Neuronal Activity in the Afferent Visual System and Monocular Pattern Deprivation

Abstract

In a paper entitled “The loss of a specific cell type from dorsal lateral geniculate nucleus in visually deprived cats,” Sherman, Hoffmann, and Stone (1972) described the probability of recording from Y-cells in layer A or A1 of the cat LGN being reduced for the respective layer connected with the deprived eye (monocular deprivation). Several years ago, while recording from single neurons in the visual cortex or the optic radiation (OR) of monocularly deprived animals, we found that monocular deprivation did not change the relative distribution of latency class I (Y) or latency class II (X) neurons in the neuronal samples recorded from the OR. Because these findings seemed to contradict the data published by Sherman, Hoffmann, and Stone, a more extensive study was performed in a larger population of neurons in five adult cats which had undergone monocular deprivation since the second week of life (Eysel, Grusser, and Hoffmann, 1978, 1979). In two animals, some of the recordings were obtained before the eyelids of the deprived eye were opened. Single neurons were recorded in the optic tract (OT), the lateral geniculate body (pars dorsalis, layer A and A1; LGN) and the OR by means of tungsten microelectrodes (pentobarbital anaesthesia). The neurons were classified as Y- or X-neurons according to their visual response properties to light on-off, grid patterns moved through the RF, flicker responses and receptive field sizes relative to the position of the RF in the visual field or as class I or class II neurons by their latencies evoked by electrical optic tract stimulation.