Reciprocal inhibition between seizures induced by intermittent light stimulation and premotor cortical stimulation in Senegalese baboons, Papio papio.

The temporal relationship between the degree of photosensitivity and the intensity of kindling stimulus response was examined in four Senegalese baboons, Papio papio, kindled at the premotor cortical area. When fully kindled, the intensity of photosensitivity diminished significantly in all the animals. With successive daily intermittent light stimulation, two animals showed partial recovery and the other two showed complete recovery to the prekindling level of photosensitivity. When premotor cortical kindling stimulation was subsequently reapplied, three-quarters of the animals failed to respond with kindled seizures and additional stimulations were necessary to reestablish kindled seizure. Two of these three animals also required increased stimulus intensity before the previously established generalized seizure threshold could be reinstated. The frontorolandic cortex is known as the most epileptogenic area in photosensitive Papio papio. In this species, spontaneous generalized convulsive seizures, intermittent light stimulation-induced seizures, and kindled generalized convulsive seizures are all known to share a common electroclinical phenomenology. The reciprocal inhibition observed in this study between generalized seizures induced by either intermittent light stimulation or by premotor cortical kindling stimulation further strengthens the possibility that they also share a common neuronal mechanism.