The characteristics of the baseline spike activity of neurons in the superior vestibular nucleus of rats were studied after exposure to vibration for five, 10, and 15 days using a computerized method for recording and analyzing interspike intervals. The distributions of neurons in terms of their regularity, their dynamic types, and the modalities of their interspike interval histograms were assessed. In intact animals, the mean spike frequency was 14.0 +/- 1.4 Hz. Changes in the main measures were seen at different durations of exposure to vibration, along with a significant increase in the mean neuron spike frequency. The results demonstrate changes in the level of the functional state of neurons in the superior vestibular nucleus after exposure to vibration. The characteristics and significance of the results are discussed.