Consistent visuomotor adaptations and generalizations can be achieved through different rotations of robust motor...

Area of Science:

• Neuroscience
• Motor Control
• Biomechanics

Background:

• Human motor control relies on adapting motor commands to environmental changes.
• Motor adaptations are theorized to involve tuning of muscle synergies, which are combinations of muscle activations.
• Previous research suggests motor adaptations are achieved by adjusting the recruitment of these synergy modules.

Purpose of the Study:

• To investigate if different orders of exposure to visuomotor perturbations yield distinct muscle synergy tunings.
• To determine if varying synergistic tunings explain different patterns of adaptation generalization.
• To confirm muscle synergies as invariant motor primitives dynamically tuned during adaptation.

Main Methods:

• Healthy participants were exposed to two visuomotor rotation perturbations in different orders.
• Muscle synergy activation patterns were analyzed before and after perturbations.
• Adaptation and generalization of motor commands to untrained workspace regions were assessed.

Main Results:

• Different orders of perturbation exposure resulted in distinct tunings of the same set of muscle synergies.
• Despite different tunings, the net biomechanical adaptation patterns were consistent across exposure orders.
• The characteristics of synergy tunings correlated with the extent of generalization to untrained movements.

Conclusions:

• Muscle synergies serve as invariant motor primitives for natural movements.
• The recruitment of these synergies is dynamically tuned during motor adaptation processes.
• Synergy tuning patterns influence how motor adaptations generalize to novel scenarios.