Response characteristics of cerebellar nuclear cells in the pigeon

In birds, the output system of the cerebellum, the cerebellar nuclei, has not yet been studied electrophysiologically. Recordings from nuclear cells during electrical stimulation of the radial nerve revealed a uniform type of response consisting of an initial inhibition followed by a clear cut excitation. Responses with an initial excitation were rare. Response patterns and latencies suggest an input from Purkinje cells of the cerebellar cortex and a lack of collateral input from spinocerebellar pathways. This points to a fundamental difference from cerebellar nuclear cells in mammals, in which collateral input provides a prominent excitatory response under comparable experimental conditions.