One hand clapping: lateralization of motor control.

Area of Science:

• Neuroscience
• Motor Control
• Developmental Neuroscience

Background:

• Lateralization of motor control is essential for complex activities like locomotion and bimanual tasks.
• Understanding the neuroanatomical and pathophysiological basis of lateralized motor output is critical.

Purpose of the Study:

• To discuss the neuroanatomical substrates and pathophysiological underpinnings of lateralized motor outputs.
• To explore recent breakthroughs from studying congenital mirror movements in humans and hopping gait in rodents.

Main Methods:

• Comparative analysis of human patients with congenital mirror movements.
• Study of model rodents exhibiting abnormal hopping gait.
• Investigation of interhemispheric connectivity, corticospinal projections, and spinal cord interneuron trajectories.

Main Results:

• Mirror movements are linked to altered interhemispheric connectivity and corticospinal projections.
• Hopping gait in rodents is associated with abnormal spinal cord interneuron trajectories.
• Both conditions highlight the importance of commissural axon guidance for asymmetric movement production.

Conclusions:

• Lateralized motor output relies on lateralized brain/spinal cord activation via midline inhibition.
• Unilateral transmission of neural activation is key for producing asymmetric movements.
• Similar principles of contralateral silencing and unilateral transmission apply to both brain and spinal cord mechanisms.