Abstract
Physiological characteristics of first order horizontal canal neurons, especially in their spontaneous activity, were studied in 11 unpigmented guinea pigs. Ninety-three single neurons were recorded and their inter-spike intervals and regularity of the resting discharge were analyzed. Mean inter-spike intervals was 40.5 msec with a range of 11 to 227 msec.
The neurons were classified into three groups according to their regularity of resting dis- charge which was determined by coefficient of variation (CV). Fourty neurons (43.0%) showed regular type of resting discharge and their mean inter-spike intervals was 20.2 msec. Thirty-six (38.7%) neurons exhibited intermediate type and had 32.2 msec mean inter-spike intervals. Remaining seventeen neurons (18.7%) were classified as irregular type and showed mean interspike interval of 95.5 msec.
The basic physiological characteristics of spontaneous activity in unpigmented guinea pigs were same as pigmented guinea pigs reported by Curthoys (1982), but the mean inter-spike intervals in unpigmented guinea pigs was clearly greater than that of pigmented guinea pigs.
