Implicit adaptation's effect on sensorimotor and motor confidence.

Area of Science:

• Neuroscience
• Motor Control
• Cognitive Psychology

Background:

• Sensorimotor adaptation is crucial for maintaining movement accuracy.
• Adaptation can be explicit (conscious) or implicit (unconscious).
• Explicit adaptation reduces sensorimotor confidence, but implicit adaptation's effect is unknown.

Purpose of the Study:

• To investigate if implicit sensorimotor adaptation affects confidence in sensorimotor judgments.
• To determine if implicit adaptation influences motor awareness (proprioception).

Main Methods:

• Participants performed reaching movements with visual feedback manipulated to induce implicit adaptation ('error-clamped' trajectory).
• Confidence was reported by adjusting arc size, with rewards for accurate reports.
• Fourier analysis assessed adaptation and awareness changes over trials.

Main Results:

• Implicit sensorimotor adaptation was robust, evidenced by sinusoidal changes in reach and report time series.
• Motor awareness showed corresponding changes, indicating adaptation influenced proprioceptive judgments.
• Confidence judgments were not consistently affected by implicit adaptation.

Conclusions:

• Implicit sensorimotor adaptation, though unconscious, can bias judgments of movement outcomes due to sensorimotor signal mismatches.
• Sensorimotor confidence and confidence in proprioceptive awareness appear to be regulated by partially distinct neural mechanisms.