Eye movements evoked by electrical stimualtion of the brain in anesthetized fishes.

Abstract

Several eye movements were evoked by electrical stimulation of the brain in anesthetized sunfish and goldfish. Conjugate lateral rolling movements, similar to eye movements observed when an unoperated fish is rotated about its long axis, were evoked from the acoustico-lateral area of the medulla and the eminentia granularis and an adjacent medial portion of the cerebellum. Bilateral and unilateral backward rotations, similar to the eye movements observed when unoperated fish are rotated forward about the interpupillary axis, were evoked from the medial longitudinal fasciculus and areas related to the oculomotor nerve. Bilateral forward rotations, comparable to the eye movements resulting when unoperated fish are rotated backward about the interpupillary axis, were elicited by stimulation near the trochlear nerve roots in the valvula of the cerebellum; unilateral responses resulted from stimulation near the exiting trochlear nerves. Convergence was elicited by stimulation in the midline near the oculomotor complex and the medial longitudinal fasciculus while unilateral vergence responses were triggered by stimulation in the medial longitudinal fasciculus and areas lateral to the oculomotor nucleus. Conjugate eye movements in the horizontal plane were frequently evoked but were not studied in detail.