OBSERVATION ON THE PHOTIC DRIVING IN THE CORTEX AND SUBCORTEX OF THE CAT

S ummary 1) The drivings caused by photic stimulation were observed in various parts of the cortex and the subcortex of non‐anesthetized cats with the use of no restraint. 2) The lateral geniculate nucleus gave perfect driving at 3–30 c/s flicker rates, responded with spikes and sharp waves. 3) Drivings were recorded at the nucleus centralis lateralis, nucleus reticularis and nucleus lateralis‐posterior of the thalamus. At the nucleus centralis lateralis and the nucleus reticularis, drivings in form of waves were observed at about 3–30 c/s flicker rates, but at the nucleus lateralis posterior drivings were provoked as sharp waves. In these nuclei of the thalamus, regular second‐harmonic responses were sometimes recorded constantly at about 18–28 c/s flicker rates, and the spindle‐like burst and the waxing and waning of driving were often recorded at certain flicker rates. 4) At the mesencephalic reticular formation, drivings were recorded in the shape of more simple waves. 5) Drivings were provoked both at the posterior and at the ventromedialis of the hypothalamus but never at its anterior. 6) At the dorsal part of the hippocampus, drivings were caused in general at somewhat higher frequency than 8–30 c/s flicker rates. 7) Drivings in the cortex were investigated at the gyrus sigmoideus posterior, the gyrus lateralis, the gyrus suprasylvius medius and the gyrus posterolateralis, and each characteristic of driving in the respective areas was observed. 8) From the above results. the methodological possibility in psychopharmacological study with utilization of photic driving was referred.