Transmission times from cutaneous and mixed nerves of lower limbs.
In each of 10 normal subjects, P28 and N31 far-field components as well as the cortical N37 and P40 waves were identified for both Sural (SN) and Posterior Tibial nerve (PTN) stimulation at the ankle. Peripheral conduction velocity along the popliteal fossa-L3 segment and spinal transmission velocity over the L3-Cv2 segment did not differ significantly for the two nerves. The average latencies of N37 and P40 to stimulation of PTN were 2.55 and 3.65 msec shorter than corresponding latencies from SN. If we consider the P28-N37 and P28-P40 intervals as central transmission times, only the former approaches upper limb CCT values closely enough to support the analogy between median nerve N20 and PTN N37. At the intracranial level, the P28-N37 inter-peak latency was significantly shorter for PTN than SN. The P28 component is generally attributed to lemniscal activity. Thus, the discrepancy in afferent transmission times from the leg's mixed and sensory nerves would appear to take place at a level that is supralemniscal but subcortical.
Amantini
A
A
Department of Neurological and Psychiatric Sciences, University of Florence, Italy.
Bartelli
M
M
de Scisciolo
G
G
Lombardi
M
M
Grippo
A
A
Pinto
F
F
D000328:Adult; D004558:Electric Stimulation; D005073:Evoked Potentials, Somatosensory; D005260:Female; D006801:Humans; D008297:Male; D009431:Neural Conduction; D011930:Reaction Time; D012535:Scalp / Q000502:physiology; D013127:Spinal Nerves / Q000502:physiology; D013497:Sural Nerve / Q000502:physiology*; D009435:Synaptic Transmission; D013979:Tibial Nerve / Q000502:physiology*