Temporal dynamics of sensorimotor integration for auditory and proprioceptive target information during movement preparation and execution

Actions toward non-visual targets exhibit modality-specific patterns of endpoint variability, with movements toward auditory targets being more variable than those toward proprioceptive or multisensory targets. However, whether such modality-specific effects emerge already during movement preparation and how they evolve across movement execution remains unclear. The present study addressed this question by asking participants to perform reaching movements toward auditory, proprioceptive, or audio-proprioceptive targets while electromyography and movement kinematics were recorded. Movement preparation and initiation was assessed by analyzing two temporal components of reaction time, premotor and motor, together with movement kinematics at peak acceleration. Movement execution was investigated by analyzing movement variability at peak velocity, deceleration, and endpoint. Results revealed a modality-dependent premotor reaction time. Kinematic analysis at peak acceleration showed no modality-specific differences, whereas movement variability was higher for auditory compared to proprioceptive and audio-proprioceptive targets from peak velocity onward. These findings suggest that, in non-visual target reaching, sensory modality shapes specific phases of movement preparation and the control of action execution, with motor initiation showing weaker, less reliable modality-dependent effects. This provides new insights into the temporal dynamics of sensorimotor control without vision, highlighting distinct roles of auditory and proprioceptive target information across the preparation and execution of reaching movements.