Figure 6.

A) A parasagittal section of ferret lateral geniculate nucleus reacted for cytochrome c oxidase. Sublaminae A′ and A1′ representing the OFF-pathway have higher enzyme levels than the ON-sublaminae A and A1. Magnocellular lamina C (Cm) is also more reactive than the parvocellular lamina C (Cp). The perigeniculate nucleus (PG) is only lightly labeled. B) Coronal section of the macaque LGN reacted for cytochrome c oxidase. The pattern of metabolic activity probably reflects a combination of greater functional activity in a) the magnocellular layers 1 and 2 than the parvocellular layers 3–5; b) the ON-pathway-dominant layers 5 and 6 than the OFF-pathway-dominant layers 3 and 4; and c) the contralateral pathway in layers 1 and 6 than the ipsilateral pathway in layers 2 and 5. Modified with permission from Kageyana and Wong-Riley 1984.⁵³