GABAERGIC RETINOCOLLICULAR PROJECTION IN THE NEW-WORLD MONKEY CEBUS-APELLA

GABA immunoreactivity was examined in the retina of the New World monk ey Cebus apella. Labeled cell bodies were identified as horizontal, bi polar, interplexiform, amacrine and a population of putative ganglion cells. To determine whether ganglion cells were immunoreactive to GABA , double-labeling experiments were performed using Fast Blue as retrog rade neuronal tracer injected into the superior colliculus. Retinas co ntaining FB-labeled ganglion cells were subsequently incubated with an tiserum against GABA. Although retinocollicular ganglion cells were fo und in three different layers (ganglion cell layer, inner nuclear laye r and inner plexiform layer), our experiments revealed GABA-positive g anglion cells only in the outer half of the ganglion cell layer.