visual perception and recognition

Sensation

When something stimulates a sensory organ

Perception

the process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events

Shape constancy

the tendency to interpret the shape of an object as being constant, even when its shape changes on the retina

color constancy

perceiving familiar objects as having consistent color, even if changing illumination alters the wavelengths reflected by the object

size constancy

the tendency to interpret an object as always being the same actual size, regardless of its distance

The cortical system is organized into three visual pathways that begin with occipital cortex

Ventral pathway, dorsal pathway, and lateral pathway

Ventral pathway

Pathway of visual processing. The "what" pathway. Starts in occipital cortex V1-V4.

Dorsal pathway

Projects to the parietal cortex and is involved in perceiving the location of objects // vision for action

Lateral pathway

Superior temporal lobe , supports social perception

Posterior areas represent

Simple features

Eye to primary visual cortex

Composed of V1-V4, fovea and periphery

Fovea

the central focal point in the retina, high acuity and object perception

Periphery

Towards outside of eye , low acuity , essential for navigation

info from left visual field goes to…

right side of the brain

Foveal info represented in

Posterior (back) V1

Peripheral info represented in

Anterior V1

Upper info represented in

Ventral (Bottom) V1

Lower info represented in

Dorsal (top) V1

Receptive field of a visual cell

neurons that respond to specific visual stimuli in the retinal area

Anterior areas

Form real objects from abstract concepts , more complex features

Object agnosia

Has basic visual processes but cannot make sense of objects, common in stroke pts caused by posterior it damage. Intact occipital lobe.

associative visual agnosia

Normal visual acuity , can match objects but has trouble naming them. Caused by anterior IT damage. Intact occipital and posterior IT.

concept cells

Cells, such as those found in the anterior temple lobe that respond to ideas or concepts rather than to particulars. Also known as Jennifer Aniston neurons

Temporal lobe

Object recognition

Parietal lobe

Spatial awareness

Feedback Processing

Info from higher levels flows down to lower levels (top down) , helps give context use knowledge to support perception

Feedforward processing

Info sent up the hierarchy , lower to higher levels (bottom up processing)

modular organization

Brain contains distinct regions to support processing for different information or functions. Each region is specialized to support one type of information.

Continued/Distributive organization

Info is represented across the cortical area

Prosopgnosia

inability to recognize faces, caused by damage to the fusiform face area (ffa)

Anterior temporal lobe

Abstract concepts

Object agnosia is caused by ________ damage

Posterior IT

Associative visual agnosia is caused by _______ damage

Anterior IT

Dorsal pathway location

Along the parietal

Lateral pathway location

Superior temporal lobe

Ventral pathway location

IT (inferior temporal) lobe