Abstract
The interaction between the fastigial and the Deiters' nuclei may be important substrates for adaptive postural control. To understand information processing through the two nuclei, we investigated effects of vestibular stimulation on fastigial nucleus (FN) neurons with their axons projecting to the lateral vestibular nucleus (LVN), and compared their response characteristics with those of LVN neurons. In decerebrate, immobilized Wistar rats, fastigial neurons were searched for by antidromic stimulation of the lateral vestibular nucleus, which was identified by field potential evoked from the lower thoracic spinal cord. Vestibular stimulation was performed by tapping of the stereotaxic apparatus in which the animals were fixed. For each neuron, tapping was applied to various directions, including fore-, back-, left-, right-, up-, and down-ward directions, and spatial properties of responses were determined.FN neurons responded to tapping of several directions with phasic bursts, of which the shortest latencies were distributed between 3-13 msec. Responding neurons were found mainly in the rostral part of the nucleus. Among FN neurons antidromically excited from the LVN, about half of the cells were responsive to vestibular stimulation. We supposed that these neurons may contribute to adaptive postural control. [Jpn J Physiol 55 Suppl:S175 (2005)]
