Latent defect in monocular optokinetic nystagmus after neonatal removal of the lateral suprasylvian area in the cat.
Three kittens underwent unilateral removal of the lateral suprasylvian area of cortex at the age of 1 month. After normal rearing for two years, their monocular optokinetic nystagmus was studied. During the experiment one eye was 'seeing' the optokinetic stimulus, but the other eye was 'covered'; by implanting scleral coils on both eyes, we measured movements not only in the 'seeing' eye, but also in the 'covered' eye. The stimulus was moved at a velocity between 1 and 40 degrees/s. Additionally, movements of the both eyes were simultaneously recorded in a normal cat. The previous results on movements of both eyes in normal cats which had been derived from the recordings by one coil (Vision Res., 26: 1311-1314, 1986) were confirmed by this experiment and were compared with the results of the lesioned cats. The gains (slow phase velocity/stimulus velocity) of the 'seeing' eye were not significantly different from the normal values. However, the gains of the 'covered' eye were significantly higher than the normal values when the stimulus was presented in the temporonasal direction, at the velocities between 1 and 40 degrees/s to the eye ipsilateral to the lesion and at the velocity of 40 degrees/s to the eye contralateral to the lesion; in the other conditions of stimulation the gains were not significantly different from the normal values.
Hamada
T
T
Laboratoire Neuropsychologie Experimentale, INSERM Unité 94, Bron, France.
Flandrin
J M
JM
Furuya
N
N
D000818:Animals; D000831:Animals, Newborn; D002415:Cats; D009473:Neuronal Plasticity; D009759:Nystagmus, Pathologic / Q000503:physiopathology*; D010775:Photic Stimulation; D013702:Temporal Lobe / Q000502:physiology*; D014795:Visual Pathways / Q000502:physiology*