Visually-evoked potentials elicited by a light-emitting diode chronically implanted in the frontal sinus of the freely moving cat.

Visually-evoked potentials (VEPs) were obtained with a small yellow light-emitting diode (LED), chronically implanted in the frontal sinus of the cat. The VEPs obtained in scotopic conditions through the LED have a similar morphology to those obtained with a stroboscopic flash. A noticeable delay was observed in LED wave latencies versus flash values. Analysis of wave intervals indicated a long-lasting generation of LED VEPs primary components. Secondary responses have a similar pattern with both modalities of stimulation. Implanted LEDs can be used as a reliable method to obtain VEPs and especially in those behavioural or pathological conditions in which variations exist in the constancy of the ocular media.