Responses of the inferior olive to peripheral stimuli and the spinal pathways involved

Electrical stimulation of mixed and cutaneous nerves of the hindleg of cats activated the medial and ventral accessory olives of the opposite side; small responses were also present in the same parts of the ipsilateral olivary complex. No responses were present following stimulation of nerves to muscle (hamstrings, nerves to gastrocnemius) or of cutaneous nerves of the foreleg. The main and constant component of the olivary potentials is a negative wave the duration and amplitude of which depends on the strength of the peripheral volley and particularly on the activation of the gamma-delta groups. It is likely that spino-olivary projections play some role in the general reaction to painful stimulation. By means of acute cord incisions it was established that spino-olivary fibers are mainly crossed with respect to the stimulated side and run in the ventral funiculus of the cord.