Neuronal origin of the transcorneal electrically evoked response in area 17 (primary visual cortex) of cats

We investigated how the neuronal activity of the cells in area 17 of cats evoked by transcorneal electrical stimuli is associated with the transcorneal electrically evoked response (EER). Neuronal firings were associated with the negative components of the EER, N1 (9 ms latency) and N2 (20 ms latency). Excitation of a longer latency was suppressed and periodic firings were rarely found. These findings indicate that the early negative components of the EER consist of the synaptic activities over the discharge thresholds of cortical cells, and also suggest that inhibition in the visual cortex may affect the EER.