Discharge patterns of Purkinje cells activated through the climbing fiber system by stimulation of somatic and visceral afferents

Extracellular recordings were obtained from single Purkinje cells (PC) in the intermediate part of the lobule V and VI of the cerebellar cortex in cats anaesthetized with Nembutal. A number of PC responded with a complex spike (CS) to stimulation of both the superficial radial nerve (SRN) and the vagus nerve (VN). By suppressing the transmission of mossy fiber (MF) inputs through manipulation of the level of anaesthesia, attention was paid to the simple spike (SS) activity after the CS. Modality-specific differences were found in the length of the post-CS pause, the presence of a post-pause rebound, the effect of pre-CS SS firing rate on pause duration and in the frequency and regularity of post-pause SS discharge. We concluded that these differences arouse from the location of the PC within the climbing fiber (CF) sagittal strip and from the differential activation of the inhibitory interneurons. We propose that modification of SS activity following a CS represents a possible means of information transmission by the CF system.