Temporal Dynamics of Sensorimotor Integration for Auditory and Proprioceptive Target Information During Movement Preparation and Execution

Endpoint movement variability in non-visual (auditory and proprioceptive) target reaching is modality-dependent. This study investigated whether such modality-specific effects may emerge during movement preparation and how they unfold during movement execution. Participants performed reaching movements toward auditory, proprioceptive, or audio-proprioceptive targets. Electromyography and movement kinematics were recorded to examine the effect of target-related sensory modality on sensory encoding and coordination of motor commands during movement preparation, as well as their effect on movement execution. Results revealed a modality-dependent sensory encoding phase, whereas a modality-independent coordination of motor commands. While the target modality did not affect movement initiation, it modulated the subsequent movement execution. These findings demonstrate that, in non-visual target reaching, the effect of target-related sensory modality extends beyond execution to specific phases of movement preparation. Our results support a four-stage model of action control toward non-visual targets, consisting of a modality-dependent sensory encoding phase of movement preparation and early execution, as well as a modality-independent motor coordination and movement initiation. These findings provide new insights into the temporal dynamics of sensorimotor control without vision, suggesting a different use of non-visual (proprioceptive and auditory) target-related sensory information during distinct phases of movement preparation and execution.