The left hand disrupts subsequent right hand grasping when their actions overlap

Area of Science:

• Neuroscience
• Motor Control
• Cognitive Psychology

Background:

• Adaptive motor control relies on movement minimization, which is supported by sensorimotor memory.
• The precise nature and operational conditions of sensorimotor memory remain incompletely understood, particularly in intermanual contexts.

Purpose of the Study:

• To investigate the conditions under which sensorimotor memory influences motor control across different hands (intermanual transfer).
• To test the predictive power of target feature-overlap, partial effector-overlap, and action-goal conjunction hypotheses on intermanual sensorimotor memory transfer.

Main Methods:

• Three experiments were conducted where participants performed actions with their left hand (grasping, estimating size, pinching, looking, resting) before grasping with their right hand.
• The primary metric analyzed was the in-flight anticipatory grip aperture of the right-hand grasps.
• Factors manipulated included object size overlap, effector overlap, and haptic feedback availability.

Main Results:

• The anticipatory grip aperture of the right hand was significantly influenced only when preceded by left-hand grasps.
• Overlap in object size, partial effector overlap, and haptic feedback availability did not affect the right-hand grasp metric.
• These findings indicate that simple sensory or effector similarity is insufficient to engage intermanual sensorimotor memory.

Conclusions:

• Intermanual transfer of sensorimotor memory for grasp execution is critically dependent on the conjunction of action type and action goal.
• The results support the action-goal conjunction hypothesis over simpler overlap-based predictions.
• Sensorimotor memory's role in adaptive motor control is more nuanced, requiring specific goal-directed congruence for cross-effector influence.