| Abstract: | Discharges of 184 motor units of the sartorius muscle functioning during cold tremor were investigated in acute experiments on anesthetized cats. Units whose discharges correlated with respiration cycles and units functionally independent of the rhythm of respiration were discovered. Discharges of both types of motor units possessed the same mean frequency (4–12 spikes/sec) and the same low variability of interspike intervals. Additional temperature stimulation of the vascular temperature receptors and changes in the frequency and depth of the respiratory excursions during cold tremor evoked identical responses in the two types of units. It is concluded that both types of motor units have similar thresholds and are of the slow, phasic type.O. V. Kuusinen State University, Petrozavodsk. Translated from Neirofiziologiya, Vol. 11, No. 4, pp. 355–361, July–August, 1979. |
