Temperature reactions of the rat cerebral cortex and distant effects of an experimentally induced excitatory focus

The method of dynamic thermovision was used in white rats to investigate the distant reactions of the cerebral cortex arising during local chemical perturbation (2% KCl). In addition to the earlier-described temperature wave of propagating depression (T waves), local areas of warming (by 0.2–0.3°) symmetrical to the site of stimulation were found in the opposite hemisphere. Latent excitation foci during local chemical action were found on the dynamic thermal maps of the brain surface in regions remote from the stimulation site in the same or contralateral hemisphere. A change in the site of T-wave origination and the typical sequence of its propagation through the cortex could be observed when two potassium foci were created, as well as the development of foci of prolonged temperature oscillations at the site of encounter of two T waves. On the basis of the obtained data several questions are discussed concerning the forms and mechanisms of distant effects in the CNS.