INFLUENCE OF HIGH OXYGEN PRESSURE ON ELECTRICAL ACTIVITY OF BRAIN

In the present study the origin and site of hyperbaric oxygen convulsions was investigated. The electrical activity of intact rabbit brain in curarized animals was studied with the help of electrodes implanted in cortical and subcortical areas and the EEG was continuously recorded before, during and after seizures. Early abnormal cerebral activity, consisting of runs of slow waves or bursts of sharp waves, was most frequently recorded from cortical leads. There was no constant focus in any particular cortical area examined, neither was their appearance simultaneous in several structures. In half of the animals the early abnormal activity developed into generalized discharge. Occasionally, early changes were first recorded in subcortical areas, spreading to cortex and other adjacent subcortical areas. In conformity with previous experimental work carried out by other investigators our results show that no brain structure plays a particular role in the genesis and development of hyperbaric oxygen seizures; neither could any area be demonstrated as particularly sensitive in their production. Our studies appear to imply that, in the intact brain of curarized rabbits, these seizures have a random origin, or else develop simultaneously in many brain structures. © 1969.