Vision (Neuroscience)

Anatomy §

1. Photoreceptors in Retina
   1. Cones (color) and Rods (Sensitivity)
2. Optic Chasm
3. Both:
   1. Lateral Geniculate Nucleaus (LGN) $\subset$ Thalamus
   2. Superior Colliculus (unconscious brain movements)
4. from LGN → Visual cortex

Biological built-in hardware feature: Lateral inhibition. Sharpens contrast in the border regions. Happens in the retina itself

• The bipolar cells (the final signal) get input from photoreceptors
• Horizontal cells inhibit, but this inhibition decays with distance
• Final signal emphasizes edges

Processing §

Visual Cortex: V1, V2

• Simple cells: Simple kernel, looks like the shape itself
• Complex cells: orientation of shape
• Hypercomplex cells: Endstopped → Feature detectors

Development §

Parallel Processing §

from V2:

• V3, V4, …
• Ventral Stream: object recognition,
• Dorsal Stream: 공간지각력,
  • At Inferior-Temporal Cortex
  • Includes fusiform gyrus: specialized for face-recognition + similar things
• Motion Detection by
  • V5: Middle Temporal Cortex (MT)
  • Medial Superior Temporal Cortex (MST)
  • During Saccades, they stop working