S&P 8 - LGN and V1

how many layers in LGN?

6; 1-2 are magnocellular (MLGN), 3-6 are parvocellular (PLGN)

koniocellular layers

sublayers within and between layers

(K, 1K, 2K…; 4A, 4B, 4C⍺, 4Cβ)

midget, parasol, bistratified retinal ganglion cells

magnocellular layers receive input from parasol cells

parvocellular layers receive input from midget cells

lesioned PLGN

difficulty perceiving color and form

lesioned MLGN

difficulty perceiving movement and flicker

retinotopic mapping

objects close in visual field are close in retina and stimulate close neurons in LGN (and v.v.). location of neural activity can give info about location of stimulus

cortical magnification

retinotopic map devotes more space/volume to areas close to fixation point and less to areas in periphery. due to high cone density in fovea

ocular dominance columns

layers in each LGN get info from different layers in each eye

orientation columns

location of neural activity provides info about orientation of stimulus

location columns

location of neural activity provides info about location of stimulus