Psych 3513 exam 2

What is the Wada Test?

A procedure to determine hemispheric dominance for language by anesthetizing one hemisphere

What is a homotopic area?

Corresponding areas in both hemispheres

What is a heterotopic area?

Different areas across hemispheres

What is an ipsilateral area?

Same-side connections within in a hemisphere

What are the parts of the corpus callosum?

Genu, body, and splenium

What is the function of the commissures?

They connect two hemispheres of the brain for communication

What is the proposed function of GABA in the corpus callosum?

It may help regulate interhemispheric communication by inhibiting excessive signaling

What are the functional consequences of the split-brain procedure?

Loss of interhemispheric communication, affecting tasks like language processing and visuospatial perception

How is language and speech lateralized

Typically in the left hemipshere

What is the role of the right hemisphere (where function is primary) in visuospatial processing?

Specializes in spatial awareness and facial recognition (can function without input from left hemisphere)

What is the Interpreter function of the left hemisphere?

The left hemisphere creates explanations for actions and experiences (speech) (right hemisphere initiates actions)

What does the Dichotic Listening Task show?

It demonstrates hemispheric dominance in auditory processing.

global processing

overall picture

local processing

the fine details

What is lateralization of visuospatial processing?

It refers to the tendency for one hemisphere of the brain to be more involved in processing visuospatial information.

How does the left hemisphere connect to the face in terms of visuospatial processing?

The left hemisphere connects directly to the face.

How does the right hemisphere connect to the face in terms of visuospatial processing?

The right hemisphere has an indirect path to the face through the corpus callosum.

Hierarchical structure

a configuration that may be described at multiple levels from global features to local features

Theory of Mind

refers to ability to understand that other individuals have thoughts beliefs and desires.

Theory of Mind in split-brain patients

Differences moral reasoning: right hemisphere is for fast automatic processing of belief attribution and left hemisphere is slower, more deliberate reasoning mechanisms

hemispheric specialization in non-humans

-Almost all optic fibers cross to contralateral hemisphere

-No corpus callosum

-Categorization: RVF

(LH)

-->(E.g., discriminating food)

-Localization: LVF (RH)

modules/modularity

-modules: a specialized processing unit of the nervous system

--> hypothesized to performs specific computations

(e.g., dedicated modules for speech perception, distinct from auditory perception)

-local specialized networks which can perform unique functions & adapt or evolve to external demands

What does the right hemisphere understand in terms of language?

The right hemisphere understands language, but not syntax.

What is a limitation of the right hemisphere in terms of inference?

The right hemisphere has a limited ability to make inferences.

How does the right hemisphere perform in unfamiliar face recognition?

The right hemisphere is better at unfamiliar face recognition.

What type of processing is mostly right lateralized?

Processing of emotional content appears mostly right lateralized.

What do patients with right temporoparietal damage struggle with regarding language?

Patients with right temporoparietal damage interpret meaning of language, but not emotional prosody.

What is the term for the phenomenon where two cognitive functions are shown to be independent?

Double dissociation.

What percentage of right-handers are left-hemisphere dominant for language?

96%

What percentage of left-handers are left-hemisphere dominant for language?

60%

What percentage of brains have a larger planum temporale in the left hemisphere?

65%

What area of the brain houses Wernicke's area?

Planum temporale

What type of processing is associated with the left hemisphere related to language?

Syntax processing

What type of processing involves understanding meanings of things in the left hemisphere?

Semantic processing

What cognitive function does the left hemisphere facilitate related to reasoning?

Makes logical inferences

Which side of the body is primarily controlled by the left hemisphere for motor action?

Right side

Which visual field is processed by the left hemisphere?

Right visual field

What is agnosia?

A condition where individuals lose the ability to recognize objects, sounds, or smells despite normal sensory function

What is visual agnosia?

The inability to recognize objects visually while still being able to see them

What are the two streams in the Two-Stream Hypothesis?

Ventral and Dorsal

Ventral Stream

what pathway, identifies objects (inferiotemporal cortex)

Dorsal Lobe

where pathway, processes spatial location and movement (posteroparietal cortex)

Evidence for two streams

single cell recording, PET, lesion/behavioral study, optic ataxia, bilateral fMRI activity

What is optic ataxia?

inability to use vision to guide movements (visual agnosia is inability to recognize objects)

What is object constancy?

The ability to consistently recognize an object despite significant changes in appearance (viewing position, illumination, surrounding environment)

View dependent frame of reference

recognition depends on stored perspectives of an object

View-invariant frame of reference

recognition relies on abstract representations that generalize across viewpoints

What does the Repetition Suppression Effect demonstrate?

A reduced neural response when an object is presented repeatedly, indicating familiarity and efficient processing

Grandmother cell hypothesis

individual neurons respond to specific objects or faces

Ensemble encoding hypothesis

object recognition arises from the combined activity of multiple neurons encoding different features

What does the unusual views test assess?

The ability to recognize objects from different angles (different viewpoints of the same object)

What does the shadows test asses?

The ability to recognize objects with altered lighting and shading (objects under normal vs shadowed illumination)

3 types of agnosia

apperceptive, associative, integrative

Integrative agnosia

inability to integrate parts into a whole

Associative agnosia

failure to link perception with meaning

Apperceptive agnosia

difficulty perceiving object structure

What is alexia?

inability to read, recognize written words

Matching-by-Function Test

used to determine if patients can categorize objects based on function rather than apparance

Category-specific deficit in object recognition

when patients have difficulty recognizing specific types of objects, certain class (ex. living vs nonliing things)

Category-based organization

objects recognized based on semantic categories (ex. animals vs tools)

Property-based organization

objects recognized based on shared properties (ex. shape, color, texture)

Prosopagnosia

the inability to recognize faces despite normal vision

What brain area is associated with face recognition?

Fusiform Face Area in the fusiform gyrus

Fusiform face area

functionally defined area of the brain, located on ventral surface of temporal lobe in fusiform gyrus, responds to selective stimuli such as faces

Fusiform gyrus

activated when people view face stimuli, along ventral surface of the temporal lobe

Analytic processing

perceptual analysis that emphasizes the component parts of an object

Holistic processing

perceptual analysis that emphasizes overall shape of object

-face perception reflects the whole

parahippocampal place area (PPA)

area located in parahippocampal region of the temporal lobe that responds to stimuli depicting scenes or places

extrastriate body area (EBA)

involved in action perception (body part movement)

fusiform body area (FBA)

Both the FBA and the EBA may be involved in integrating the color, motion, and shape of body parts

What is the purpose of decoding models in object recognition?

using brain activity which is produced by a stimulus and detected by such methods as fMRI, in order to determine the original stimulus

Balint's syndrome

severe disturbance of visual attention and awareness, inability to focus attention on individual objects, caused by bilateral damage to regions of the posterior parietal and occipital cortex

Unilateral spatial neglect

A failure or slowness in acknowledging object or events in the hemispace contralateral to the lesion (worse when damage ti the right parietal cortex)

How does gaze bias affect neglect position?

Patients fixate more on the right side of a visual scene and ignore the left side

Phenomenon of excitation

failure to perceive or respond to a stimulus contralateral to a lesion ("contralesional") when presented with simultaneous stimulus ipsilateral to the lesion ("ipsilesional")

voluntary attention

goal directed, ability to intentionally attend to something (ex. book), top-down

reflexive attention

stimulus driven process where sensory event captures our attention, bottom-up

overt attention

observable actions relates to attention (eyes direction)

covert attention

unobservable attention

Dichotic listenting task

a task where different messages are played in each ear while the subject attends to one, demonstrates selective auditory attention and lateralization of processing

bottleneck phenomenon

a stage of processing where not all of the inputs gain access or pass through

What does Broadbent's Early-Selection Model propose?

Information is filtered at an early stage based on physical characteristics before semantic processing occurs.

Early-selection model

sensory gating mechanism - only select stimuli even make it to perceptual analysis (top-down)

Late-selection model

everything is encoded and perceptually processed before selection (bottom-up)

Posner's curing paridigm

A task that measures attention shifts using valid, invalid, and neutral cues to direct attention.

endogenous curing

control of attention by internal stimuli under voluntary control (spatial curing paradigm)

exogenous (reflexive) curing

control of attention by external stimuli and not by internal voluntary control

What are ERP components related to voluntary spatial attention?

Increased neural activity in sensory areas for attended stimuli, showing enhanced processing of relevant information

Biased competition model

When different stimuli fall within the receptive field of a neuron, bottom-up signals compete for control of firing.

Thalamic reticular nucleus (TRN) and Perigeniculate nucleus

modulate sensory input and help regulate selective attention by filtering unnecessary stimuli

Inhibition of return (IOR)

slowing of motor responses observed over time when attention is reflexively attracted to a location by a sensory event

Feature targets

"Pop Out" at you

Conjunction targets

you have to look for it

Feature Integration Theory

the idea that the visual system can process in parallel elementary features such as color, shape, and motion, but requires spatial attention to bind the features that define an object (visual search is most rapid)

Feature attention

selectively attending to spatial locations leads to changes in our ability to detect responses to stimuli

-objects are defined by their collection of elementary features

-attention can be directed in advance to spatial locations and nonspatial features

What is object attention?

Object attention involves using stimuli with a mixture of spatial and object processing.

What does the FFA area study indicate?

There are known areas in the brain that selectively respond to faces (FFA) and houses (PPA).

What were the findings regarding brain activity in O'Craven et al. (1999) study?

There was an increase in FFA when attending to faces, an increase in PPA when attending to houses, and an increase in MT for movement.

Frontal Eye Field

controls voluntary eye movements and attention shifts

Superior Colliculi

midbrain structures that receive input from the retinal system and are interconnected with the subcortical and cortical systems