Somatosensory evoked potentials following voluntary movement during upper arm compression.
We examined the modulation of somatosensory evoked potentials (SEPs) during upper arm compression and following voluntary movement during upper arm compression. Most SEPs were significantly decreased, although some SEPs showed a slight, non-significant diminution. SEPs are mediated not only by myelinated fibers but also by mixed nerves and afferents from cutaneous, joints, and deep tissues, these being dependent upon the dorsal column-medical lemniscal system. Therefore, most of the diminution in SEPs found here may have been due to afferent occlusion from muscle, cutaneous, joints, and deep tissues, since normal SEPs are selectively modulated, corresponding to motor or mental tasks, regardless of whether gating is centrifugal or centripetal. In addition, the present experiments showed that all the SEPs at FZ, C3' and CZ were significantly decreased following voluntary movement at a pressure 25%-30% higher than the subject's systolic blood pressure. Comparing SEPs during upper arm compression and those following voluntary movement during upper arm compression at these pressures, we found that the SEPs at C3' were significantly diminished following voluntary movement during upper arm compression, with other SEPs showing slight, non-significant attenuation. In conclusion, it is possible that the diminution in SEPs following voluntary movement could be responsible for sensory inputs, however, when sensory inputs are present, centrifugal modulation would also be responsible for this diminution.
Nishihira
Y
Y
Division of Physiology, Institute of Health and Sport Sciences, University of Tsukuba, Ibaraki, Japan.
Araki
H
H
Funase
K
K
Imanaka
K
K
Suzuki
J
J
Takemiya
T
T
D000328:Adult; D000344:Afferent Pathways / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D006801:Humans; D008297:Male; D008465:Mechanoreceptors / Q000502:physiology*; D008475:Median Nerve / Q000502:physiology; D009043:Motor Activity / Q000502:physiology*; D018482:Muscle, Skeletal / Q000294:innervation*; D009413:Nerve Fibers, Myelinated / Q000502:physiology; D010525:Peripheral Nerves / Q000502:physiology*; D011312:Pressure; D012867:Skin / Q000294:innervation; D013003:Somatosensory Cortex / Q000502:physiology