5.3 Parallel Processing in Visual Cortex

what are the major areas of the visual cortex and where are the located

V1 - primary visual cortex

V2, V3, V4 → perception

(v2 & v3 above v1)

v4 bottom

V5 - MT

IT cortex = inferotemporal

reciprocal connections → bidirectional

visual cortex parallel pathways

dorsal stream

ventral stream

dorsal stream

• parietal cortex

• the “how/where” pathway

• visually guided movements

• ex: distances, spacial relationships

ventral stream

• temporal cortex

• the “what” pathway

• identifying & recognizing objects

• ex: people around you

IT cortex

• inferior temporal cortex

• temporal lobe

• visual object recognition and the processing of visual information related to color and form

fusiform gyrus

• specialized to recognize human faces

• part of the inferior temporal cortex

optic ataxia

damage to ventral stream

loss of ability to identify objects

emotional perception

• V5 → MST/MT

dorsal: expansion, contraction, or rotation of visual stimulus

ventral: smth moving in the background

V5 damage

motion blindness

• inability to determine direction, speed, if objects r moving

hemiakinetopsia

motion blindness on one side