Large-scale plasticity of the human motor cortex

Area of Science:

• Neuroscience
• Neuroplasticity
• Motor Cortex Function

Background:

• The adult primate brain exhibits remarkable plasticity, enabling rapid modification of cortical receptive fields and motor output modules.
• Altered synaptic input can drive these adaptive changes in brain organization.

Purpose of the Study:

• To investigate the extent of brain reorganization in response to slowly developing lesions in the motor cortex.
• To map regional cerebral blood flow changes during voluntary finger movements in patients with hand area motor cortex tumors.

Main Methods:

• Positron emission tomography (PET) was employed to measure regional cerebral blood flow.
• Functional activations were mapped during voluntary finger movements in patients with motor cortex tumors.

Main Results:

• All patients demonstrated cerebral blood flow activations exclusively outside the tumor site.
• Activations were observed to shift significantly (9-43 mm) from the affected area.
• These shifts extended along the mediolateral body representation of the motor cortex and into premotor or parietal somatosensory areas.

Conclusions:

• Slowly developing lesions in the motor cortex can induce large-scale brain reorganization.
• This reorganization is not limited to the immediate somatotopic representation within the motor cortex.
• Evidence supports extensive neuroplasticity beyond the primary motor cortex in response to damage.