Cognitive Psychology PDF

deck_16852172 Question Answer Selective attention...

deck_16852172 Question Answer Selective attention The ability to prioritize and attend to some things while ignoring others Overt vs. covert Overt: moving eyes to the location/object/feature Same or di erent neurons? Covert: attention without moving the eyes Same parietal neuron res for both Voluntary vs. re exive attention Voluntary: choosing what to attend to based on current goals (top-down), ventral parietal Bottom-up vs. top-down Re exive: automatically orienting to new information (bottom-up), dorsal parietal Ventral vs. dorsal parietal Posner Cuing Task (measures attention to space) Arrows indicate which side the target will appear on Valid, invalid, and neutral Valid: arrow is correct Invalid: arrow is wrong Neutral: either side is equally likely Valid vs. invalid condition and voluntary vs. involuntary attention Valid condition uses voluntary attention, and response time is faster Invalid condition uses re exive attention, response time is slower Re exive attention and response to features, eg. gray letter, horizontal number Re exive attention responds to pop-out features When is search slowest? Response time is much slowest for voluntary, controlled search What lobe of the brain is responsible for control of attention? Parietal lobe (active primarily for switching attention) What lobes are responsible for voluntary vs. re exive attention? Voluntary: Superior Parietal Lobe/IPs and Frontal Eye Field (FEF) SPL, FEF, TPJ, VFC Re exive: Temporal Parietal Junction (TPJ), Ventral Frontal Cortex (VFC) fMRI activity in TPJ and IPS during Posner Cuing Task TPJ is more active for invalid trials and for target, NOT cue (arrow) IPs (voluntary) is active for valid and invalid, and for cue (arrow) Attention and sensory processing Attention allows us to select what stimuli we are paying attention to by "priming" areas of the brain to attend to speci c objects, features, or spaces ERP study and Posner Cuing Task Enhanced responses when target is on the attended side Stroop Task and attention to color Greater activity in the color area, less in word area vs. control task Parietal lobes and sensory areas Suggests that parietal lobes direct (control) sensory/perception regions to be enhanced/inhibited Disorders of spatial attention Unilateral neglect: de cit in attending to information on contralesional side of space 3 Extinction: inability to perceive stimuli on contralesional side when there are stimuli on healthy side Unilateral, extinction, Balint's Balit's syndrome: only can see one object at a time Unilateral neglect and extinction Re exive attention de cits Re exive or voluntary Often in the right parietal lobe, usually IPC (Inferior Parietal Cortex) What part of the brain? Examples of unilateral neglect Visual search: patients fail to search the left side of space for the target Posner cuing task Posner: neglect patients are slower to detect leftwards target than right Visual search task Stronger alpha waves for right hemisphere = greater suppression Alpha waves Memory and unilateral neglect When asked to describe village, patient could describe neglected eld information if asked to face the other direction, towards intact side Village imagery Memory is still intact Unilateral neglect and environmental vs object attention Neglect is object AND spatial Horizontal line drawing Patient will neglect left side of the space and the left side of the object Extinction Attention is biased away from contralesional side (towards intact eld) when competing stimuli are present What happens when competing stimuli are present? Attentional disorders are domain general Span all the senses, including touch Object knowledge and extinction Patients are less likely to ignore left (impaired) object if the two objects are di erent Action knowledge and extinction Action knowledge increased likelihood that ignored eld information will be reported Object orientation Objects at correction orientation are more likely to be reported Is unattended information represented in the brain Yes! Recognizing object, action, and feature information means that we are somehow processing those details even if we aren't consciously aware Balint's syndrome Severe loss of spatial representation-di culty binding details Impaired dorsal pathway (which lobes?) A) Optic ataxia: impaired vision guided reaching 3 features: B) Ocular apraxia: inability to voluntarily control gaze Optic ataxia, ocular apraxia, simultanagnosia C) Simultanagnosia: inability to recognize more than one object at once Posterior parietal/lateral occipital lesions Illusory conjunctions Combining features of two separate objects into one object Attention is required to correctly bind features together What unattended information is represented in the brain? 1. Feature information (colors, shapes) 2. Object information (eg. a key and a fork, two di erent objects) 3. Action information (eg. object orientation) 4. Memory remains intact Hierarchy of action control 1. Conceptual level "do you want to dance?" 2. Response system level- selecting a response 3. Motor implementation Motor pathway Premotor and supplementary systems->primary motor cortex->brainstem->spinal cord Corticospinal/pyramidal tract Responsible for voluntary control Longest neurons in the brain Primary motor cortex->midbrain->medulla->spinal cord 90% crossed Synapse at alpha motor neurons (control muscle contraction) Electromyography Measures electrical activity caused by alpha motor neurons ring Agonist/antagonist muscles Agonist contracts while antagonist relaxes to allow movement Ex. biceps and triceps Re exive movement Sensory neuron (dorsal root)->motor neuron (ventral root) in spinal cord No motor cortex processing Dorsal=to CNS, vental=away from CNS Primary motor cortex (M1) Responsible for the execution of movement How is it organized? Organized by body part How are neurons specialized? Neurons are specialized for direction of movement Population vector The sum of the preferred directions of a population of neurons Movement is a function of summed activity of all neurons Disorders of movement Hemiplegia: loss of voluntary movement in contralateral limbs Hemiplegia Hemiporesis: weakness/impaired control of contralateral limbs Hemiporesis Motor planning action plans Not tied to a speci c body part Ex. you can write with multiple body parts TMS of SMA-planning vs M1 (primary motor cortex)-execution SMA (supplementary motor area): Timing of errors, complex vs. simple tasks Delay in errors, only for complex sequences-partial action plan already in m1 ex. forgetting which step M1: Immediate errors, in complex and simple tasks ex. hand is stuck Parietal lobe vs. M1 activation during learned task for di erent body parts Parietal lobe is activated in the same area for both arm and hand-encodes action plan regardless of body part M1 had di erent regions activated for arm vs. hand Apraxia Loss of ability to generate coordinated purposeful actions NOT due to loss of muscle control Di culty with action planning Particularly with miming movements ex. whistling, blowing out a match Video games and cognitive skill improved ability to focus on visual details heightened sensitivity to visual contrast mentally rotate objects more accurately quicker reaction times to sudden events better decision making under pressure Brain regions with activity changes due to video games dorsolateral prefrontal cortex: helps sustain attention Dorsolateral prefrontal, parietal, and cingulate cortex parietal cortex: switches focus among di erent targets cingulate cortex: monitoring one's own behavior Action vs. nonaction video games Action video games that emphasize attention, exibility, and speed show cognitive gains, where nonaction games do not Populations not bene tted by traditional action games ADHD, older players, lazy-eye patients Cumulative cultural evolution (CCE) the process by which incremental accumulations of changes to a cultural trait lead to functional improvement in performance Requires social learning Two parts of chimpanzee experiment (1) whether naive chimpanzees who were exposed to all relevant materials could master the required skill by themselves within a prolonged period (2) whether naive chimpanzees could acquire the skill by observing a pro cient (trained) conspeci c model Results of chimpanzee study 1: not a single chimpanzee out of the 66 residents was successful in operating the apparatus through the drawer mechanism once 2: 14 naive chimpanzees who at some point during the experimental sessions mastered the skill (watching trained chimp) Results of chimpanzees observing task being solved the more times chimpanzees observed the task being solved, the faster they were to start interacting with it, and the faster they were to solve the task once they had started interacting with it Mirror neurons Neurons in premotor cortex (frontal) that re for both observing and performing Monkeys, dogs, and human motor neurons for familiar action vs "speaking" action Familiar (biting): activation in mirror circuit Speaking (silent speech, barking, lip smacking): activation only in humans Fine motor coordination brain regions Basal ganglia and cerebellum What is the cerebellum involved in? Motor timing, feedback, execution, planning, balance, and eye movements What is the basal ganglia involved in? Initiation, switching between motor tasks Not just motor Also cognition Agonist/antagonist muscles in cerebellar lesions Poorly timed=poor coordination Rabbit and air pu feedback and cerebellar lesions Rabbits with cerebellar lesions could not learn from stimulus to close their eyes in time for the pu Prism glasses and cerebellar lesions Cerebellar patients could not correct for distorted vision from glasses-they never hit the target Typical patients adapted to distorted vision, and had to adjust back after glasses were removed 1  ffi fl fl fl fl fl fl fl ff ff fl ff fi fi fi fi fi fl ffi ff fi fl ff fl fi ff fi fi fi fi ff ff fi fi  Ataxia Impaired coordination despite knowledge of correct action Cerebellar lesions 5 nuclei of basal ganglia Caudate and putamen (striatum) Globus pallidus Sub-thalamic nucleus Substantia nigra Two pathways of the basal ganglia Direct: excitatory (inhibits inhibitory neurons) Indirect: inhibitory Basal ganglia as a dam Basal ganglia is inhibitory by default The most active motor response overcomes the dam Two key aspects of Parkinsons Akinesia: problems in shifting motor state eg. from one key pattern to another Akinesia and bradyphrenia Bradyphrenia: problems in shi ting cognitive state, eg. from naming color to naming shape Parkinsons and loss of dopaminergic projections from substantia nigra to striatum Reduced excitation of cortex More inhibition of thalamus Hippocampus and memory during sleep The hippocampus replays memories during REM sleep David Marr Key to memory consolidation Targeted memory reactivation (TMR) researchers played unique sounds while people memorized the locations of 50 objects on a computer screen eg. meow and cat Roles of motor cortex, secondary/association, cerebellum, and basal ganglia in movement/action Motor cortex: motor execution Secondary/association: motor planning, action perception Cerebellum: motor coordination, feedback learning Basal ganglia: state changes Action plans during memory/delay period Action plans for both possible tasks are active during memory/delay period, at cue, one is enhanced while other is suppressed Brain-machine interface Computer decodes patterns of neuronal ring to move a robotic limb or the person's own limb based on intention of movement Types of long term memory Explicit/declarative: episodic (events) and semantic (facts, world knowledge) 2 main branches, 2 sub branches Implicit/non-declarative (performance): skills, conditioned responses, perceptual priming, sensitization, habituation Disorders of declarative/explicit memory Anterograde amnesia: Anterograde and retrograde amnesia problem with "learning", forming new memories Loss of memory for events after disturbance Retrograde amnesia: problem with "memory", recalling Loss of memory for events before disturbance Clive Wearing Bilateral hippocampal lesions, and some prefrontal damage What kind of amnesia did he have? Anterograde amnesia What kind of damage did he have? What brain region is associated with anterograde amnesia? Medial temporal lobe (hippocampus, amygdala, mammillary bodies, thalamus) Korsako 's Disease Due to a lack of thiamine, often caused by alcoholism What brain region is a ected? Leads to degradation of mammillary bodies->anterograde amnesia What do patients display? Patients often confabulate, and are unaware that they have memory issues Is alzheimers disease a retrieval problem or a storage problem? When neurons associated with the fear response were tagged and light-activated, the long-term memory was restored Mice with fear reactions AD is a retrieval problem, not a storage problem Amnesiacs and procedural memory Amnesiac patients show intact procedural learning on performance tasks ex. HM improved on mirror gure drawing ex. patients learned to weave Threshold reading task Hippocampal patients had normal priming but impaired recall (if word was in study set) Double dissociation between declarative and non-declarative memory Occipital patients had impaired priming but normal recall (if word was in study set) Hippocampal vs. occipital patients Weather task double dissociation Parkinson's patients show intact declarative memory (recalling details) but impaired non-declarative memory (learning patterns) Parkinson's vs. hippocampal patients Hippocampal patients show the opposite Morris Water Maze Hippocampal lesion rats could not learn where the platform was, and could not locate the platform in cloudy water Cortical lesion vs. hippocampal lesion rats London taxi drivers Taxi drivers show increased volume, and increase is linked to time on the job Posterior hippocampal volume Hippocampus and parietal lobe and spatial memory Hippocampus creates a spatial map, parietal lobe reads map Hippocampus during sleep Neurons re quick replays of learning episodes-encode memories Hippocampal activity during recalled vs. forgotten tasks Hippocampal activity is greater during encoding for correctly recalled words, scenes, etc., especially for events Ex. while watching scene, or while making size/animacy judgements Long term potentiation (LTP) and long term depression (LTD) and consolidation LTP strengthens synaptic connections, LTD weakens Hippocampus consolidates multiple representations of an event into one memory Hebbian learning Neurons that re together become wired together 3 rules 1. Cooperativity: there must be more than 1 input active 2. Associative: weak and strong must co-occur 3. Speci city: only active neurons potentiate Ataxia vs. apraxia Ataxia: loss of muscle control/coordination, a ects all actions Apraxia: inability to carry out familiar movements (eg. whistling, blowing). Spontaneous movements possible Relational memory the ability to remember the connections between people, places, objects, and events Implicit Hippocampus lesions: intact shape discrimination, but no relational memory How does it relate to hippocampal patients? 2  fi ff fi fi ff fi fi fi ff