Motor system plasticity after unilateral injury in the developing brain

Area of Science:

• Neuroscience
• Developmental Biology
• Motor Control

Background:

• Motor skills rely on corticospinal tract (CST) and brainstem pathways synapsing on spinal cord neurons.
• Development of motor circuits involves genetic mechanisms and activity-dependent synaptic refinement.
• Understanding these developmental processes is key to addressing motor impairments, especially after injury.

Purpose of the Study:

• To review key activity-dependent developmental mechanisms in the motor system.
• To explore how these mechanisms establish connections for skilled movement.
• To understand their role in motor impairments and plasticity following corticospinal system injury.

Main Methods:

• Review of literature focusing on four key activity-dependent developmental mechanisms.
• Analysis of synaptic competition between bilateral CSTs.
• Examination of CST interactions with spinal neurons and sensory fibers.
• Investigation of corticospinal tract interactions with the rubrospinal tract.

Main Results:

• The corticospinal motor system actively oversees the development of its subcortical targets.
• Synaptic competition and trophic-like interactions are critical in this oversight.
• These mechanisms are fundamental for establishing proper connections for skilled motor control.

Conclusions:

• Activity-dependent mechanisms, including synaptic competition, are vital for motor system development.
• The corticospinal system's 'oversight' role has significant implications for motor recovery.
• Findings are particularly relevant for understanding motor impairments after perinatal cortical stroke.