Electrophysiological evidence for vestibular activation of the guinea pig hippocampus

Vestibular information modulates hippocampal activity for spatial processin g and place cell firing. However, evidence of a purely vestibular stimulus modulating hippocampal activity is confounded as most studies use stimuli c ontaining somatasensory and visual components. In the present study, high-f requency electrical stimulation of specific vestibular sensory regions of t he right labyrinth in anaesthetized guinea pigs induced an evoked field pot ential in the hippocampal formation bilaterally with a latency of about 40 ms following stimulation onset. Field potentials localized in the hippocamp al formation occurred with stimulus current parameters that were too small to produce eye movements. This provides direct electrophysiological evidenc e of vestibular input to the hippocampus. NeuroReport 11:1443-1447 (C) 2000 Lippincott Williams & Wilkins.