Long-range plasticity between intact hemispheres after contralateral cervical nerve transfer in humans

Area of Science:

• Neuroscience
• Motor Cortex Plasticity
• Peripheral Nerve Injury

Background:

• Peripheral nerve injury typically causes functional reorganization within the same brain hemisphere.
• Interhemispheric cortical plasticity is increasingly recognized, particularly after direct brain damage.
• Long-range interhemispheric plasticity in response to peripheral nerve injury is less understood.

Purpose of the Study:

• To investigate long-range interhemispheric cortical plasticity in adults with brachial plexus avulsion injury (BPAI).
• To determine if contralateral cervical nerve transfer can reverse BPAI-induced intrahemispheric cortical reorganization.

Main Methods:

• Positron Emission Tomography (PET) scanning was used.
• The study included 8 adult male patients with BPAI who underwent contralateral C-7 nerve transfer.

Main Results:

• The right somatomotor cortices remained crucial for controlling the injured limb post-nerve transfer.
• This suggests the brain attempts to maintain control of the injured limb via its original cortical area.
• Findings align with previous animal study results on cortical reorganization.

Conclusions:

• Complex peripheral pathway changes can induce long-range interhemispheric cortical reorganization in the human motor cortex.
• The brain demonstrates plasticity by attempting to restore limb control to its original cortical representation.