Task-relevant visual feedback uncertainty attenuates visuomotor adaptation.

Area of Science:

• Neuroscience
• Motor Control
• Human Movement Science

Background:

• Motor adaptation typically decreases with uncertain sensory feedback.
• Previous studies suggested this attenuation might not apply to large visual errors when feedback is task-irrelevant.
• The role of uncertainty in task-relevant feedback for large errors remained unclear.

Purpose of the Study:

• To investigate if motor adaptation to large perturbations is attenuated by uncertainty in task-relevant visual feedback.
• To determine the impact of visual feedback uncertainty on both implicit and explicit adaptation processes.

Main Methods:

• Participants performed a visuomotor rotation task with varying levels of visual feedback uncertainty (low vs. high).
• The error-clamp method was used in a second experiment to isolate implicit adaptation.
• Implicit and explicit adaptation contributions were quantified across different feedback conditions.

Main Results:

• High visual feedback uncertainty significantly reduced both the initial and final extent of motor adaptation.
• Implicit adaptation was consistently smaller under high feedback uncertainty compared to low uncertainty.
• Explicit adaptation contributions were minimal, especially under high uncertainty.

Conclusions:

• Task-relevant visual feedback uncertainty influences implicit motor adaptation, even for large errors.
• The motor system is sensitive to feedback reliability and adjusts learning rates accordingly.
• Adaptation depends on the assessment of both sensory prediction errors and target errors.