| Abstract: | A comparison was made of the characteristics of the background and light-induced impulse activity of 350 neurons of the retina and laterial geniculate body (LGB) of an immobilized cat. In the LGB, in contrast to the ganglion cells of the retina, there are relatively more neurons with high-light sensitivity, low latency of response, short-initial discharge, and low summation time, as well as rapid recovery of reactivity. It was found that these changes are characteristic of cells connected with the peripheral region of the retina. In the central channel and the system of long-latency cells, according to a number of parameters, no such transformations are found, while other characteristics change in the opposite direction. In the central channel at the postgenicular level, the frequency of the background and induced impulsation decreases, while in the peripheral channel it increases considerably. The results obtained indicate differences in the organization of the synaptic inputs of LGB neurons of different groups. The intensification and time compression of the sensory transmission in the peripheral channel are explained by the reticular properties of the structures formed by the branching and overlapping fibers coming from the retina, as well as by the great effectiveness of the successive inhibition in the LGB which blocks the late group of initial discharges. These transformations of the afferentation can provide reliability and rapidity of the detection of weak, slowly increasing, and moving light signals.Institute of Higher Nervous Activity and Neurophysiology, Academy of Sciences of the USSR, Moscow. Translated from Neirofiziologiya, Vol. 3, No. 1, pp. 13–21, January–February, 1971. |
