Abstract
1. Glass micropipettes were inserted into the oculomotor nucleus of the cat and electrical activities and properties of the neurons were studied with intracellular recordings.
2. The properties of ocular motoneurons were, in many respects, alike to those of lumbar spinal motoneurons. However, when compared with the latters, several characteristics of ocular motoneurons were noted; rather smaller time constant, shorter duration of after-hyperpolarization, lack or scarcity of collateral inhibition, much more frequent rates of tonic and phasic discharges and so on.
3. The local reflex activity in the oculomotor system was scarcely observed, but a few cases were encountered that seemed to be alike to those of proprioceptive responses in the spinal motor system.
4. Synaptic potentials in ocular motoneurons due to the VIIIth nerve stimulations were visualized by the intracellular recording, and their relations with focal potentials in the oculomotor nucleus and with discharge outflows to the IIIrd nerve, elicited by the same stimulations, were examined in concern with the vestibulo-ocular reflex.
