Developmental timecourse of aptitude for motor skill learning in mouse

Area of Science:

• Neuroscience
• Developmental Biology
• Motor Control

Background:

• Motor skill acquisition relies on neural plasticity in the primary motor cortex (M1).
• The brain's capacity for plasticity changes across development, particularly in sensory areas.
• Understanding the developmental trajectory of motor learning is crucial for identifying optimal learning periods.

Purpose of the Study:

• To investigate the developmental trajectory of motor learning in mice.
• To determine how motor learning aptitude varies with age.
• To explore the role of the primary motor cortex (M1) in age-dependent motor learning.

Main Methods:

• Mice of both sexes (postnatal days 20-120) were trained on an accelerating rotarod.
• Paw position, time to fall, and gait patterns were quantified.
• Primary motor cortex (M1) function was inhibited pharmacologically to assess its necessity.

Main Results:

• All age groups improved performance after training, but the P30-60 group showed the most rapid initial improvement, suggesting heightened plasticity.
• Pharmacological inactivation of M1 abolished learning, confirming its essential role.
• Learners shifted gait from hopping to walking, with forelimbs adjusting earlier than hindlimbs, indicating potential forelimb plasticity advantage.

Conclusions:

• Mouse motor learning exhibits a distinct developmental trajectory with a potential sensitive period for plasticity.
• The primary motor cortex (M1) is critical for motor learning across development.
• Gait adaptation, particularly in forelimbs, provides nuanced insights into motor skill acquisition and plasticity.