Vibration-induced inhibition of the early components of the tibial nerve somatosensory evoked potential is mediated at a spinal synapse.
OBJECTIVE
To investigate whether afferent-induced suppression of cortical somatosensory evoked potentials (SEPs) occurs at a spinal site along the transmission route of afferent signals from the tibial nerve to the primary somatosensory cortex.


METHODS
Evoked potentials were recorded at 4 points (sciatic nerve, L5, C1, and cortex) along the path of transmission following electrical stimulation of the tibial nerve in halothane-anesthetized cats. The amplitudes of evoked potentials sampled during vibration of quadriceps were compared to evoked potentials sampled without the vibration.


RESULTS
The spinal SEP recorded at C1 and the cortical SEP were both substantially reduced by patellar tendon vibration. The L5 spinal SEP and the sciatic nerve potential were unaffected. Vibration of quadriceps did not influence the latency of the evoked potentials.


CONCLUSIONS
These results indicate that afferent-induced suppression of the initial complex of the SEP can be mediated at a spinal synapse.
Misiaszek
J E
JE
Department of Occupational Therapy, 2-64 Corbett Hall, University of Alberta, Alberta T6G 2G4, Edmonton, Canada. john.misiaszek@ualberts.ca
Brooke
J D
JD
D000818:Animals; D002415:Cats; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D009433:Neural Inhibition / Q000502:physiology*; D010329:Patella; D012584:Sciatic Nerve / Q000502:physiology; D013003:Somatosensory Cortex / Q000502:physiology; D013116:Spinal Cord / Q000502:physiology*; D013569:Synapses / Q000502:physiology*; D013710:Tendons / Q000502:physiology; D013979:Tibial Nerve / Q000502:physiology*; D014732:Vibration