H-Reflex Up-Conditioning Encourages Recovery of EMG Activity and H-Reflexes after Sciatic Nerve Transection and Repair in Rats

The Journal of Neuroscience, 2010 · DOI: 10.1523/JNEUROSCI.4578-10.2010 · Published: December 1, 2010

Simple Explanation

This study investigates whether operant conditioning of the H-reflex, an electrical analog of the spinal stretch reflex, can improve functional outcomes after peripheral nerve injury. Rats underwent sciatic nerve transection and repair, followed by either continued control data collection or H-reflex up-conditioning for 120 days. The results suggest that H-reflex up-conditioning may enhance recovery by strengthening primary afferent reinnervation of motoneurons.

Study Duration

120 d

Participants

13 young male Sprague Dawley rats

Evidence Level

Level II: Animal Study

Key Findings

1
SOL (and probably TA) background EMG activity recovered faster in TU rats than in TC rats.
2
The final recovered SOL H-reflex was significantly larger in TU than in TC rats.
3
VGLUT1 terminals were significantly more numerous on SOL motoneurons of TU than TC rats, suggesting stronger primary afferent reinnervation.

Research Summary

The study assessed the impact of soleus (SOL) H-reflex up-conditioning on the recovery of SOL and tibialis anterior (TA) EMG activity and reflexes following sciatic nerve transection and repair in rats. H-reflex up-conditioning accelerated the recovery of background EMG activity in both SOL and TA muscles and increased the final size of the H-reflex. Anatomical analysis revealed a higher number of VGLUT1-positive terminals on SOL motoneurons in up-conditioned rats, suggesting enhanced primary afferent reinnervation.

Practical Implications

Therapeutic Potential

H-reflex up-conditioning may be a useful tool for improving functional recovery after peripheral nerve injuries.

Rehabilitation Strategies

Operant conditioning of spinal reflexes could be incorporated into rehabilitation programs to enhance motor recovery.

Spinal Cord Plasticity

The study highlights the potential for spinal cord plasticity to be harnessed for therapeutic benefit.

Study Limitations

1
The precise mechanisms responsible for the functional and anatomical effects remain uncertain.
2
The study only examined the effects of H-reflex up-conditioning on SOL and TA muscles.
3
Further research is needed to determine whether the reward contingency was responsible for the effects.

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