Abstract
Injuries to spinal ventral roots may induce plastic changes in adjacent segmental reflex pathways. Earlier studies in the cat have demonstrated that a partial loss of target motoneurons, following a ventral root avulsion injury, induces a compensatory enhancement of monosynaptic reflexes in adjacent segments. Here, we studied electrophysiologically the effects of a primarily non-lethal motoneuron injury of lumbosacral ventral roots on monosynaptic reflexes in adjacent intact motoneurons in the adult cat. A unilateral L7 or a combined L7 and S1 ventral root transection was first performed. We next recorded bilaterally monosynaptic reflexes from the L6 and S1 ventral roots while stimulating the bilateral L6, L7 and S1 dorsal roots at 6 and 12 weeks postoperatively. We demonstrated a prominent strengthening of monosynaptic reflexes in the immediately adjacent spinal cord segments. The reflexes had almost doubled in size at 6 and 12 weeks postoperatively. Possible mechanisms and factors contributing to the reflex enhancement are discussed.
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Acknowledgements
LAH is supported by grants from NIH (NS042719), State of California—The Roman Reed Bill, and The Paralysis Project of America. JOK is supported by grants from the Swedish Medical Research Council (project no. 02886), the Gunvor and Josef Anér’s Foundation, the K.O. Hansson Fund and Umeå University.
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Havton, L.A., Kellerth, JO. Plasticity of lumbosacral monosynaptic reflexes after a ventral root transection injury in the adult cat. Exp Brain Res 155, 111–114 (2004). https://doi.org/10.1007/s00221-003-1802-0
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DOI: https://doi.org/10.1007/s00221-003-1802-0