Behavioral activities of axotomized abducens nucleus motoneurons in the alert cat

The activity of identified control and axotomized abducens motoneurons has been recorded during spontaneous eye movements in the alert cat. Axotomized motoneurons showed a quick fatigability during eye fixations not observed in controls. Discharge rate of axotomized motoneurons during on direction saccades was lower and shorter than in controls and started usually after the beginning of the saccade. Axotomized motoneurons could be antidromically invaded only in the presence of synaptic facilitation. Electrophysiological explanations for the behavior of axotomized motoneurons in the alert cat are discussed in the text.