Estimation of generator potentials in primary spindle endings evoked by brief tendon taps in man.
The ligamentum patellae in human subjects was tapped by a random triangular waveform, while single primary spindle afferent spikes were recorded from the femoral nerve. Cross-correlation between the primary spindle afferent spikes and the taps revealed a prominent peaked distribution of the discharge probability. The cross-correlograms showed that response time from the onsets of taps to the afferent spike was 7.5 +/- 0.6 msec in 6 units and that the width between the feet of the peaked distribution was 3.3 +/- 0.2 msec in 6 units. The width of the peak implies jitter of the response time of the primary spindle spikes which appear to correspond with the time-to-peak of generator potentials elicited by the taps in primary endings of muscle spindles. Integration of the peaked distribution showed a slow slope at the beginning and near the summit and a steep slope on the way. This curve is assumed to represent the rising phase of the generator potentials in primary spindle endings.
D000344:Afferent Pathways / Q000502:physiology; D005071:Evoked Potentials; D005267:Femoral Nerve / Q000502:physiology; D006801:Humans; D008465:Mechanoreceptors / Q000502:physiology*; D009045:Motor Endplate / Q000502:physiology; D009470:Muscle Spindles / Q000502:physiology; D010812:Physical Stimulation; D011930:Reaction Time / Q000502:physiology; D012026:Reflex, Stretch; D009435:Synaptic Transmission