Development of cytochrome oxidase staining in the retina and lateral geniculate nucleus: a possible correlate of ON- and OFF-center channel maturation.

A histochemical stain for cytochrome oxidase (CO) activity was used to examine the maturation of a neurochemical correlate of ON and OFF channels in the retina and dorsal lateral geniculate nucleus (LGN) of the tree shrew. In the adult tree shrew, the CO staining pattern can be used as a histochemical marker of segregated ON- and OFF-center channels in the retina, LGN, and striate cortex. Our previous studies have shown that the retina is immature and the LGN unlaminated at birth. In the present study, we show that the laminar development of CO reactivity emerges during the first postnatal week in the LGN, while the maturation of CO staining in the presumed ON and OFF sublaminae of the retinal inner plexiform layer develops slowly, well after the appearance of differential laminar CO staining in the LGN.