Asymmetry in pupillary light reactions in experimental baso-temporal seizures

Abstract

A study of pupillary light reflexes during and after seizures in the case of two distinct types of experimental focal epilepsy of the temporal lobe in cats, revealed asymmetries in the pupillary reactions to light. At the onset of each seizure, pupillary dilation occurred in either preparation with eventual fixation of one pupil in light attacks, and of both pupils in stronger seizures. At the height of the pupillary dilatation constrictive effect could still be elicited by illumination of either pupil until a stage was reached when illumination of one pupil elicited no response, either direct or consensual, whereas illumination of the other pupil elicited both of these responses. In the hippocampal preparations it was the contralateral, whereas in most of the amygdaloid preparations it was the ipsilateral pupil which was first to show such cessation of responses to light. At the end of the seizure the amygdaloid preparations showed a characteristic prolonged postictal paralysis of pupillary responses. In most preparations, reactivity first returned to the contralateral pupil which regained both direct and indirect responses prior to the ipsilateral pupil.