Long-last-ing reversible changes in the reflex responses of chronic spinal cats to touch, heat and cold.

Abstract

REPEATED cooling of one arm brings about a reduced rise of arterial pressure in man and a lessened awareness of cold pain1. It has been assumed that these modifications of response occur at the higher levels of the nervous system. Conditioned responses linking two different stimuli have, however, been reported in chronic spinal frogs2, dogs and cats, but diminution of the reflex reactions to a single type of stimulus—habituation—has rarely been examined in spinal animals3,4. Yet chronic spinal section offers a simple preparation for examination of the slow changes in reflex responses.