Cerebral potentials are not evoked by activation of Golgi tendon organ afferents in human abductor hallucis muscle.
The earliest components of the somatosensory evoked potentials (SSEP) are generated by excitation of the fastest low-threshold, thick myelinated group I afferents. Ib afferents belonging to this group innervate Golgi tendon organs and are excited almost selectively by a muscle twitch. Contraction of the abductor hallucis muscle was evoked by intramuscularly placed teflon insulated needle electrodes in ten healthy volunteers. We failed to demonstrate any cortical activity (over Cz' vs. Fz) following isolated muscle contractions. Our results do not point to a significant projection of group Ib afferents to the human somatosensory cortex at least with the small numbers of fibers activated by intramuscular stimulation of abductor hallucis muscle.
Ellrich
J
J
Department of Neurology, Johannes Gutenberg University, Mainz, Germany. ellrich@physiologie1.uni.erlangen.de
Hopf
H C
HC
D000328:Adult; D000344:Afferent Pathways / Q000502:physiology; D000368:Aged; D004558:Electric Stimulation; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D008297:Male; D008465:Mechanoreceptors / Q000503:physiopathology*; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000294:innervation*; D009413:Nerve Fibers, Myelinated / Q000502:physiology*; D013003:Somatosensory Cortex / Q000502:physiology; D013979:Tibial Nerve / Q000502:physiology; D014034:Toes / Q000294:innervation