Neural Control Adaptation to Motor Noise Manipulation

Area of Science:

• Motor control
• Neuroscience
• Biomechanics

Background:

• Antagonistic muscle co-activation can mitigate movement variability caused by motor noise.
• Increased co-activation is observed in older adults, potentially as an adaptation to higher motor noise.
• This study investigates the nervous system's response to manipulated motor noise.

Purpose of the Study:

• To test if increased motor noise leads to greater antagonistic co-activation.
• To determine if reducing motor noise improves performance.
• To understand the role of co-activation in adapting to motor noise.

Main Methods:

• Manipulated motor noise in young subjects using a myoelectric virtual arm.
• Increased motor noise by altering the coefficient of variation (CV) of myoelectric signals.
• Decreased motor noise by smoothing myoelectric signals.

Main Results:

• Subjects increased antagonistic co-activation in response to increased motor noise, reducing performance decrements.
• Decreasing motor noise did not improve performance and did not alter co-activation levels.
• The filtering process for noise reduction may introduce delays and attenuate muscle activity, hindering performance benefits.

Conclusions:

• The nervous system adapts to increased motor noise by enhancing antagonistic co-activation, thereby maintaining motor performance.
• Reduced motor noise did not benefit performance, possibly due to filtering artifacts.
• Elevated co-activation in older adults and patient populations may be an adaptation to increased motor noise and a strategy for joint stability.