Locomotion engages context-dependent motor strategies for head stabilization in primates

Area of Science:

• Neuroscience
• Motor Control
• Biomechanics

Background:

• Flexible motor control is key for navigating dynamic environments.
• Understanding how neural and muscular activation patterns adapt to context is crucial but not well understood.

Purpose of the Study:

• To investigate the flexibility of motor coordination during locomotion under varying conditions.
• To characterize how head and body kinematics and muscle activity change during treadmill and overground walking, with and without arousal.

Main Methods:

• Recorded head and body kinematics and muscle activity in rhesus monkeys.
• Analyzed data using dimensionality reduction during treadmill walking at different speeds and overground walking with varied autonomic arousal.
• Correlated pupil size with muscle recruitment patterns.

Main Results:

• Treadmill walking showed a stable muscle activation structure that scaled with speed, indicating flexible scaling.
• Overground walking induced greater muscle engagement and organizational changes compared to treadmill walking.
• Elevated arousal during overground walking maintained structural muscle recruitment patterns, with larger pupils linked to stronger activation.

Conclusions:

• The brain dynamically adapts motor coordination to environmental context, even for automatic behaviors like walking.
• Motor control strategies are not stereotyped but are flexibly reorganized to meet task demands.
• Future research should examine motor control strategies across a diverse range of conditions to fully understand adaptability.