Exercise training improves motor skill learning via selective activation of mTOR

Area of Science:

• Neuroscience
• Molecular Biology
• Exercise Physiology

Background:

• Physical exercise is known to benefit cognitive functions like learning and memory.
• However, the precise molecular mechanisms underlying these benefits, particularly in vivo, remain largely unexplored.

Purpose of the Study:

• To investigate the in vivo molecular mechanisms by which physical exercise enhances learning and memory.
• To elucidate the role of the mechanistic target of rapamycin (mTOR) pathway in exercise-induced neural adaptations.

Main Methods:

• Chronic treadmill exercise was implemented in a mouse model.
• Ex vivo and in vivo electrophysiological recordings were performed.
• Oligodendrogenesis, axonal myelination, and dendritic spine formation were assessed.
• The activation of the mTOR pathway was specifically examined in the motor cortex.

Main Results:

• Chronic treadmill exercise activated the mTOR pathway in the mouse motor cortex.
• mTOR activation was associated with potentiated postsynaptic excitation and enhanced neuronal activity in layer 5 pyramidal neurons.
• Exercise led to increased oligodendrogenesis, axonal myelination, and dendritic spine formation.
• These molecular changes correlated with improved motor learning.

Conclusions:

• Exercise-induced mTOR pathway activation is a key mechanism underlying enhanced neuronal function and plasticity.
• The mTOR pathway mediates exercise-induced spinogenesis, neuronal activation, and axonal myelination, which collectively contribute to improved motor learning.
• These findings provide a molecular basis for understanding neural network adaptations to exercise and support exercise as an intervention for cognitive deficits.