Spontaneous activity of first-order horizontal canal neurons in the guinea pig

The spontaneous activity of the primary horizontal canal neurons was investigated in 12 alert albino guinea pigs. Seventy-one neurons were recorded for analyzing spontaneous activity. These neurons had an average resting rate of 46.6 +/- 20.9 spikes/sec and a range of 2.2 to 113.6 spikes/sec. This was significantly higher than previously reported data recorded from anesthetized guinea pigs. The neurons were classified into three groups from values of coefficient of variation; regular, intermediate, and irregular firing units. Of the 71 units measured, 42.3% were regular, 42.3% were intermediate, and 15.4% were irregular discharge units. The incidence of the irregular units was slightly lower than that in the anesthetized animals. The difference in resting activity of the primary neurons with or without general anesthesia is discussed.