of emotion - the state of our body can be represented mentally. 3 subregions: 1. posterior portion --> projects to primary and secondary motor cortices and somatosensory cortex (primary sensory representations) b) Anterior portions --> anterior cingulate 2. dorsal anterior insula --> ACC involved in cognitive control (integrate these representations to our conscious awareness) 3. ventral anterior insula --> ACC involved in emotional processing when asked to detect their own heartbeat, the anterior insula was more active than compared to the control (an external stimuli such as sound). people who are more accurate at detecting their own heartbeats had a right anterior insula that was both bigger and more active compared to people with poor accuracy. (*shows it's important to encoding introceptive info) also important to registering disgust - in non-human primates, part of the insula serves as the primary gustatory (taste) area. same facial expression muscles active with taste aversion are activated when viewed photographs of disgusting images or when they experienced unfair treatment in a social game, and even when seeing another person expressing disgust. stimulation of insula in elicited sensations of unpleasant taste and nausea. damage to insula intereferes with experience of disgust and ability to recognize facial expressions of disgust in others.
Which hemisphere is more involved in generating/understanding facial expressions? What evidence supports this conclusion?
right-hem damage, esp. to the temporal and parietal regions of the brain affects facial recognition more than the left-hem. People with prosopagnosia can recognize others based on their emotional expressions but can't recognize faces whereas others without prosopagnosia cannot recognize expressions but can recognize faces (this double dissociation suggests two different mechanisms) recognizing expression and facial identity must share some visual processes, however there are some areas of localization ex. viewing emotional expressive faces activates the right FFA ex. fear and the amygdala - people with amygdala damage have trouble recognizing expressions, but particularly fearful expressions. basal ganglia damage --> can't make spontaneous facial expressions but can make voluntary facial expressions. Montreys and Borod - production of facial expressions are mostly right-hem dominated. people with unilateral (one side) brain damage are photographed or recorded while talking, watching emotinoal films,etc. The pictures recorded and rated by experts and found people with right hem damage are less expressive than left-hem damage. Sackeim - left-face composite (the wider one) are rated as more expressive Ross and Pulusu - spontaneous expressions tend to start on the left side of the face (which is controlled by the right), implying right-hem dominance even in the generation of expression non-human primates also exhibit more dramatic expressions on the left side of the face. all together, because of right-hem specialization for emotional expression and perception, emotion is most strongly expressed on the left side of a poser's face. and people are better at understanding emotional expressions seen int he left visual field or left side of space because of right-hem specialization. For two people directly facing each other in a communication context, the most expressive side of the face will be in the viewer's least sensitive half (they are on opposite sides). people have adapted to this phenomenon as people actually tend to turn their head more to the right to show more of the left side of the face. ex. portraits are more biased to showing more of the left portion of the face. when participants are asked to pose for a photograph in which they are encouraged to show their emotions, they are more likely to show the left cheek than if asked to pose for an neutral photo.
amgydala in general
role: important for early detection of emotional info, rapid response to that info, role in learning (emotional significance of info) 3 main subdivisions: 1. basolateral nuclei --> project to hippocampus and PFC, also regions involved in reward and punishment (allows amygdala to influence learning and memory esp. related to reward) 2. Central (cortical) nucleu and corticomedial nuclei --> project to hypothalamus, brain regions involved in autonomic and hormonal responses (allow emotional modulation of these responses) evidence using neuroimaging: - activity in the human amygdala increases in response to fearful compared to neural faces - activated in people with phobias when they are exposed to their feared object - amygdala responds to fearful images even when those images are presented outside of conscious awareness role in emotional learning: left amygdala esp. important for learning fear through verbal and/or visual learning rather than just direct experience of an aversive consequence. (ex. your parents telling you don't stick your finger in the socket it will shock you) Phelps experiment: participants shown different color squares and told that one specific color would be associated with shock (eventhough none occured). When participants viewed the specific color, the left amygdala was activated. damage to left not right disrupted verbal learning of fear. amygdala responds as strongly to positive emotional info as negative info. also different subsets of cells within amygdala are preferentially involved in aversive v. reward-based learning. arousal level of stimuli used to measure amygdala activity appears to be a modulating factor - negative stimuli tend to be rated as more arousing than positive (but this is just because there is different arousal level) amygdala activity increases as the intensity of the stimulus increases (+/- equally) some amygdala cells have valence-specific responses (only respond to +/-) there are others that respond to both +/- in a manner that is correlated with autonomic arousal. amygdala is NOT the only structure involved/important for emotional processing. amygdala interacts with several other brain regions and people with bilateral amygdala damage can still experience emotions.
Understand that people with frontal lobe damage have trouble planning and executing sequential behavior. What types of deficits might you expect on the self-ordering task when testing people with frontal lobe damage? How are these deficits related to working memory?
sequencing of behavior requires knowing what comes before and what comes after. neurons in the prefrontal cortex can distinguish between those tasks that have just been accomplished v. those that are about to be performed. disruptions to mechanisms that code for tasks or goals yet to be accomplished can lead to "errors of omission" in which a goal is not finished or accomplished. Disruptions to mechanisms that code for previously completed tasks can lead to perseveration. individuals with frontal lobe damage have difficulty remembering the sequence in which items appear. In one task, participants saw items such as line drawings one at a time and then shown two cards with two items. Patients with frontal lobe damage have no difficulty remembering which item they saw from the two, but they have trouble remembering the sequence in which the items were presented regardless if they are passively watching the sequence of events or if they control the order. self-ordering task = participants shown an array of items from the same category. a trial consisting of 6-12 sequential arrays with the same items rearranged. On each presentation, participants need to point to an item that they hadn't pointed to previously. (participant has to keep track of which items they chose previously (where was it located?)). deficits on this test in patients with frontal lobe damage, esp. in lateral damage seems to affect recency judgments = picking something that they haven't picked recently. neurologically-intact patients have greater activity in the lateral frontal lobe area when they make recency judgments. dorsolateral prefrontal regions also may be important because they support executive processes that act on info being maintained in working memory. in the self-ordered pointing task, executive processes are required to differentiate which items they have already selected and which remain in their working memory.
What kind of behavior might we expect to see in patients with frontal lobe damage on the Wisconsin? Why?
single-cell recordings from cells in the frontal lobe in monkey indicate there are neurons that allow coding for "rules", especially more abstract criteria for a category (house cat v. hairless sphinx cat). Neurons that abstractly code cats v. dog can (if task demands change) abstractly categorize sports cars v. sedans. These neurons can encode and categorize info in a rule-like manner. some frontal lobe patients have difficulty with abstraction and rule-like understanding. for the WCST, some people with frontal lobe damage exhibit only perseverative tendencies, others can't even figure out the criterion by which the cards should be sorted. Because they're not given concrete instructions (have to infer what the rule is based on if the card they placed down is said to be correct or incorrect) and they can't do this, they can't determine how to perform the task. In a modified WCST, they patient is given 6 cards to be sorted in 2 equal piles. Each card contains an animal's name and a triangle against a background of lines. There are 8 possible dimensions to sort them (animal lives on land v. water, triangle is black or white, position of animal's name is above / below triangle). Shows if the participant is able to sort or if their damage is too extensive because reveals difficulties in conceptualization.
With regards to the amygdala, what is Kluver-Bucy syndrome?
temporal lobe lesions in monkeys resulted in behavioral changes known as Kluver-Bucy syndrome: monkeys engaged in extreme behaviors such as loss of appropriate fear response, engaging in sexual activity with other species, eating objects such as feces Kluver-Bucy refer to these as "psychic blindness" = disconnection between the animals' ability to process the sensory properties of objects and their understanding of the affective properties of these same objects later studies found that only removing the amygdala produced many of these behaviors (not the entire temporal lobe) humans with amygdala damage lose ability to detect aversive emotional cues embedded in visual and auditory stimuli, difficulty identifying fearful facial expressions and fearful or angry sounds. also rate unfamiliar faces as more trustworthy than healthy controls would. They also are worse at discriminating between threatening and happy faces in a crowd.
What is interoception?
the ability to perceive and represent the internal state of the body (INTEROCEPTION) depends on insula
Imagine a patient has ventrolateral PFC damage. How might that affect their speech?
ventrolateral prefrontal regions may also aid in sequencing. Broca's area responds to sequential processing demands, regardless of whether info is linguistic or musical (syntax = meaning of the word order). patients with damage to Broca's show difficulty reproducing the sequence of visual items. This regions shows specific activatinon with healthy patients when sequencing demands were high because they were shown all info in the sequence at the same time.
Make sure you can describe the ERN and the Pe - Under what conditions do they occur? What is their temporal profile? How are they related?
we have particular set of brain mechanisms that helps to monitor our performance and detect errors. ERN = error-related negativity. It is an ERP component that occurs approximately 100 ms after an error has been made (it is a specific spike in activity). its amplitude INCREASES under conditions in which response ACCURACY is emphasized over speed. the larger the error the larger the amplitude of the ERN. It could be that the ERN is providing an undifferentiated signal that something has gone wrong (doesn't have to be task-specific, a general warning) Pe = error positivity, which frequently follows the ERN by about 200-300 ms. The source of this component is unclear but may be generated in the insula, a brain region associated with interoception (ability to sense the physiological condition of the body). this localization seems reasonable as we often have a physiological reaction to our mistake ("oops" stomach drop, heart rate increase)
Classical conditioning as it relates to a fear response? How do people with hippocampus and amygdala damage differ in response to fear conditioning? How do amygdala lesions affect fear conditioning?
when an aversive stimuli produces an emotional response, classical conditioning of a neutral stimulus with an aversive stimulus can eventually produce an emotional response / fear response to the neutral stimulus. damage to the amygdala disrupts fear conditioning (Bechara 1995) - a patient with bilateral amygdala damage and a patient with hippocampal damage were shown repeated pairings of a specific color slide with an unpleasant noise. after conditioning, neurologically intact people reacted to the slide by showing increased skin conductance (sweat). - patients with bilateral amygdala damage was able to remember the pairing explicitly but didn't show autonomic conditioned response. the patient with hippocampal damage however, showed normal autonomic conditioned response but were unable to remember that the blue slide led to the shock.
