Abstract:

Although some patients have successful peripheral nerve regeneration, a poor recovery of hand function often occurs after peripheral
nerve injury. It is believed that the capability of brain plasticity is crucial for the recovery of hand function. The supplementary motor area
may play a key role in brain remodeling after peripheral nerve injury. In this study, we explored the activation mode of the supplementary
motor area during a motor imagery task. We investigated the plasticity of the central nervous system after brachial plexus injury, using the
motor imagery task. Results from functional magnetic resonance imaging showed that after brachial plexus injury, the motor imagery task
for the affected limbs of the patients triggered no obvious activation of bilateral supplementary motor areas. This result indicates that it is
difficult to excite the supplementary motor areas of brachial plexus injury patients during a motor imagery task, thereby impacting brain
remodeling. Deactivation of the supplementary motor area is likely to be a serious problem for brachial plexus injury patients in terms of
preparing, initiating and executing certain movements, which may be partly responsible for the unsatisfactory clinical recovery of hand
function.

Key words: nerve regeneration, peripheral nerve injury, brachial plexus injury, neuronal plasticity, supplementary motor area, premotor area, magnetic resonance imaging, motor preparation, motor imagery, clinical restoration of hand function, cortical remodeling, block design, neural
regeneration