Spreading depression and evoked potentials recorded in the somatosensory cortex of the rat

Abstract

Cortical spreading depression (CSD) is associated with changes in the caliber of surface blood vessels; others have described it as a phenomenon which arises spontaneously and repetitively following acute cortical injury in animals, including both focal ischemia and trauma, while yet other researchers consider it to be an electrophysiological substrate of migraine aura, which may trigger headache. Our group is involved in research into both migraine and ischemia-induced pathophysiological states. It therefore appeared reasonable to include the study of CSD in the methodological repertoire utilized in our laboratory. We introduced two models of CSD induction: CSD evoked during continuous topical KCl application and CSD induced through a single KCl microinjection into the cortical tissue. This paper describes details of these two methods and of basic parameters of CSDs.