Journal of Neuroscience, Vol 15, 689-698, Copyright © 1995 by Society for Neuroscience
Visual deprivation does not affect the orientation and direction sensitivity of relay cells in the lateral geniculate nucleus of the cat
Y Zhou, AG Leventhal and KG Thompson
Department of Biology, University of Science and Technology of China, Hefei, Anhui, People's Republic of China.
Visual deprivation in early life profoundly affects the characteristic
sensitivity of visual cortical cells to stimulus orientation and direction.
Recently, relay cells in the lateral geniculate nucleus (LGNd) have been
shown to exhibit significant degrees of orientation and direction
sensitivity. The effects of visual deprivation upon these properties of
subcortical cells are unknown. In this study cats were reared from birth to
6-12 months of age in total darkness; the orientation and direction
sensitivities of area 17 (striate cortex) and LGNd cells were compared. All
cells were studied using identical quantitative techniques and statistical
tests designed to analyze distributions of angles. The results confirm
previous work and indicate that the orientation and direction sensitivities
of cells in area 17 are profoundly reduced by dark rearing. In marked
contrast, these properties of LGNd relay cells are unaffected. The result
is that, unlike in the normal cat, in dark-reared cats the orientation and
direction sensitivities of cells in the LGNd and visual cortex do not
differ. It is concluded that (1) the orientation and direction
sensitivities of cortical cells contribute little, if at all, to the
sensitivities of LGNd cells since LGNd cells exhibit normal sensitivities
even though the cortical cells projecting to them exhibit greatly reduced
sensitivities and (2) during normal development intracortical mechanisms
appear to expand upon and/or modify the weak orientation and direction
sensitivities of their inputs. These intracortical mechanisms depend upon
normal visual experience since in dark-reared cats, but not normal ones,
the orientation and direction sensitivities of cells in the LGNd and visual
cortex do not differ quantitatively or qualitatively.