Reproduction of the 3 per Second Spike and Wave EEG Pattern by Snbcortical Electrical Stimulation in Cats

Summary. 1. Cortical 3 per second spike and wave activity — resembling the typical EEG potentials of petit mal in man — has been elicited by subcortical electrical stimulation in cats. On stimulation of medial thalamic structures the results in many respects confirm those of J asper and D roogleever ‐F ortuyn (1947). 2. The conditions for obtaining cortical “(recruiting responses)” (dempsey and M orison 1942) and spike and wave responses do not seem identical. 3. It has not been possible to establish the existence of a definable anatomical or functional anatomical subcortical system — consistent with any known such entity — which, on electrical stimulation, will produce a specific form of bilaterally symmetrical 3 per second spike and wave potentials with a general cortical distribution. 4. The results are not consistent with the pace‐maker theory which presumes a brain stem mechanism driving a passive cortex during the petit mal seizure. 5. It is emphasized that the reticular system of the brain stem still appears to be the only functional entity known, capable of the wide‐spread influence upon the cortex which is required to explain the generalized disturbance of the EEG during a petit mal seizure.