Vision

Vision

1. primary visual pathway

   • 5 components
     • optic nerve
     • optic chaism
       • retinal ganglion cells have long axons that lead to lgn
     • LGN
       • Lateral geniculate nucleus
     • optical radiations
     • VI
       • visual cortex
   • input goes through the thalamus then to the cerebal cortex

2. colour opponent cells in LGN

   • M cells
     • recieve input primarily from cones
     • pathway for detecting contrast and motion, low-light vision
   • P cells
     • pathway for high-acuity vision
     • recieve input primarily from cones

3. retinatopic maps in v1

   • left hemisphere contains maps of right visual field
   • right hemisphere contains maps of left visual field
   • upper half contains maps of lower visual field

4. effects of V1 damage

   • blindness in area associated with damage
     • e.g damage to the left = blind in the right
   • visual capacity in blind space called blindsight

5. effects of visual deprivation

   • casestudies
     • loss of sight as a child = regained sight as an adult
   • hallucinations