Behavioral Neuroscience Exam 2

6 basic emotions

- 6 basic emotions: anger, fear, sadness, enjoyment, disgust, and surprise - Characteristics of these emotions: • Innate • Universal → seen across cultures • Short-lasting → maybe doesn't agree with this because what about depression and you could be sad for a very long period of time so this isn't short lasting - How many basic emotions really are there? Can we define basic emotions?

Parkinson's disease

- A disorder of the central nervous system that affects movement, often including tremors - Discovery of the drug MPTP (1982) led to the development of Parkinson's after heavily inducing this drug * MPTP is a synthetic opioid popular in the 80's - Facial expressions often seem "frozen" and even blinking is often absent - This discovery about MPTP in monkeys led to a breakthrough in PD research

Cerebellum

- A large structure of the hindbrain that controls fine motor skills - Different categories: 1. Neocerebellum: involved in motor planning 2. Spinocerebellum: motor execution 3.Vestibulocerebellum: Balance & eye movements: VOR keeps eyes on target - Cerebellum controls the same side of your body - Lesions lead to movement delays, incoordination, intention tremor, bad balance, and poor eye movements - Leads to non motor function damage too - Lesions to two of the cerebellum's three primary regions can lead to clumsy erratic movements and dysrmetria (overshooting or undershooting the target) - Damage to the: * Spinocerebellum results in trouble regulating performance * Neocerebellum results in trouble planning motor movement * Vestibullocerebellum results in trouble keeping the eyes on a visual object despite head or body movements and postural instability; may damage the eyeblink response

Selective Attention

- Ability to focus awareness on one stimulus, thought, or action while ignoring other irrelevant stimuli, thoughts, and actions * selective attention describes what we attend to and ignore within an specific level of arousal (high or low) - 2 categories of attention 1. Top-down processing: voluntary and uses personal knowledge to drive attention; goal-driven 2. Bottom-up processing: stimulus-driven; reflexive (loud bands, etc.); involuntary - Overt vs. covert attention * overt: the act of selectively attending to an item or location over others by moving the eyes to point in that direction * covert: mentally shifting one's focus without moving one's eyes (putting your attention onto something not actually looking at)

Overview of Motor Pathways

- All connections to the arms and legs originate in the spinal cord - The spinal signals are influenced by inputs from the brainstem and various cortical regions, whose activity in turn is modulated by the cerebellum and basal ganglia - Thus control is distributed across various levels of a control hierarchy - Sensory information from the muscles is transmitted back to the brainstem, cerebellum, and cortex (not shown) - The direct pathway between the basal ganglia and the motor cortex is excitatory for motor movement, whereas the overall effect of the indirect pathway through the internal globus pallidus (GPi) is inhibitory - A motor unit consists of the extrafusal fibers innervated by a single alpha motor neuron - Representing motor neurons in the spinal cord (and cranial nerve nuclei)

Visual Word-Form Area

- An area of the posterior temporal cortex that responds preferentially to words and other strings of letters - fMRI activation on the left regardless of which visual hemifield stimuli were presented in - In separate blocks of trials, words were presented in either the left visual field or right visual field * Independent of the side of stimulus presentation, words produced an increase in the BOLD response in the left fusiform gyrus (green circled region in top row), an area referred to as the visual word form * Dorsal to FFA

Importance of eye movements for visual attention

- Attention does more than modulate sensory processing - Intimately interrelated with eye movements - Is selective attention = control of voluntary eye movements?

Balint's Syndrome Anatomy

- Bilateral damage to posterior parietal & occipital cortex

Reflexive Attention

- Bottom-up, stimulus-driven process in which a sensory event captures our attention - Loud sound or movement in peripheral visual field - If salient, voluntary attention drawn to it

Associative Agnosia

- CAN perceive objects - CAN integrate objects into a whole scene - CANNOT recognize objects by name - Apperceptive and integrative agnosia patients cannot color the individual objects in a painting - Patient could not name visually presented objects but could color in the components of very complex drawings * clearly could perceive stimuli but unable to identify objects by name

Visual agnosia

- Characterized as the inability to recognize objects; impairment in the recognition of VISUALLY presented stimuli - Ex. the patient with visual agnosia is unable to recognize a fork by vision alone but immediately recognizes it when she picks it up

Helmholz and Covert Attention

- Covert fixations - shifts of attention over a scene without eye movements - were real - Fixate center and there is a brief flash of light --> people can perceive letters in area of covert attention but not elsewhere

Bilateral amygdala lesions > impaired implicit fear learning

- Did an CR experiment using shocks with patient SP who had bilateral brain damage and found that her explicit knowledge was intact, she expected the shock to occur, but did not have a conditioned response when just presented with a neutral stimulus and not a shock - SP showed no skin conductance response to conditioned stimuli - Hippocampal patients show opposite effect: CR but don't remember - SP could not be fear conditioned

How the brain works: "Now you see it, now you don't" study

- Different images are presented to a monkey, either an image of a starburst (pattern of some sort) or an image of a monkey face * trained to press right key when saw face and trained to press less key when saw starburst - Findings show that the cells in the temporal cortex respond vigorously to the monkey face but not to the starburst - In the rivalrous condition, the two stimuli are presented together, one to the left eye and one to the right eye, and the monkey must indicate their perception by pressing a lever - After about 1 second of seeing both stimuli, the animal perceives the starburst and the cell is silent during this period; while about 7 seconds, there is a large increase in cell activity which indicates that the monkey's perception has changed to see the monkey face image - Then, after about 2 seconds the monkey's perception flips back to the starburst and the cell's activity is reduced again - **Main finding was that the temporal cortex cell only fired when it perceived a face and not this pattern** Terms: - Binocular rivalry: different images simultaneously presented to each eye

Encoding and decoding neural activity

- Encoding refers to the problem of how stimulus features are represented in neural activity * image is processed by the sensory system and the scientist wants to predict the results BOLD activity in an fMRI - Decoding (mind reading) is the problem of predicting the stimulus that is being viewed when a particular brain state is observed - In fMRI decoding, the BOLD activity is used to predict the stimulus being observed by the participant * Encoding models are used to predict physiological responses, such as BOLD response to a stimuli * Decoding models are used in the reverse manner to predict the stimulus or mental state based on a physiological response such as BOLD activity on an fMRI

Fear potentiated startle: lab test of fear learning

- Fear-potentiated startle (FPS) is a reflexive physiological reaction to a presented stimulus, and is an indicator of the fear reaction in an organism - Did experiment with rats in a lab setting according to these steps, • Show light alone (CS): no response • Foot shock alone (US1): normal startle (UR) • Loud noise alone (US2): normal startle (UR) • Light and foot shock: normal startle (UR) • Light alone: normal startle (CR) • Light and sound but no foot shock: have an increased startled response → potentiated response (potentiated CR) * this is a potentiated response because the rat is startled by the loud noice and has associated the light with the foot shock

William James (1890)

- His thoughts on attention: " Focalization, concentration of consciousness are of its essence. "

Mind Reading

- How successful is fMRI at mind reading? - Show patients faces and buildings: during periods of face imagery, signals are elevated in the FFA, whereas during the imagery of buildings, signals are elevated in the PPA - Using just the data from the FFA and PPA of a single participant, it was possible to estimate with 85% accuracy whether the person was imagining a face or place - Could this be used in court? Ethical? Thoughts?

Other Brain Areas Involved in Recognition

- Image shown is the right-hemisphere cortical surface of an "inflated brain" in one individual identifying the extrastriate body area (EBA), fusiform body area (FBA), and face-sensitive regions - Regions responded selectively to bodies or faces versus tools - FFA: damage leads to an inability to recognize faces - Parahippocampal Place Area (PPA): damage leads to the inability to recognize a scene/landscape but can still recognize the items in a scene - Extrastriate Body Area (EBA): damage here could lead to an inability to recognize static and potentially moving images of body parts * many studies indicate that the EBA is involved in action perception as well (I.e. biological motion perception) - Fusiform Body Area (FBA): both the FBA and the EBA may be involved in integrating the color, motion, and shape of body parts

Pulvinar

- In humans, the posterior portion of the thalamus. It is heavily involved in visual processing and direction of attention. - Plays a very important role in attention - Lesions in this lead to hemisptatial neglect

Double dissociation between lesions of the superior colliculus and visual cortex

- In the orientation task, hamsters were trained to collect sunflower seeds that were held at various positions in space - In the discrimination task, hamsters were trained to run down one of two alleys toward a door that had either horizontal or vertical stripes - Lesions of the colliculus disrupted performance on the localization task - Lesions of the visual cortex selectively impaired performance on the discrimination task

Simultanagnosia

- Inability to perceive more than one object at a time - Inability to see multiple objects at one time; can't see whole - Could navigate her house of 25 years with eyes closed * with eyes open, using lamp to navigate, stumbled over dining room table

Balint's syndrome

- Is a rare neurological condition which causes a manifestation of visual and spatial difficulties due to the parietal lobe lesions - This condition can cause: 1. Simultanagnosia: patients can only see one item at a time * inability to perceive more than one object at once 2. Optic ataxia: objects mislocalized in space, cannot accurately reach for an object 3. Oculomotor apraxia: the inability to intentionally move your eyes towards an object - Task where doctor holds up a pocket comb and asks the patient what he sees: * the patient reports seeing the comb * then the doctor holds up a spoon and the pt. reports seeing a spoon * but when the doc holds up both the spoon and the comb at the same time, the patient says he can only see one object at a time - Difficulty making voluntary saccades - Test: "Are there circles of two different colors?" → can only see both colors when they are connected to the line so can only tell there are two colors when they are connected as one whole unit

The Limbic System

- Is the portion of the brain that deals with three key functions: emotions, memories and arousal - Essentially the limbic system deals with emotion * borders the corpus collosum - Emotion involves hypothalamus, anterior thalamus, cingulate gyrus & hippocampus and can also include limbic lobe, amygdala, orbitofrontal cortex, etc. - Not all Limbic structures (as defined by Papez & MacLean) are just emotion, e.g. hippocampus, and other structures are involved in emotion, e.g. insular cortex & some brainstem areas

Klüver-Bucy Syndrome

- Kluver and Bucy found that bilateral lesions to the anterior temporal lobe in monkeys resulted in sexual activity directed at inappropriate objects, lack of fear, lack of discernment in regard to food items, and an inclination to investigate objects with their mouths - Bilateral amygdala lesions in monkeys - Lack of fear and fear learning * Even if bitten, still approach snake - Bilateral damage to the amygdala in humans results in similar symptoms - People with Kluver-Bucy syndrome may also evidence visual agnosia, loss of normal fear and anger responses, loss of memory, distractibility, seizures, and dementia

Areas important for planning, control & execution of action

- Many cortical regions are involved in planning, control, and execution of movement Many cortical neurons innervate the cerebellum - The two major subcortical structures important for planning, control and executive functioning are the cerebellum and basal ganglia

Unilateral Spatial Neglect Anatomy

- Much worse with right hemisphere damage - Sometimes subcortical lesions - Regions of cortex known from neuropsychological studies to result in neglect when lesioned (look at picture)

Amygdala Essential for Fear Conditioning

- Neural activity changes during fear conditioning responses → could see this in the fear potentiated study done on rats - Mike Davis was an important Emory faculty that studied this - Amygdala integrates info from many sources - Both the CS and US sensory information enter the amygdala through cortical sensory inputs and thalamic inputs to the lateral nucleus - The convergence of this information in the lateral nucleus induces synaptic plasticity, such that after conditioning, the CS information flows through the lateral nucleus and intra-amygdalar connections to the central nucleus just as the US information does * ITC are intercalated cells, which connect the lateral and basal nuclei with the central nucleus

Attentional Control Networks

- Not a single area is in charge of attentional control - Complex network - Both goal-directed (top-down) and reflexive (bottom-up) - Modulates thoughts and actions as well as sensory processing

Emotion Affects Decision Making: OFC & Iowa Gambling Task

- OFC damage results in: poor decision making, not learning from one's mistakes, and not feeling regret o Game is comprised of 4 decks of cards: 2 cards represent small net gains and the other 2 represent big losses o Normal subjects learn to maximize their rewards - OFC normally responds to changes in rapids rewards and punishments so patients with OFC damage due poorly on this gambling task o Human fMRI: reward or punishment > ^ BF in diff parts of OFC o Medial OFC BF correlated with amount of regret

Neural Correlates of Anger

- Orbitofrontal and Anterior Cingulate Cortices * Activity in the right orbitofrontal cortex and anterior cingulate increased as the intensity of an angry facial expression increased - Activation correlated with increasingly angry expressions

Representational differences between the visual pathways

- Physiological responses of neurons in each lobe are distinct from each other Temporal Lobe Neurons: - Looked at single-cell recordings from a neuron in the inferior temporal cortex - Temporal lobe neurons are best suited for determining the identity of an object, meaning that the receptive fields for these neurons ALWAYS encompass the fovea and most of these neurons can be activated by a stimulus that falls within either the left or right visual field * typically, however, we tend to look directly at things we want to identify which takes greater advantage of our foveal vision - Cells within the visual areas of the temporal lobe have a very diverse pattern of selectivity * these cells are very excellent at detecting different features * in the posterior region, early in processing, the cells show a preference for relatively simple features such as edges * further along in processing, the posterior region shows a preference for much more complex features such as human body parts, apples, flowers, or snakes - always use the fovea and have diverse selectivity for faces, body, and objects Parietal Lobe Neurons: - Best for detecting the presence and location of a stimulus (spatial info) * known for the location of a stimulus and NOT the type of stimulus - Often extrafoveal - Neurons could be activated when a stimulus is restricted to a small region of space (I.e. the stimulus is just coming into your view, etc.) or when the stimulus is a large object that encompasses much of the hemifield (range of vision when one eye is looking straight ahead) - many parietal neurons are responsive to stimuli presented in the more eccentric parts (non-foveal vision) of the visual field * General: 40% of these neurons have receptive fields near the fovea, and the remaining cells have receptive fields that exclude the foveal region

Encoding of Information

- Processing/ creating a message so that it is in a form which can be easily sent (transmitted) - Sensory info is coming in and the brain is encoding this information - Study involved showing participants 360 words while they were undergoing fMRI scans → at a later time, showed participants 720 words and asked the participants if the words they saw were old or new (saw in scanner or didn't see words in scanner) • Hippocampus and cortex active during ENCODING of new memories (correctly remembered most items they had seen during the fMRI scans) • fMRI scans when initially exposed to the words • activity at encoding correlates with better recollection the words at testing - of red or green (see Figure 9.24) was correct. (a) Sagittal section through the right medial temporal lobe. Two regions in the medial temporal lobe that exhibited subsequent recollection effects were the posterior hippocampus and the posterior parahippocampal cortex - The hippocampus is ONLY active during correct retrieval / recollection - Increase in blood flow in hippocampus when they correctly remembered they had seen the word → this hippocampus different was during the retrieval process

Faces processed holistically

- Pt. CK (can't recognize circles, squares or figure of veggies) but can recognize veggies stacked to look like a face - Double dissociation with face blind patients - CK has integrative agnosia

Saccades

- Rapid voluntary movements of the eyes - We make a sequence of voluntary fixations, saccades, fixations as we view an image; we fixate most interesting parts

Morris Water Maze

- Rats learn to use visual cutes to find hidden platform in pool (and normally will place rat in different areas in the pool when doing this task) - Lesions to hippocampus caused impaired spatial memory • Cannot find platform using visual cues anymore (when put in different starting locations in pool) • But they CAN find the platform if placed in the same location each time → stimulus response learning - Evidence that the basal ganglia play an important role in stimulus response learning

Superior Colliculus

- Receives visual sensory - Receives rapid, unconscious responses to visual & auditory stimuli - Stimulation evokes eye & head movements - Express saccades - Engages cortical attention mechanisms

Insula

- Reciprocal connections with amygdala, medial PFC & ACC - Reciprocal connections with frontal, parietal & temporal assoc. cortex - Integrates info about internal body states & emotional state - Activated during risky decision making; more risky, more activation - Lesions: Reduced arousal & valence ratings to emotional pictures - Essential for experiencing & detecting disgust in others

Priming of visual cortex by spatial attention

- Same areas that WILL be activated by target are activated by attentional cue - Dorsal attentional network primes VI in preparation for visual stimulus - The same visual cortical activation is seen (attended vs. unattended) as in - Figure 7.20a, but collapsed over a group of six participants (from Hopfinger et al., 2000). (b) When these same regions of visual cortex were investigated before the targets actually appeared but after the cue was presented, a preparatory priming of these areas can be observed as increased activity. These regions of increased activity closely overlap with the regions that will later receive the target stimuli shown in (a), but the amplitude of the effects is smaller.

Face Recognition: Monkey Task

- Single neuron recording in the monkey's superior temporal sulcus * purpose was to identify face cells in the superior temporal sulcus of the macaque monkey - Showed monkeys different pictures (some of monkey faces, human faces, and random patterns) - Cells showed heighten activity in response to many of the facial stimuli - Either there was no change in activity when the animal looked at the objects, or, in some cases, the cells were actually inhibited relative to baseline * the firing-rate data are plotted as a change from baseline activity for that cell when no stimulus was presented - At least 2 face regions in monkeys: the superior temporal sulcus (present in humans too) and the inferotemporal gyrus (similar to the FFA in humans) * these regions were shown to respond to faces more than they responded to objects - 97% of neurons in the superior temporal sulcus show a strong preference for faces over objects

Cocktail Party Effect Cont.

- Someone mentions your name - You switch attention - Unattended info NOT completely filtered out - NOT just early selection - Unattended info is ATTENUATED (reduced but not completely filtered out)

Basal Ganglia

- Structures in the forebrain that help to control movement - The basal ganglia (BG) are a group of nuclei located in the basal (subpallial) part of the telencephalon and involved in control of motor behavior (including planning and execution of movement), as well as in cognitive functions such as motivation, attention, and learning

Triple dislocation of faces, bodies, and objects

- TMS target sites based on fMRI studies identifying regions in the right hemisphere sensitive to faces (OFA), objects (LO), and bodies (EBA) - In each panel, performance on two tasks was compared when TMS was applied in separate blocks to two of the stimulation sites, as well as in a control condition (no TMS) * The dependent variable in each graph is d', a measure of perceptual performance (high values = better performance) * Face performance was disrupted by TMS over OFA * Object perception was disrupted by TMS over LO * Body perception was disrupted by TMS over EBA - Faces: activity in the right occipital face area (rOFA) - Objects: activity in the right lateral occipital area (rLO) - Bodies: activity in right extrastriate body area (rEBA) - These discrimination tasks -- fMRIs and TMS -- showed triple dissociation in the recognition of these distinct categories Dilks Similar Study: - fMRI to locate Occipital Place Area (OPA), Occipital Face area (OFA) and Lateral Occipital Complex (LOC) * TMS of OPA impaired discrimination of scenes but not faces * TMS of OFA impaired discrimination of faces but not scenes * TMS of OPA impaired accuracy with scenes but not objects * TMS of LOC impaired accuracy of objects but not scenes

amygdala and brain connectivity

- The amygdala is heavily interconnected to many different parts of the brain → including the PFC, striatum, sensory neocortex, MTL memory system, cerebellum, and HPA axis - Influences many different regions of the brain

Subcortical areas important for action

- The basal ganglia proper include the caudate, putamen, and globus pallidus, three nuclei that surround the thalamus - Functionally, however, the subthalamic nuclei and substantia nigra also are considered part of the basal ganglia - The cerebellum sits below the posterior portion of the cerebral cortex - All cerebellar output originates in the deep cerebellar nuclei

Pride and Shame Emotions

- The graphs compare the mean levels of nonverbal behaviors spontaneously displayed in response to wins and losses by sighted athletes on the top and congenitally blind athletes on the bottom - These results show that athletes from 37 countries exhibit spontaneous pride and shame behavior that are the same

Anatomy of Attention

- The major regions of the brain involved in attention are portions of the frontal and parietal lobes and subcortical structures, including parts of the thalamus and the superior colliculi 1. Posterio-parietal lobe 2. Temporal-parietal junction 3. Pulvinar of thalamus 4. Superior colliculus 5. Ventral prefrontal 6. Superior prefrontal *** 7. FEF: Frontal eye fields *** 8. SEF: Supplementary eye fields

Activity of parietal neurons is enhanced with attention

- The monkey passively fixates while a lateral-field stimulus is presented, generating some action potentials from the neuron (passive fixation) - The monkey has the task of making a saccadic eye movement to the target and it appears the neurons showed increased firing to the stimulus - The animal must keep its eyes fixated straight ahead, but is required to reach to the target, the neuron increases firing rate to targets that are presented and covertly attended to - Shows neurons are spatially selective --> showing covert attention principles

Lateral Geniculate Nucleus (LGN)

- The part of the thalamus that receives information from the optic tract and sends it to visual areas in the occipital cortex - Functional MRI study of spatial attention effects in the lateral geniculate nucleus (LGN) - Before stimulus onset, an arrow cue at fixation instructed the participants which hemifield to attend - Next, a checkerboard stimuli presented bilaterally for 18 s - The task was to detect randomly occurring luminance changes in the flickering checks in the cued hemifield - Functional MRI activations (increased BOLD responses) were observed in the LGN and in multiple visual cortical areas - Increased activations were seen when the stimulus in the hemifield contralateral to the brain region being measured was attended - The effect was observed both in the LGN (top) and in multiple visual cortical areas (bottom) - Attention modulates sensory & perceptual processing - Supports early-selection models

Activity in V1 modulated by spatial attention

- There are attention effects in V1 simple cells - The stimulus sequence began with a fixation point and two color locations that would serve as saccade target - Then two flickering black-and-white patches appeared, one over the neuron's receptive field and the other in the opposite visual field - Before the onset of the stimuli, the monkey was instructed which of the two patches to attend - The monkey had been trained to covertly attend the indicated patch to detect a small color pixel that would signal where a subsequent saccade of the eyes was to be made (to the matching color) for a reward - The spatiotemporal receptive field of the neuron when unattended (attend opposite visual field patch) and when attended. Each of the eight panels corresponds to the same spatial location as that of the black-and-white stimulus over the neuron's receptive field - The excitatory (red) and inhibitory (blue) regions of the receptive field are evident; they are largest from 23.5 to 70 ms after stimulus onset (middle two panels) - Note that the amplitudes of the responses were larger when attended than when unattended - This difference can be seen in these receptive-field maps - Activity in V1 slightly modulated by spatial attention * V1 of the cerebral cortex is the first stage of cortical processing of visual information. Area V1 contains a complete map of the visual field covered by the eyes

Early versus late selection of information processing

- This conceptualization is concerned with the extent of processing that an input signal might attain before it can be selected or rejected by internal attentional mechanisms - Early-selection mechanisms of attention would influence the processing of sensory inputs before the completion of perceptual analyses - In contrast, late-selection mechanisms of attention would act only after the complete perceptual processing of the sensory inputs, at stages where the information had been recoded as a semantic or categorical representation (e.g., "chair")

Fusiform Face Area

- This region of the fusiform gyrus in humans is clearly preferential to faces → seen by fMRI evidence of signaling of neurons in this area showing the patients faces vs. other objects and record neuronal signaling - Image study using fMRI to isolate neural regions during face perception - Bilateral activation in the fusiform gyrus was observed with fMRI when participants viewed collages of faces and random patterns compared with collages of only random patterns - In another fMRI study, participants viewed alternating blocks of stimuli * in one scanning run, the stimuli alternated between faces and objects; in another run, they alternated between intact and scrambled up faces * the BOLD signal is much larger during intervals in which faces were presented

Why do we have a brain?

- To produce adaptable and complex movements, thoughts, etc.

Frontal Eye Field (FEF) stimulation impacts attention

- Use sub-threshold stimulation in frontal eye field * FEF has a saccade map --> can include scads with stimulation - Overlapped (saccade vector and receptive field overlapped) where covertly attending, would get higher spokes per second - Stimulating where you can cause saccadic eye movements effect attentional responses in V4 region - FEF stimulation that biases attention towards receptive field increases V4 activity

Valence and Arousal (intensity) as dimensions of emotion rather than categories

- Using valence and arousal as dimensions is another approach to characterize emotions, rather than using categories - Saying that all emotions have valence and arousal but the emotions vary by dimension - Arousal: intensity of an emotion - Valence: feeling of pleasantness or unpleasantness - Ex. a chair has a neutral valence and arousal but a snake might have negative valence and high arousal

Saccadic Expression

- We process visual info only during fixations - Avoids sensation of world moving

Amygdala, arousal and memory

- We remember emotional events MUCH better * First kiss, significant injury, car accident - Morris water maze * If rat is aroused (stressor), memory is enhanced * NOT if amygdala damaged or blocked - Amygdala modulates hippocampus * Enhances consolidation & retention - True in humans too * Arousal/emotion correlated with ^ retention * No ^ retention with lesions of amygdala - Ex. Patient SM with bilateral amygdala damaged showed no memory enhancement for the emotional-inducing part of a story - We also see an overactive amygdala in PTSD patients * In a study, the steep slope indicates amygdala was overly reactive to combat sounds in PTSD patients (with SPECT imaging)

How do we confirm that a patient with brain damage has agnosia?

- Wernicke's aphasia: difficulty understanding written and spoken language - Agnosia versus memory loss: * It is essential to rule out memory problems first when potentially diagnosing someone with an agnosic disorder * A patient with visual agnosia is unable to recognize a fork by vision alone but immediately recognizes it when she picks it up * The patient with a memory disorder is unable to recognize the fork even when he picks it up - MANY different varieties of agnosia (up to 26 types of agnosia)

Does attention affect sensory processing?

- Yes. - Did a study using event-related potentials in a dichotic listening task. - Hillyard and colleagues found that the amplitude of the N1 component was enhanced when attending to the stimulus compared to ignoring the stimulus. - Found event-related potentials in dichotic listening. - Supports these early-section models.

Integrative Agnosia

- a failure to integrate parts into wholes in visual perception * aka cannot integrate parts into a coherent whole - patients with integrative agnosia cannot see objects holistically - can copy down a whole image of shape but only go line by line and cannot copy them down shape by shape (copy down in weird segments) - problems naming objects Example Patient - Patient C.K. was asked to copy a figure shown - His overall performance was quite good; the two diamonds and the circle can be readily identified; however, as noted in the text, the numbers indicate the order he used to produce the segments

Patient SM

- bilateral damage to the amygdala - emotion afraid was rated less intense - did not understand fear--> actually seemed to seek out dangerous situations - often put herself in life-threatening situations - observed deficit in comprehending fear is also observed on a drawing production task (asked to draw representations of different emotions, I.e. disgust, etc.) - other emotions and emotional regulation appears normal - appears to have genetic damage to amygdala

Propagnosia

- is an impairment in the visual recognition of faces, or face blindness - 1/50 people; can be congenital (from birth) - May not be able to realize they are different than others - May not recognize self in own mirror - The Man Who Mistook His Wide for a Hat * Oliver Sacks had it * Mistook his wife's head for a hat * Greeted grandfather clock and not Dr. Sacks

Pure Alexia

- loss of the ability to read without loss of the ability to write - individuals who have pure alexia have severe reading problems while other language-related skills such as naming, oral repetition, auditory comprehension or writing are typically intact

Spatial Neglect

- objects in the contralateral visual field are ignored (meaning the side of the body opposite to that on which a particular structure or condition occurs) - may not bathe or shave contralateral side of body or face - cannot use contralateral limbs - do not recognize contralateral side of body - denies own limbs * once a man threw his leg out of bed because did not think it was his own and then he fell out of his own bed --> thought his own leg was a corpse - these people deny they have a problem - occurs most often in contralateral parietal stroke * tends to be more severe when right hemisphere is damaged - self-portraits by the late German artist Anton Raederscheidt, painted at different times following a severe right-hemisphere stroke, which left him with neglect to contralesional space - seen the world as their left side does not exist and do not use good arm to reach into that contralateral space - cannot overcome their neglect even at a cognitive level they realize that a clock is round (will still draw only half the clock) - there is also a gaze bias neglect: show an ipsilesional (same side as lesion, so right side) gaze bias when searching for a target letter in an array of letters - line bisection task: there is a piece of paper with horizontal lines on it and patients asked to draw a vertical line down the middle of each horizontal line * we see a bias in these tasks where the patients choose to bisect the horizontal lines to the right of the middle of each line (for patients with right hemisphere legions) * owing this result to the neglect for contralesional space and the contralesional side of individual objects - not just visual neglect, can apply to imagination and objects one imagines → however this is not a memory deficit - can identify large shapes but fail to mark component parts contralateral to lesion

Super Recognizers

- people with above average facial recognition abilities - 1-2% super-recognizers - sometimes used by Scotland Yard to identify faces

Acquired alexia

- reading problems that occur after the patient has a stroke or other head trauma

Optic Ataxia

- spatial disorientation in which the patient is unable to accurately reach for objects using visual guidance * aka a deficit in visual-manual guidance - patients with optic ataxia can recognize objects but cannot use visual information for guide action and reach for objects, etc. (video of guys trying to grab spoon and missing) - optic ataxia is associated with lesions or damage to the parietal cortex with is part of the dorsal stream of info (the "where")

Anatomy of object recognition

- specific regions of the brain are used for distinct types of object recognition - parahippocampal region and posterior parietal cortex process (NOT the superior parietal cortex) info about places and scenes * specifically spatial perception and localization of objects - multiple regions are involved in face recognition --> but primarily the fusiform gyrus and the superior temporal gyrus (hint: the face area is in the STS) * the fusiform gyrus = aka holds the fusiform face area (FFA) - other body parts are identified using regions within the lateral occipital and posterior inferior temporal cortex

Attention

- the ability to focus awareness on one stimulus, thought, or action while ignoring irrelevant stimuli, thoughts, or actions - attention influences how we process sensory inputs, store that info in memory, process it semantically, and act on it

Somatic marker hypothesis

- the idea that changes in the body, experienced as emotion, guide decision making - emotional info is needed to guide decision making

Parietal cortex activity: Attention or Intention or Both?

- the location of target is cued - instructed to either saccade or reach for target - delay; signal starts - spatial attention is the same in each

Perception

- the process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events - our view of the world depends on our vantage point - people perceive an object as a unified whole, not as an entity that is separated by its color, shape, or other details - our perception of things is flexible and robust at any angle or vantage point we are still able to perceive objects as a unified whole - memory and perception are highly linked/interwoven

Different Types of Agnosia

1. Apperceptive Agnosia: considered a problem in achieving object constancy - patient with apperceptive agnosia may recognize an object from a typical viewpoint, but performance deteriorates when asked to name an object that is seen from an unusual viewpoint or is occluded by shadows 2. Integrative: deficit that arises from the inability to integrate features into parts or parts of an object into a coherent whole 3. Associative: describes patients who are unable to access conceptual knowledge from visual input - perceptual abilities are relatively intact but fail to link representation to knowledge about what the object is used for, etc.

Muscles, Motor Neurons, and Spinal Cord

Alpha Motor Neurons - Innervate effectors - Final common pathway - Motor unit - Inputs: sensory affs., interneurons, descending - Come from CNS - Alpha motor neurons: Alpha motor neurons in the spinal cord communicate with muscle fibers by releasing the neurotransmitter acetylcholine, which influences muscle activity by directly causing muscle contractions - The activity of the alpha motor neurons determines the strength of contraction of a muscle Sensory afferents - PNS afferents are the axons of sensory neurons carrying sensory information from all over the body, into the spine - From skin, muscles, joints, and tendons Spinal Interneurons - Innervated by sensory afferents & inputs descending from supraspinal structures - Integrate sensory inputs with descending motor commands Antagonist pairs - Activation of bicep without activation of tricep and so forth General Important Terms - Effectors: arms, legs, hands, trunk, eyes, facial muscles, throat, tongue, etc. - Smooth muscle controls the internal organs - Striated muscle is responsible for the movement of your body through the environment - The fewer muscle fibers a single axon innervates, the more precise the movements - The synapse where a motor neuron's axon meets a muscle fiber is called the neuromuscular junction

Divided/Limited Voluntary Attention

Auditory selective attention in a noisy environment - The cocktail party effect of Cherry (1953), illustrating how, in the noisy, confusing environment of a cocktail party, people are able to focus attention on a single conversation, and, as the man in the middle right of the cartoon illustrates, to covertly shift attention to listen to a more interesting conversation than the one in which they continue to pretend to be engaged - Covert attention * this is the ability to follow one conversation in the presence of many other simultaneous conversations - Limited capacity for attention * divided attention is more challenging to maintain when tasks are difficult, require conscious attention, and are similar to other tasks * divided attention is easier to maintain when you engage in a well-practiced task that requires little conscious awareness, is not difficult, and is not similar to other tasks Invisible Gorilla - Focus on 1 thing at a time - Process high-priority inputs

Dorsal Attention Network

Coritical Regions Involved in Attentional Control - Diagrammatic representation of cortical activity seen during attentional control - Dorsal attention network involved: intraparietal sulcus (IPS), the superior parietal lobule (SPL), the frontal eye fields (FEF, PCUN = precuneus, and SEF = Supplementary Eye Fields - Top down, endogenous attentional control --> goal-directed, voluntary control of attention - Covert orienting of attention - Target appears 8 s later * activation before the target appears but ONLY with covert attention, not with passive viewing

Attention affects sensory processing

Dichotic listening study setup - Different auditory information (different stories) are presented to each ear of a participant - The participant is asked to "shadow" (Immediately repeat) the auditory stimuli from one ear's input (e.g., shadow the left-ear story and ignore the right-ear input) * shadowing: listening to two different messages and repeating back only one of the messages as soon as possible after you hear it - Dichotic listening - Focused on left ear - Immediately repeat - Found that they could not report speech in right ear - Found that we had a limited capacity of attention and listening skills

Memory consolidation and ECT

Effects of ECT on memory performance: - ECT is a transitory electrical shock, applied to the scalp, that results in an electrical convulsion. - ECT is used to treat depression. - After electroconvulsive therapy, patients show a temporally graded retrograde memory loss. - This tells us that memory apparently changes for a long time after initial learning. - Some material is forgotten, and the material that remains becomes more resistant to disruption. - Treatment for people with severe depression and is a pretty effective treatment for people with TRD → effects occur immediately as well so good treatment for people who are severely depressed and suicidal. - Memory consolidation: • Initial rapid phase mediated by hippocampus • Slower permanent phase involves neocortex • Memory loss is a known problem of ECT: could get temporal lop lesions which could lead to severe retrograde amnesia - Memories stored in cortex: Cortical stimulation - Temporal pole lesions > severe retrograde amnesia

Amygdala and social stimuli

Fearful faces - Briefly flashed happy or fearful face (33ms) - Then showed neutral face (167ms) - Subjects only perceived neutral face - Amygdala: Higher BOLD signal with fearful than happy faces Trustworthiness - Patients with amygdala damage cannot identify untrustworthy faces

HPA Axis

Hypothalamic-Pituitary-Adrenal Axis - Interaction between the nervous and endocrine systems to produce the body's response to stress - Elevated levels of one of these hormones may lead to depression - Autonomic NS & HPA axis mediate physiological responses to emotional stimuli, e.g. fight or flight

Apperceptive Agnosia

Overview - a failure to understand the meaning of objects due to a deficit at the level of object perception - early perceptual deficits --> can see stimuli just do not know what it is - cannot distinguish between shapes - confused by shadows and cannot copy down images - these patients can recognize objects when full visual info is given but ability diminishes when perceptual input is limited (I.e. shadows or an image that doesn't include the salient features of the stimulus) Tests to ID Apperceptive Agnosia: 1. Unusual-views test: subjects must judge whether two images seen from different vantage points show the same object * did this with the front of a cat and then showed the back of the cat --> patients with right-hemisphere lesions, especially in the posterior area, performed much worse than patients with left-hemisphere lesions 2. Shadows test: participants must identify the object(s) when seen under normal or shadowed illumination * patients with right-hemisphere lesions, especially in the posterior area, performed much worse than did control participants (not shown) or patients with left-hemisphere lesions

Study in monkeys involving the dorsal and ventral pathways of the brain

Overview of Studies: - In 1982, Ungerleider and Mishkin did a study that investigated object recognition and landmark recognition but did this by first making lesions in the monkeys' brains - In the first task (the object recognition task), monkeys had to study an object and then at the test phase, they had to chance to choose the non-test object in order to receive a reward - In the landmark task, monkeys had to learn about landmarks and then they were asked to choose the foodwell that was closest to a tall cylinder (aka the landmark) in order to receive a reward Results Found: - Found that temporal lesions impaired the object task, so impaired object recognition and thus involves the ventral stream - Found that parietal lesions resulted in impaired performance on the landmark task so aka poor spatial perception and thus must involve the dorsal stream - These focal lesions resulted in very selective deficits and provided evidence for double dissociation (is when two related mental processes are shown to function independently of each other) - After this study, it was proposed that we view the mammalian visual system as organized in two separate, multi synaptic pathways --> one dorsal and one ventral

Effect of microstimulation of a face-selective region within inferior temporal cortex of a macaque monkey

Overview of Study: - Monkeys presented with different images - Random dots were added over the images to make it hard to differentiate between a flower (-100% image) and a face (+100% image) * 0% stimulus was only random dots - Image presented for 50 ms Findings: - The monkey was very accurate whenever the image contained at least 50% of either the flower or face stimuli so testing was limited to stimuli between −50% and +50% - Showed percentage of trials in which the monkey made an eye movement to indicate that the stimulus contained a face and not a flower * "Face" responses were more likely to occur on experimental trials compared to control trials SHOWS THAT: - Single cell recording and fMRI studies are correlative - Microstimulation more likely to elicit more face responses

Action vs. Identification Tasks (Involves Patient DF)

Patient DF - Patient DF has bilateral damage to the ventral pathway (responsible for object recognition, the "what") due to carbon monoxide poisoning * this lead her to have a severe object recognition disorder - Structural MRI scans showed that D.F. has widespread cortical atrophy with concentrated bilateral lesions in the ventral stream that encompass the lateral occipital cortex (LOC) Explicit Matching vs. Action Task - Two tasks were asked: 1. The explicit matching task when asked to match the orientation of a card so that it could fit in a slot provided * performed very poorly in this task * pt. has visual agnosia which hampered her ability to use the object's orientation information to complete this task --> couldn't access this information ** has damage to ventral pathway so couldn't access info about the card 2. Action task when actually asked to put the card into the slot provided * pt. could do this task without hesitation * could do this through the dorsal system by using spatial information which guided her interaction with putting the card in the slot - essentially pt. couldn't recognize orientation of card and had severe object naming deficits as well --> this patient had visual agnosia (deficit in visual recognition)

Social Group Evaluation Using the IAT

Phelps et al. (2000) Racist ideology - fMRI study - Famous or unfamiliar black or white faces were shown to participants - In whites participants, amygdala activation with unfamiliar black faces correlated with indirect measures of racist ideology (the IAT)

Amygdala & explicit fear learning

Responses to Instructed Fear - While performing a task in the instructed fear protocol, participants showed an arousal response (measured by skin conductance response) consistent with fear to the blue square, which they were told might be linked to a shock - The presentation of the blue square also led to amygdala activation - There is a correlation between the strength of the skin conductance response indicating arousal and the activation of the amygdala - When CS is presented, participants show increased amygdala activation - The amygdala is sometimes critical for the indirect expression of a fear response when the emotional learning occurs explicitly

Spatial Attention Modulates V4 Activity

Spatial attention modulates activity of V4 neurons - The areas circled by dashed lines indicate the attended locations for each trial - A red bar is an effective sensory stimulus, and a green bar is an ineffective sensory stimulus for this neuron - The neuronal firing rates are shown to the right of each monkey head. The first burst of activity is to the cue, and the second burst in each image is to the target array (a) When the animal attended to the red bar, the V4 neuron gave a good response (b) When the animal attended to the green bar, a poor response was generated - 2 stimuli: Match-to-sample task - Neurons respond to red bar

Covert spatial attention affects visual processing

Stimulus display used to reveal physiological effects of sustained, spatial selective attention - The participant fixates the eyes on the central crosshairs while stimuli are flashed to the left and right fields - In one case, the participant is instructed to covertly attend to the left stimuli, and ignore those on the right - In another case, the participant is instructed to ignore the left stimuli and attend to the right stimuli - Then the responses to the same physical stimuli, such as the white rectangle being flashed to left visual hemifield in the figure, are compared when they are attended and ignored - Sensory ERPs recorded from a single right occipital scalp electrode in response to the left field stimulus * The waveform shows a series of characteristic positive and negative voltage deflections over time, called ERP components --> notice that the positive voltage is plotted downward - Attended stimuli elicit ERPs with greater amplitude than do unattended stimuli - Supports early-selection models * filter rejected the unattended message at an early stage of processing - Suggests spatial attention modulates neural activity at VI

The Five Pathways to the Spinal Cord

The brain innervates the spinal cord via the pyramidal and extrapyramidal tracts - The pyramidal (corticospinal) tract originates in the cortex and terminates in the spinal cord * Almost all of these fibers cross over to the contralateral side at the pyramids - The extrapyramidal tracts originate in various subcortical nuclei and terminate in both contralateral and ipsilateral regions of the spinal cord - Pyramids: bilateral bumps on the ventral medulla (tight bundles of corticospinal tract) - One major difference between the pyramidal and the extrapyramidal motor tracts is their point of origin * The pyramidal tracts carry messages from cortical structures to the spinal cord, whereas the extrapyramidal tracts carry messages from subcortical structures to the spinal cord - Lesions to the pyramidal motor tract produce difficulty in moving effectors on the contralateral side

Behavioral Studies of Spatial Attention

The spatial cuing paradigm popularized by Michael Posner and colleagues at the University of Oregon - A participant sits in front of a computer screen, fixates on the central cross, and is told never to deviate eye fixation from the cross - An arrow cue indicates which visual hemifield the participant should covertly attend to - The cue is then followed by a target (the white box) in either the correctly cued (a) or the incorrectly cued (b) location - On other trials (c), the cue (e.g., double-headed arrow) tells the participant that it is equally likely that the target will appear in the right or left location - FOUND that reaction times for expected behavior of box to be sig faster than those unexpected and neutral locations of the box - Covert attention improves performance, e.g. button press - Leads to faster sensory and perceptual processing -According to Posner, three things must happen in order for appropriate attending to occur: 1. Subjects must disengage from wherever they are currently attending 2. They must move their attention to the new location 3. They must engage their attention with the new location

Dorsal versus Ventral Streams

The two primary object recognition pathways: 1. The Dorsal Pathway (aka occipitoparietal pathway) - this is responsible for the "where" an object is --> the dorsal stream is specialized for spacial perception - is responsible for spatial relation to the locations of other objects as well - vision for action - involves the postero-parietal cortex - also known as the "where" or "how" pathway 2. The Ventral Pathway (aka occipitotemporal pathway) - specialized for object perception and recognition --> determining "what" we are looking at - involves the inferior temporal cortex **Important Point: - Neurons in the parietal lobe have large, nonselective receptive fields that include cells representing the fovea and the periphery - Neurons in the temporal lobe have large receptive fields that are much more selective and always represent foveal information

Localizationist view of emotions

This is the idea that specific regions of the brain are hypothesized to be associated with specific emotions. o Overwhelming amount of evidence that amygdala is involved in fear but it is proven to be involved in other things as well o Insula: evidence that it is involved in disgust o Anterior cingulate gyrus: involved in the process of sadness o Orbitofrontal cortex: said to be involved in anger → Dr. Crutcher has problems with this view because only small part of the cortex is actually activated by anger so big simplification

Disorders of Attention Overview

Unilateral Spacial Neglect: worse with right side lesion - Poor search in the neglected field - Failure to orient self or objects correctly (failure to account for ignored side of space) - Inaccurate determination of midline - Hypomotility (deficit in movement on left side) on left - Unaware of disability Balint's Syndrome: bilateral parieto-occipital lesions - Paralysis of gaze (difficulty with peripheral field) - Optic ataxia, in which the patient cannot use visual information to accurately coordinate actions * poor visual guidance of reaching movements - Difficulty attending to the peripheral fields when actively attending to the environment - Oculomotor apraxia: difficulty making voluntary saccades; sometimes congenital) - Simultanagnosia

Comprehension in patient thought to be in vegetative state

While in the MRI scanner, the patient and control participants were given various imagery instructions (tennis imagery and spatial negative imagery, boy walking in a space) - The patient exhibits similar BOLD activity as observed in the controls, with increased activation in the supplementary motor area (SMA) when told to imagine playing tennis and increased activation in parahippocampal place area (PPA), posteroparietal cortex (PPC), and lateral premotor cortex (PMC) activity when told to imagine walking around a house

Taxi Drivers and Hippocampus Study

o In London the taxi drivers who had to memorize the roads and didn't have GPS had larger posterior hippocampi o Could be explained by adult neurogenesis and found that adult neurogenesis can occur in the hippocampus

What is an emotion?

o Valenced (unpleasant or pleasant) response to external stimuli or a memory o Can be trigged by external event or an internal memory o 3 components /characteristics: (these are highly accepted in the literature) • Physiological reactions (I.e. fight or flight response) • A behavioral response • "A feeling"

Critical role of subcallosal cingulate in treatment-resistant depression

o When someone is in a depressed mood, there is an increased blood flow to SCC25 region → decreased this with successful depression treatments o Sustained increased blood flow in the SCC is shown to be active in TRD patients o Could there be a dysregulated Cg25 connectivity here too?

Place Cells and the Noble Prize

• John O'Keefe: won the Nobel Prize in Physiology/Medicine in 2014 for the discovery of place cells o Whenever rat was in certain place in environment, a certain neuron will fire when rat is in specific place in environment but won't fire when the rat was in other locations → different neurons "fire" when we are at different locations in space • I.e. experiment with rats running around and recording brain activation imaging o First evidence that hippocampus is involved in spatial learning and memory

Stretch Reflex

• Muscle spindles sense muscles length and stretch of muscle • Monosynaptic, counteracts unexpected stretch → counteracting unexpected stretch by making leg contract - When the doctor raps your knee, the quadriceps is stretched * This stretch triggers receptors in the muscle spindle to fire * The sensory signal is transmitted through the dorsal root of the spinal cord and directly activates an alpha motor neuron to contract the quadriceps * In this manner, the stretch reflex helps maintain the stability of the limb following an unexpected perturbation - An important function of the monosynaptic stretch reflex is to help maintain posture - A sudden stretch of a muscle excites a feedback system that opposes the stretch - This message starts in the muscle spindle (which is the stretch receptor)