What & Where Pathways

What and Where visual Pathways presentation by Optom Girma Shallo

2. What and Where pathway 2

6. The Visual Projection Pathway

Left visual field Right visual field

Left eye Right eye

Optic chiasm

Pretectal

Lateral
nucleus

geniculate
nucleus of the
thalamus
Superior

colliculus

Left Right
cerebral 7 cerebral
hemisphere J hemisphere

8. The Visual Pathways (Streams)...

+ The two functionally and anatomically distinct visual processing

pathways (streams) originating in the occipital cortex are:

1. The What pathway ("ventral stream")

2. The Where pathway ("dorsal stream")

9. What and Where pathways

10. What pathway

Primary visual cortex
‘Secondary visual cortex
inferotemporal area

Posterior partial area

20. = Spatial disorders due to damage to the posterior parietal cortex:
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23. Also called ventral stream

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| Originates in primary visual cortex
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Kar o,

| Extends along the ventral surface

Leads into the temporal cortex

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Recognition/identification of objects

Neurons respond to visual features needed

for object identification

Also called dorsal (how) stream
Originates in primary visual cortex
Extends along the dorsal surface
Leads into parietal cortex

Visually guided behavior

Neurons respond to spatial stimuli

24. What and Where pathway... 24