Electrophysiological evidence for afferent nerve fibers in human ventral roots.
This study was designed to test the hypothesis that ventral roots in humans contain afferent nerve fibers. We made direct electrophysiological recordings of compound nerve action potentials in dorsal and ventral roots in children undergoing selective dorsal rhizotomy for spastic cerebral palsy. We stimulated the saphenous or sural nerves, which are pure sensory nerves, with electrical stimuli while systematically recording from ventral and dorsal roots from L3 to S2. In addition to the dorsal root nerve action potentials which we expected, we found smaller compound nerve action potentials, which were clearly afferent, in the ventral roots. This confirms the limited amount of experimental evidence that ventral roots do contain some afferent nerve fibers. The functional significance of these observations is not yet clear.
Phillips
L H
LH
Department of Neurology, Box 394, University of Virginia, Charlottesville, Virginia 22908, USA. lhp3n@virginia.edu
Park
T S
TS
Shaffrey
M E
ME
Shaffrey
C L
CL
D000200:Action Potentials / Q000502:physiology; D002420:Cauda Equina / Q000166:cytology / Q000502:physiology; D002547:Cerebral Palsy / Q000503:physiopathology; D004558:Electric Stimulation; D006801:Humans; D009128:Muscle Spasticity / Q000503:physiopathology; D009431:Neural Conduction / Q000502:physiology*; D009475:Neurons, Afferent / Q000502:physiology*; D011446:Prospective Studies; D013126:Spinal Nerve Roots / Q000166:cytology* / Q000502:physiology*; D013497:Sural Nerve / Q000502:physiology