Wavelength and intensity effects on the response of single lateral geniculate nucleus units in the owl monkey.

Abstract

Electrophysiological studies with semi-microelectrodes and microelectrodes were carried out to determine the functional organization of the lateral geniculate nucleus (LGN) and the spectral sensitivity of the retinal elements as reflected in the activity of single LGN units. Microelectrode recording revealed cells which responded either by decreasing their rate of activity or increasing their rate of activity and were classed as broad band inhibitors or broad band on cells. The spectral sensitivity plots of 143 cells reflected 3 classes of cells with peak sensitivities at about 500, 530, and 560 m[mu]. The spectral sensitivity peak of each cell was determined by fitting against 22 templates, constructed from Dartnall''s (1953) nomo-gram for visual pigments, with [lambda] max at 5 m[mu] intervals and determining which template best fit the data points. Analysis of the individual unit spectral sensitivity and the summed spectral sensitivity of all units indicated that more than one pigment was contributing to the luminosity functions of the owl monkey.