[Analysis of electrically evoked response (EER) in relation to the central visual pathway of the cat (2). Response characteristics of the lateral geniculate neurons].
To analyze the electrically evoked response (EER) in relation to the central visual pathway, the response characteristics of the lateral geniculate neurons (LGNs) of the EER in 35 anesthetized adult cats were studied. Responses of the LGNs showed interindividual variation of more than one log unit in terms of the stimulus threshold for electrical stimuli. As the stimulus intensity increased, the spikes with constant latencies were recorded, which showed bursts with much stronger stimuli. The latencies of the spikes were closely correlated with those of negative components of EER. The LGNs were divided into two major groups by the latency. The periodical and alternative excitation of these neurons contributed to form the first negative wave of EER. The latency of these two major groups of LGNs was reversed when the electrode polarity was changed. At higher stimulus intensities, the components with short latency became dominant and those with longer latency were suppressed. The above results suggested that the periodical excitation of LGNs and the formation of the prominent EER components may result from the interaction between on- and off-type retinal ganglion cells and amacrine cells. It was also suggested that the origins of the wavelets in negative waves of EER at strong stimuli are the bursts of the spikes of the visual cortex neurons.
Fukatsu
Y
Y
Eye Clinic, Toyota Memorial Hospital, Japan.
Miyake
Y
Y
Sugita
S
S
Watanabe
S
S
D000818:Animals; D002415:Cats; D004558:Electric Stimulation; D005071:Evoked Potentials; D005829:Geniculate Bodies / Q000502:physiology*; D009474:Neurons / Q000502:physiology; D010507:Periodicity; D011930:Reaction Time; D014795:Visual Pathways / Q000502:physiology*