The impact of dwell time on the contextual effect of visual and passive lead-in movements

Contextual cues arising from distinct movements are crucial in shaping control strategies for human movement. Here, we examine the impact of visual and passive lead-in movement cues on unimanual motor learning, focusing on the influence of “dwell time”, in which two-part movements are separated by the interval between the end of the first movement and the start of the second. We used a robotic manipulandum to implement a point-to-point interference task with switching opposing viscous curl-fields in male and female human participants. Consistent with prior research, in both visual and passive lead-in conditions, participants showed significant adaptation to opposing dynamics with short dwell times. As dwell time increased for both visual and passive signals, past movement information had less contextual influence. However, the efficacy of visual movement cues declined faster as dwell times increased. At dwell times greater than 800ms, the contextual influence of prior visual movement was small, whereas the effectiveness of passive lead-in movement was found to be significantly greater. This indicates that the effectiveness of sensory movement cues in motor learning is modality-dependent. We hypothesize that such differences may arise because proprioceptive signals directly relate to arm movements, whereas visual inputs can relate to many aspects of movement in the environment and not just to our own arm movements. Therefore, the motor system may not always find them as relevant for predictive control of dynamics.

Significance Statement

This study reveals the critical role of contextual cues from distinct movements in shaping motor learning. Here, we examined the influence of “dwell time”, the interval between the end of the first and the start of the second movement. Notably, visual lead-in movement cues lose their effectiveness sooner than passive lead-in movement cues as dwell time increases. This is possibly due to their lesser relevance to self-generated movements and the longer processing delays in visual information. This finding underscores the modality-dependent nature of sensory cues in motor learning. Understanding these effects can inform the development of more effective rehabilitation and training programs by leveraging the strengths of different sensory modalities to optimize motor learning.

News & Noteworthy

This research uncovers, for the first time, how visual and proprioceptive sensory cues affect motor learning as a function of the pause or “dwell time” in two-part movements. The study has shown that visual lead-in movement cues lose their effectiveness sooner than passive lead-in movement cues as dwell time increases. By revealing the modality-dependent nature of sensory information, this study enhances our understanding of motor control and opens new possibilities for improving therapeutic interventions.