[Activity of axotomized motor neurons of the external oculomotor nucleus in the waking cat].

The spontaneous and the visual and vestibular induced activity of axotomized abducens motoneurons (ABD Mns) has been recorded in alert cats. Axotomy was carried out peripherally in the ocular orbit. ABD Mns were identified by their antidromic activation from the VIth nerve. Control Mns showed a clear relationship with eye position and velocity in the horizontal plane, whereas axotomized Mns showed a remarkable variability in their antidromic activation, a rapid fatigability during eye fixations and a decreased sensibility to eye velocity. Occasionally, axotomized Mns fired a short burst of activity before saccades in the off-direction. Functional involvements of described findings are discussed.