Visual Pathway

Visual Pathway

1. Visual field: everything that can be seen when the eyes are forward, including peripheral vision

   • Light that strikes the nasal half of the eye will be transmitted contralaterally via the optic chiasm.
   • Light that strikes the temporal side of the eye will be transmitted by the same side of the brain

2. Information processing

   • Relatively basic at visual cortex: contrast information & object orientation
     • Provides form, colour & motor inputs to other visual association areas

3. Visual cortices

   • Primary visual cortex (V1, Brodman area 17)
     • Occupies upper & lower lips of calcarine sulcus
     • Input from LGN (thalamus), output to other areas
   • V2: perception of form
   • V4: perception of colour
   • V5: perception of motor

4. Vision loss

   • Unilateral - mainly in front of optic chiasm
   • Bilateral: mainly behind optic chiasm