psych 3315 exam 2 pt 2

What is Bálint’s syndrome

Bilateral occipitoparietal damage causing simultanagnosia, ocular apraxia, and optic ataxia.

What is unilateral spatial neglect

Failure to attend to contralesional space after unilateral brain lesion.

What spatial bias occurs in neglect

Attention biased toward ipsilesional side.

What is extinction

Failure to perceive contralesional stimulus when bilateral stimuli appear simultaneously.

Voluntary attention definition

Goal-directed, intentional attention.

Reflexive attention definition

Stimulus-driven automatic attention.

Overt attention

Attention with observable eye movements.

Covert attention

Attention without eye movements.

What does the dichotic listening task demonstrate

Selective attention and limited processing capacity.

What is an attentional bottleneck

Stage where only limited information can pass.

Broadbent’s early-selection model

Early sensory filter allows only selected information for further processing.

Early selection theory

Filtering occurs before perceptual analysis.

Late selection theory

All stimuli processed before selection.

Valid cue in Posner task

Cue correctly predicts target location; faster responses.

Invalid cue in Posner task

Cue misdirects attention; slower responses.

Endogenous cuing

Voluntary attention controlled internally.

Exogenous cuing

Reflexive attention triggered externally.

ERP effect of voluntary attention

Increased occipital P1 amplitude.

Role of TRN

Inhibits LGN to select attended visual information.

Inhibition of return

Slower responses to previously attended locations.

Feature search

Target pops out via single feature difference.

Conjunction search

Requires focused attention to combine features.

Feature Integration Theory

Attention binds separate visual features into objects.

Feature attention

Attention directed to stimulus features.

Object attention

Attention spreads across an entire object.

Evidence for object attention

Object-specific brain activation (FFA/PPA).

Role of frontal eye fields

Control voluntary orienting and eye movements.

Role of superior colliculi

Reflexive orienting and visuomotor control.

What is an effector

Any body part capable of movement.

Role of alpha motor neurons

Directly cause muscle contraction via ACh release.

Function of spinal interneurons

Integrate descending motor signals and influence motor neurons.

Muscle spindles detect what

Muscle stretch and length.

Stretch reflex purpose

Automatic regulation of muscle contraction.

Corticospinal tract function

Voluntary movement control from cortex to spinal cord.

Pyramidal vs extrapyramidal difference

Direct voluntary control vs indirect modulation pathways.

Vestibulocerebellum function

Balance and eye movement coordination.

Spinocerebellum function

Sensory-guided movement control.

Neocerebellum function

Skilled voluntary movement coordination.

Special role of SMA

Sequential and well-learned movements.

Ataxia

Clumsy movement from cerebellar damage.

Apraxia

Loss of skilled movement without weakness.

Ideomotor apraxia

Cannot properly execute known action.

Ideational apraxia

Loss of understanding of action purpose.

Intention tremor

Tremor during movement.

Resting tremor

Tremor at rest.

Center-out task shows

Motor cortex neurons encode movement direction before movement.

Basal ganglia gatekeeper role

Prevent unwanted movements until selected plan wins.

Substantia nigra function

Dopamine supply for movement initiation.

Hemiplegia

Paralysis on one side of body.

Central pattern generators

Spinal circuits producing rhythmic movement without brain input.

Endpoint control

Movements planned based on final position

Preferred direction

Movement direction producing highest neuron firing.

Population vector

Combined neural activity predicting movement direction.

Affordance competition hypothesis

Multiple possible actions compete simultaneously.

Alien hand syndrome

Limb acts independently of conscious control.

Brain-machine interface

Uses neural signals to control external devices.

Huntington’s disease

Hyperkinesia from striatal degeneration

Parkinson’s disease

Dopamine loss causing movement initiation problems.

Hypokinesia

Reduced movement.

Bradykinesia

Slow movement initiation.

Mirror neurons

Fire during both action execution and observation.

Role of mirror neurons

Link perception and action understanding

Role of pulvinar

Filtering stimuli and supporting covert spatial attention.