REFLEX EPILEPSY IN THE PAPIO-PAPIO BABOON, PARTICULARLY PHOTOSENSITIVE EPILEPSY

Papio-papio baboons may present two types of reflex paroxysmal manifes tations:Myoclonia and generalized seizures are induced by intermittent light stimulation in predisposed animals; this photosensitive epileps y resembles that observed in some human patients; it involves mainly t he cerebral cortex during myoclonia which ave accompanied by EEG parox ysmal discharges, and the mesencephalic reticular formation during sei zures; Myoclonia of a different type, never accompanied by EEG paroxys mal discharged and never evolving into seizures, may occur during move ment or agitation of predisposed animals; these myoclonia are consider ed ''non-epileptic'' since they do not involve the cerebral cortex but probably the lower brain stem; they resemble that observed in startle disease or in some human degenerative disorders. The paper demonstrat es that these manifestations constitute two different entities with cl inical and electrophysiological characteristics as well as pharmacolog ical reactivities completely different one from the other, Their ''epi leptic'' or ''non-epileptic'' nature is discussed.