Evoked responses of the cat's visual cortex to optic tract stimulation at temperatures between 39° and 15°C

Abstract The survival time of the evoked response of the visual cortex after electrical stimulation of the optic tract near the chiasma was measured in the isolated cat's head after acute and complete ischaemia at different temperatures. It increased with decreasing temperatures, to reach a maximum at about 4 1 2 min. between 23° and 28°C. Further decrease in temperature shortened the survival time, which was 2 min. at 16°C. During ischaemia the amplitude of the evoked response temporarily increased to a maximum. The period from the onset of ischaemia to the point of maximum amplitude of the evoked response increased continuously with decreasing temperatures.