Changes in the visual evoked potentials with different photic conditions in guinea pigs.
Visual evoked potential (VEP) was studied in five adult male guinea pigs weighing 350-750 g. VEPs were recorded with chronically implanted electrodes. Photic stimulation was presented in the following order: binocular, left eye, right eye, and screened binocular. The averages of the responses were made from 140 samples. When a single eye was exposed to photic stimulation, the ipsilateral VEP was different from the contralateral VEP; the peaks N140 and P200 disappeared, and the peak latencies of N75 and P100 were significantly (P less than 0.05) longer than those in the contralateral hemisphere. Peak-to-peak amplitude N40-P55 in the ipsilateral VEP was significantly (P less than 0.05) lower than that in the contralateral VEP. The contralateral VEP by monocular stimulation was generally indistinguishable from the response to binocular stimulation. As described above, when only a single eye was exposed to flashes, the ipsilateral dural VEP was different from the contralateral dural VEP.
Suzuki
M
M
Department of Veterinary Physiology, Faculty of Agriculture, Tottori University, Japan.
Sitizyo
K
K
Takeuchi
T
T
Saito
T
T
D000818:Animals; D004566:Electrodes; D005074:Evoked Potentials, Visual; D006168:Guinea Pigs / Q000502:physiology*; D008297:Male; D010775:Photic Stimulation