Motor skill learning induces changes in white matter microstructure and myelination.

Area of Science:

• Neuroscience
• Motor Learning
• Neuroplasticity

Background:

• Motor skill learning induces plasticity in the rodent motor cortex.
• Human neuroimaging suggests white matter (WM) structural changes occur during visuomotor learning, but the biological basis is unclear.

Purpose of the Study:

• To investigate the influence of motor skill learning on WM structure within the sensorimotor cortex.
• To determine if learning-related WM changes correlate with learning rate.

Main Methods:

• Diffusion MRI fractional anisotropy (FA) and quantitative immunohistochemistry were used to assess WM structure in rats.
• Seventy-two rats were divided into skilled reaching, unskilled reaching, and control groups for 11 days of training.

Main Results:

• Skilled reaching increased FA in WM subjacent to the sensorimotor cortex contralateral to the trained limb.
• FA in widespread WM regions correlated with learning rate in the skilled group.
• Immunohistochemistry revealed increased myelin staining in the trained hemisphere's WM, correlating with learning rate.

Conclusions:

• Novel motor skill learning induces structural changes in task-relevant WM pathways.
• These WM changes may reflect learning-related increases in myelination.