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138 Cards in this Set
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attempt to infer function of region by taking people with lesions to that region and seeing the impairment
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classical neuropsychology
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Using patterns of impairment to infer cognition, regardless of location
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cognitive neuropsychology
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Combination of different patients performance to get averages
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Group studies (used with classical neuropsych)
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Taking the lesion info from a single patient
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Single Case studies
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Non-invasive magnetic stimulation of the brain t produce temporary virtual lesions
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TMS (Online/offline, slow/rapid)
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neurosurgery, stroke, traumatic head injury, tumor, viral infection, neurodegenerative disorder
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Ways to get damage:
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When patient impaired on particular task and spared on another
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Dissociation (classical and strong)
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When patient perform entirely normal on one task and impaired on another
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Classical Dissociation
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When performance impaired on both task, but worse on one
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Strong Dissociation
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two tasks with same cognitive resource but one uses it more, that area will suffer greater damage with lesion
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Task Resource Artefact
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performing one task sub-par to another, not due to faulty task
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Task Demand Artefact
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two single dissociations with complementary profile of abilities (to dispute TRA)
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Double Dissociation
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1. Fractionation assumpt:damage to brain can cause selective cog lesions.
2. Transparency: lesions affect more than 1 component of cog system and not create whole new system. 3. Universality assumpt:all cognitive systems basically the same **Problems: not necessarily true (2-say that when remove part of cog system, not rearrange/use different system) |
Caramazza's 3 assumptions of neuropsych data w/theorizing
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Cluster of different symptoms that are thought to be related in some way.
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Syndrome
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syndrome: possess cluster of different symptoms
cognitive syndrome: possess specific symptom anatomical lesion: if have lesion in particular anatomical region. W/specific, testable |
Groupings to associate lesion site with deficit
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Brain lesions impact brain regions that still intact
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Diaschisis
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imaging data say region essential for task, lesion say no: activation b/c area inhibited, unnecessary strategy adapt by pps, area IS essentia in task but lesion data not have enough power to detect
Lesion yes, imaging, not essential. No activation: compare task w/baseline that also activates, due to difficulties in imaging, or rightfully show area not essential and lesion data for white matter area near by. |
Imaging v. lesion
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Cog neuro in non-human animals (because not know if non-humans think)
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Behavioral Neuroscience
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1. Aspiration: suction out matter and then seal.
2. Transection: cutting white matter bundles *3. Neurochemical lesions-insert toxins. 4. Reversible lesions: meds manipulation |
Ways to selectively produce lesions in animals (4)
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Electromagnetic induction: charge of electric current in coil generates magnetic field. Secondary current induced in brain below stimuation site (caused by generating action potentials)
Timing: Pulse for 1ms, effects can last up to 100ms Effects: motor movements and visual phosphenes |
TMS (Transcranial Magnetic Stimulation)
Definition, timing, effects |
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Area of brain not contribue in ordered way
Behavioral impairments (reaction time) Possible behavioral stimulation |
possible Noise introduced by TMS
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Allow study of normal subjects (without confound of organic)
Minimize plastic reorganization Study multiple subjects with same paradigm Study time course of effects Control size of lesion Able to see baseline and determine upper threshold for lesioning |
Advantages of TMS
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Seizure induction by spreading excitement (Single-only epileptics, rTMS-both)
Cannot do on person with intracrannial metal Need to protect hearing from clicks Potential for local neck/back pain (particularly over frontal and temporal regions) Potential mood effects (uplifting to RPFC) |
Safety with TMS
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Gives timing info only for online TMS
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Single Pulse
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train of pulses. Increase effect, lessen timing info able to get. For both on and offline
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rTMS
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Prior to task: rTMS showed sustained behavior effects
Slow rTMS repetition rate 1 Hz or lower (no more than 1 pulse per sec). W/prolonged, lower future neural firing. rapid rTMS: repetition rate greater than 1 Hz/sec (5-25/sec). W/prolonged, increase future neural firing |
Off-line TMS
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Figure 8/butterfly coil (more common)
Circular coil As go further down, stim more pinpointed (cannot directly stimulate medial or subcortical areas) |
coil geography and depth
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Pascal-braille in early blind. slow rTMS lower reading speed, fast rTMS increase reading speed (compared to control).
Showed causal effect of occipital lobe and braille. |
Example Off-line TMS (braille)
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using rTMS or single pulse during task to disrupt processing.
rTMS look at interference. single pulse takes it further to look at timing info |
Online TMS
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COhen: Braille reading in early blind. rTMS @ 10 Hz for 3 sec when reading braille. Stim at midoccipital site interfered with reading.
Hamilton and Pascal-Leone: one braille letter when to pps w/single pulse TMS. Applied at different intervals after presentation. Either occipital ctx or hand area of sensory ctx. Early-sensory ctx involved in perceiving Braille Later-occiptial ctx involved in identifying what stim is |
Example Online TMS
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Can't do two things at once because shares cog process and can't process both
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Dual task interference
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when lesions improve performance
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Facilitation
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understanding how function of one part of the brain impacts function of another
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functional integration
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one aspect of task hinders performace of another aspect.
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Interference.
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train of pulses. Increase effect, lessen timing info able to get. For both on and offline
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rTMS
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Prior to task: rTMS showed sustained behavior effects
Slow rTMS repetition rate 1 Hz or lower (no more than 1 pulse per sec). W/prolonged, lower future neural firing. rapid rTMS: repetition rate greater than 1 Hz/sec (5-25/sec). W/prolonged, increase future neural firing |
Off-line TMS
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Figure 8/butterfly coil (more common)
Circular coil As go further down, stim more pinpointed (cannot directly stimulate medial or subcortical areas) |
coil geography and depth
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Pascal-braille in early blind. slow rTMS lower reading speed, fast rTMS increase reading speed (compared to control).
Showed causal effect of occipital lobe and braille. |
Example Off-line TMS (braille)
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using rTMS or single pulse during task to disrupt processing.
rTMS look at interference. single pulse takes it further to look at timing info |
Online TMS
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COhen: Braille reading in early blind. rTMS @ 10 Hz for 3 sec when reading braille. Stim at midoccipital site interfered with reading.
Hamilton and Pascal-Leone: one braille letter when to pps w/single pulse TMS. Applied at different intervals after presentation. Either occipital ctx or hand area of sensory ctx. Early-sensory ctx involved in perceiving Braille Later-occiptial ctx involved in identifying what stim is |
Example Online TMS
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Can't do two things at once because shares cog process and can't process both
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Dual task interference
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when lesions improve performance
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Facilitation
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understanding how function of one part of the brain impacts function of another
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functional integration
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one aspect of task hinders performace of another aspect.
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Interference.
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Functional effect: motor-hand twitch
Map from Functional landmark: frontal eye fields 2-3mm anterior to hand area Map from anatomical landmark: V5-5cm from anion moving laterally and 3cm up. **Frameless stereotaxy: use structural/functional MRI to find region, then use software to dictate placement. |
Coil Localization
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1. No TMS (no phys touch or sound)
2. sham TMS-discharge w/o stim. "Air trials" 3. keep stim location constant, change task (control task) 4. Stimulate other site likely to have effect. Here=vertex. |
TMS control conditions
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effects of stimulus on sensory organs
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Sensation
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elaboration and interpretation of sensory info
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Perception
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internal surface of eyes w/specialized photoreceptors transducing (converting) light into neuronal signals
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Retina
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point at which optic nerve leaves the eye.
Info from retina to brain via optic nerve |
Blind spot
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place w/highest concentration of cones, therefore highest level of detail
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Fovea
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ending point of dominant vidual pathway
1st stage of visual processing in cortex-holds spatial relationships found on the retina and combines simple visual features into more complex ones. Travels via Lateral Geniculate Nucleus (LGN) |
Primary Visual Cortex (V1)
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Objects in R visual field fall on L side of retina and project to L LGN. Info segregated in 6 layers. 1,4,6 Nasal field from Contralateral. 2,3,5 Temporal field from Ipsilateral.
Top 2 layers=magno. Bottom 4=parvo Beginning of Geniculostriate Pathway. |
LGN
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Magnocellular (parosol): big, large-dendrite field therefore large receptive field. Fat/large axons Therefore fast conduction. Conveys info on motion, location and depth.
Parvocellular (midget): smaller cells with slower conduction rate. Codes color info in the center-surround design. Carries info on color, form, texture (more fine-grained) |
ganglion cells: 2 kinds
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region of space eliciting response from given neuron
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Receptive Field
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Simple cell: cell responding to light in particular organization.. Integrate across both eyes
Complex cells: Cells responding to light in particular orientation, but across entire region. Hypercomplex cells: cells responding to particular orientation and length outside V1. |
Hubel and Weisel properties of neurons in V1
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10% of info from Optic Nerve. To superior colliculus->pulvinar to other areas.
Older, mapped in frogs |
techtopulvinar system
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90% info from Optic Nerves. LGN->striate area-> other visual areas
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geniculostraite pathway
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cortical blindness in 1/2 visual field (w/damage to Primary visual cortex in one hem.
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Hemianopia
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cortical blindness to 1/4 visual field
Small region of cortical blindness |
Quadrantoanopia
Scotoma |
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when layout in area parallels that found in retina
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Retinotopically organized
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impaired vision and no awareness of vision.
Able to do visual discrim but not consciously see stim. |
Blindsight
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occipital cortex outside V1. becomes broader adn less coherently organized
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Extrastriate Cortex
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region of Extrastriate ctx for color processing
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V4
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region extrastriate cortex for motion perception
Main movement center of brain. w/damage, lose ability to see movement so see world in still frames failure to perceive visual motion |
V5 (MT-medial temporal)
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color of surface considered constant even when illuminated under different condition
produced by V4-by comparing wavelength. Hippocampus also deal with color |
Color constancy
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ability to detect if stimulus is animated by movement cues alone
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Biological cues
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failure to understand object meaning due to deficit at level of object perception
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apperceptive agnosia
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failure to understand object meaning due to deficit in semantic memory (stored visual memory rep)
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associative agnosia
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process of segmenting physical display into objects v background surfaces
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figure ground segregation
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difficulty integrating parts into wholes in visual perception.
Can still group local contours. Not able to recog objects, but able to discriminate length, orientation, and position Case of HJA w/bilateral stroke |
integrative agnosia
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ability to recognize objects across different viewpoints and lighting conditions.
match constructed visual rep with store of object description in memory We typically store objects in typical biew. Combo of matching features and parts to structural descriptions and extracting principle axis of object. Parietal lobe help rotate object to normal view after pick out principal axis. |
Object Constancy
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inability to extract orientation of object despite adequate object recog
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Object orientation agnosia
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takes info from geniculostriate pathway and codes type of info important for object constancy
Neurons code for specific visual info but are less concerned with location of object |
Infero-temporal cortex
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region extrastriate cortex for motion perception
Main movement center of brain. w/damage, lose ability to see movement so see world in still frames failure to perceive visual motion |
V5 (MT-medial temporal)
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color of surface considered constant even when illuminated under different condition
produced by V4-by comparing wavelength. Hippocampus also deal with color |
Color constancy
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ability to detect if stimulus is animated by movement cues alone
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Biological cues
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failure to understand object meaning due to deficit at level of object perception
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apperceptive agnosia
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failure to understand object meaning due to deficit in semantic memory (stored visual memory rep)
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associative agnosia
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process of segmenting physical display into objects v background surfaces
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figure ground segregation
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difficulty integrating parts into wholes in visual perception.
Can still group local contours. Not able to recog objects, but able to discriminate length, orientation, and position Case of HJA w/bilateral stroke |
integrative agnosia
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ability to recognize objects across different viewpoints and lighting conditions.
match constructed visual rep with store of object description in memory We typically store objects in typical view. Combo of matching features and parts to structural descriptions and extracting principle axis of object. Parietal lobe help rotate object to normal view after pick out principal axis. Right temporal cortex (R fusiform area-view dependent) Left temporal cortex (L fusiform area-view invariant)**Shows priming for object irregardless of viewpoint |
Object Constancy
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inability to extract orientation of object despite adequate object recog
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Object orientation agnosia
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takes info from geniculostriate pathway and codes type of info important for object constancy
Neurons code for specific visual info but are less concerned with location of object |
Infero-temporal cortex
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region extrastriate cortex for motion perception
Main movement center of brain. w/damage, lose ability to see movement so see world in still frames failure to perceive visual motion |
V5 (MT-medial temporal)
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color of surface considered constant even when illuminated under different condition
produced by V4-by comparing wavelength. Hippocampus also deal with color |
Color constancy
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ability to detect if stimulus is animated by movement cues alone
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Biological cues
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failure to understand object meaning due to deficit at level of object perception
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apperceptive agnosia
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failure to understand object meaning due to deficit in semantic memory (stored visual memory rep)
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associative agnosia
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process of segmenting physical display into objects v background surfaces
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figure ground segregation
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difficulty integrating parts into wholes in visual perception.
Can still group local contours. Not able to recog objects, but able to discriminate length, orientation, and position Case of HJA w/bilateral stroke |
integrative agnosia
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ability to recognize objects across different viewpoints and lighting conditions.
match constructed visual rep with store of object description in memory We typically store objects in typical biew. Combo of matching features and parts to structural descriptions and extracting principle axis of object. Parietal lobe help rotate object to normal view after pick out principal axis. |
Object Constancy
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inability to extract orientation of object despite adequate object recog
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Object orientation agnosia
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takes info from geniculostriate pathway and codes type of info important for object constancy
Neurons code for specific visual info but are less concerned with location of object |
Infero-temporal cortex
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notion that brain represents different categories in different ways (same concept of domain specificity
Kanwisher (preferred stimuli for specific areas of brain) Parahippocampal place areas (ventral side, temporal lobe) Extrastriate body area (lateral surface, temporal lobe) Fusiform face area |
Category specificity
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One model for face processing: recognize faces by matching them to a store of faces based on structural descriptions
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Face recognition units
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access semantic and name info for the individual and use with face recognition units
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Personal Identity nodes
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Impairment of face processing, not showing differences of early visual analysis.
Or inability to recognize previously familiar faces Damage to FFA Look at with famous face task |
Prosopagnosia
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Process the face as a whole, within a given configuration (found that pps better able to recog nose when in whole face than on own-->found with normal functioning)
R side of brain more holistic and configural |
Holistic processing
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humans are good at discriminating between faces (within category discrimination)
FFA responsive to fine-grained differentiation: Greebles (N170 effect) Look at experts, see activation in R FFA (R side of brain more holistic and configural) |
Visual Expertise
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Kanwisher: domain specificity with specific area for face processing
Gauthier: Visual expertise model saying that humans highly sensitive to experience |
Debate for why faces special-2 people
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ot able to decipher familiar faces from unfamiliar faces. But able to decipher own sheep from others
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Patient WJ issue
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Not able to recognize abnormalities in inverted faces because faces are processed by surface features and global shapes (not piecemeal features)
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Margaret Thatcher Illusion
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Inability to accurately reach towards objects with visual guidance.
From damage to occipito-parietal junction |
Optic ataxia
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What: Temporal (ventral)-for awareness and identification. Bilateral connections-projections from occipital regions in both hemispheres. All receptive fields include fovea
How/Where pathway: parietal (dorsal) vision for action. Unilateral connections with projections form ipsilateral occipital regions. Not include info from the fovea |
"What" v. "how"
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sensory maps of space coded relative to position of the body
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Egocentric space
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sensory map of space coded on eye gaze
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Retinocentric space
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map of space coding the location of one object with relation to the other
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Allocentric space
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Integrating info across sensory modalities. Space helps to prioritize info in terms of processing
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Cross-modal perception
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Process of certain information being selected for further processing and other information being discarded.
Need to do to avoid sensory overload. Thinking of external stimulus being transduced into brain |
Attention
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Cat and music study. Found that need to keep the signal input to sensory receptors constant, only varying attention (if move head, change access to stim)
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Hernandez-Peon study
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Endogenous Cuing: Cue giving for upcoming target
Arrow to place where cue (valid). Found that people faster w/valid cues compared to control. Exogenous Cuing: Cue captures attention but doesn't give info on task being performed Flash on one side of screen. Facilitation if before 200ms. See Inhibition of Return after 300ms. |
Posner Paradigm (w/Type of cuing)
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Inability to return to previously attended stimuli after certain time period
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Inhibition of Return
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Task detecting presence/absence of specialized target object in array of distracting objects
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Visual search
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Not consciously seeing something because attention is directed elsewhere
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Inattentional Blindness
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When participants fail to notice the appearance/disappearance of object between two alternating images
Look at brain areas involved with flicker paradigm: two pictures flickering between. Need to state differences. fMRI study found that when detect changes, activated parietal and dorslateral frontal cortex. online TMS found largest deficit to parietal cortex. |
Change Blindness
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Effects of voluntary visual attention at LGN and striate cortex very EARLY IN PROCESSING
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Spatial visual attention in fMRI
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Brain activity in response to endogenous cue. See bilateral, fronto and parietal attentional network.
When voluntary, still get fronto and parietal activation. Auditory P20-50 effect (earlier processing) |
Attentional Control Network
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Perceptual features (color, shape, etc) coded in parallel and before attention. As increase distractors, must process several features at one so must allocate spatial attention to candidate objects in turn.
(Need attention to bind properties into one object) Conjunction search time increases as number of distractors increases |
Feature Integration Model (FIT)
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Single Search Features (pop out): No difference in target search reaction time with more features if just looking at one feature
Conjunction search: Looking at multiple distractors, as they increase, so does reaction time. |
Target search methods/reactions
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Visual features of two objects incorrectly perceived as one object
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Illusory Conjunction
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Found attention modulated activity in feature specific extrastriate cortex.
V4 for color. V5 for motion |
Study: Schoenfeld
Feature based visual attention results |
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Theory of attention where info is selected according to perceptual attributes
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Early Selection Model
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Theory of attention where info is processed up to the point of meaning (semantics) before selection for continued processing.
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Late Selection Model
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When ignored object suddenly becomes attended object therefore slower processing
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Negative Priming Effect
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tendency to mislocalize heard sounds onto seen source of potential sound
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Ventriloquist Effect
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Severe problem with spatial processing normally following bilateral lesions of parietal lobe.
Includes simultanagnosia: Only able to perceive one onject at a time Optic ataxia: inability to reach for an object. Object apraxia: inability to fix eye gaze Patient RM: Not able to ocate objects verbally or by reaching/pointing. Still had spatial frames, proving different mechanisms for body and external space |
Baliants Syndrome
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Failure to attend to one side of space due to lesion on opposite hemisphere.
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Hemineglect
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Theory of attention where info is processed up to the point of meaning (semantics) before selection for continued processing.
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Late Selection Model
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When ignored object suddenly becomes attended object therefore slower processing
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Negative Priming Effect
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tendency to mislocalize heard sounds onto seen source of potential sound
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Ventriloquist Effect
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Severe problem with spatial processing normally following bilateral lesions of parietal lobe.
Includes simultanagnosia: Only able to perceive one onject at a time Optic ataxia: inability to reach for an object. Object apraxia: inability to fix eye gaze Patient RM: Not able to ocate objects verbally or by reaching/pointing. Still had spatial frames, proving different mechanisms for body and external space |
Baliants Syndrome
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Failure to attend to one side of space due to lesion on opposite hemisphere.
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Hemineglect
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Line bisection task: must bisect line at midpoint. Misplace to right
Cancellation task: variant of visual search. Search for targets and strike out as found. Only get objects to right |
Tests for Neglect
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When presented with stimulus at same time in different hemispheres, tim on opposite side of lesion not consciously perceived.
PPs impaired if first cued in affected area invalidly (possibly due to issues disengaging from unaffected field) Finger flicking task: able to do each side separately. W/both sides, stim in impaired field extinguished from awareness. |
Extinction
Extinction like Voluntary Cuing Effect Finger Flicking and Extinction |
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artist with stroke to R Hemisphere. His paintings ignored the left side of the canvas and left side of picture. Improved over time.
After RH stroke, 80-90% have neglect. Many improve over time |
Anton Raederscheidt
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Representative system for coding space
Near v. far External v. Internal Personal v. Peripersonal v. Extrapersonal |
Reference Frames
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Left Hemisphere: Strong bias to RVF
Inhibits RH Damage to: Remove RH inhibition but RH still attend to both sides Right HemL Moderate bias to LVF, also attend to RVF. Inhibits LH Damage: lessens ability to attend LVF Removes inhibition of LH and stronger LH further reduces RH functioning |
Attentional biasing model
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