Electrophysiological analysis of the vestibulospinal reflex pathway of rabbit. I. Classification of tract cells

• DOI: 10.1007/bf00234863
• Publication Date: 2004-09-08T06:33:08Z
• Authors: T. Akaike; V.V. Fanardjian; M. Ito; M. Kumada; H. Nakajima
• Keywords: Neurons; 05 social sciences; Neural Conduction; Vestibular Nuclei; Vestibulocochlear Nerve; Electric Stimulation; Electrophysiology; Spinal Cord; Reflex; Animals; 0501 psychology and cognitive sciences; Rabbits; Microelectrodes

In anaesthetized rabbits, the medulla was surveyed with recording microelectrodes to identify different types of vestibulospinal tract neurones. Field potentials, unitary extracellular spikes and intracellular potentials were recorded during antidromic stimulation at C1 and C6 segments and during orthodromic stimulation through VIIIth nerve. The lateral and medial vestibulospinal tracts (LVST and MVST) were stimulated discriminately with the method developed in Appendix. On the basis of different axonal courses and conduction velocities, three major groups were distinguished for those cells which were activated monosynaptically by the primary vestibular afferents; 1. fast conducting LVST; 2. fast conducting MVST; and 3. slowly conducting MVST. Three other groups were discriminated for those cells which received only a polysynaptic or no action from primary vestibular afferents. These were; 4. fast conducting LVST; 5. slowly conducting LVST and 6. slowly conducting MVST. All of these six types of VST cells were represented within Deiters' nucleus. Only a relatively small number of MVST cells were found in the medial vestibular nucleus.