Context Versus Aiming Under Uncertainty When Both Feedforward and Feedback Control Are Engaged.

Area of Science:

• Neuroscience
• Motor Control
• Cognitive Psychology

Background:

• Motor learning theories posit that movement plans adapt based on sensory feedback.
• Adaptation is assumed to inversely correlate with sensory uncertainty, especially when online feedback is limited.

Purpose of the Study:

• To investigate how sensory uncertainty influences motor learning and adaptation when online feedback is not restricted.
• To explore if sensory uncertainty acts as a contextual cue for selecting internal models in motor control.

Main Methods:

• Participants performed reaching movements under perturbed conditions with varying sensory feedback uncertainty.
• Movement adjustments and trial-to-trial changes in reach direction were analyzed.
• Computational models were used to assess the influence of sensory uncertainty and error on motor adaptation.

Main Results:

• Motor adaptation showed a gradual error reduction envelope across trials.
• Abrupt changes in initial reach direction correlated with previous trial's sensory uncertainty, not error magnitude.
• Models where uncertainty modulates an aiming process best explained the observed behavior.

Conclusions:

• Sensory uncertainty plays a critical role in motor adaptation, influencing aiming processes.
• Uncertainty may act as a contextual cue, modulating the selection of internal models for motor control.
• Findings challenge traditional views of motor learning by highlighting the distinct roles of error and uncertainty.