| Abstract: | We recorded the activity of two types of granular cells in the rostral folia of the paramedial lobe (the projection region of the front legs) of the cerebellar cortex in cats immobilized by administration of ditiline; these cells differed in their receptive fields, the characteristics of their reaction to single stimulation of somatic nerves, and the character of their background activity. The granular cells of the first type were excited only when the nerves of the front legs were stimulated (reacting with 1–3 impulses with a latent period of 8–20 msec) and were inhibited between 20–50 and 70–180 msec after stimulation of the nerves of any leg. The cells of the second type responded with volleys of 3–6 impulses with a latent period of 20–40 msec to stimulation of the nerves of all four legs. Comparison of the reactions of the granular cells and other neurons of the cerebellar cortex showed that the cells of the first type cause excitation of the Purkinje and Golgi cells and the neurons of the molecular layer. The granular cells of the second type have an excitatory effect on the Golgi cells. The differences in the reactions of the two types of granular cells result from the fact that they are selectively innervated by the mossy fibers of different afferent pathways. Comparison with the data in the literature enables us to surmise that the fibers of the cuneocerebellar tract terminate at granular cells of the first type, while the reticular fibers terminate at cells of the second type.Institute of Problems of Information Transmission, Academy of Sciences of the USSR, Moscow. Translated from Neirofiziologiya, Vol. 1, No. 2, pp. 167–176, September–October, 1969. |
