However, its potential to counteract motor fatigability, a reduction in motor performance during sustained movements, remains underinvestigated. This could be relevant in neurological conditions such as multiple sclerosis, where increased motor fatigability is a prominent symptom. One form of motor fatigability is motor slowing, a decline in movement speed over time evoked by fast, repetitive movements.
In this study, we investigated whether the possibility to earn reward attenuates motor slowing, and examined associated changes in muscle activity and pupil size, a putative marker of physical effort. Participants performed a wrist tapping task at maximal voluntary speed with or without the possibility of earning a reward. We found that wrist tapping induced motor slowing and that slowing was significantly reduced by reward.
Over time, tapping became more costly as indicated by higher muscle activity and coactivation per tap. This was accompanied by a sustained pupil dilation, which could not solely be explained by tapping speed. These findings suggest that, rather than restoring efficient motor control, reward attenuates motor slowing by allowing participants to access a performance reserve and invest more resources into the task, reflected by increased muscle activation per tap and sustained pupil dilation.
The authors would like to thank all participants for their involvement in the study. We are especially grateful to Nathalie Buchmann for her assistance with data collection, Dr. Daniel Woolley for his technical support, and Dr.
Snow (Xue) Zhang for her valuable contributions throughout the project. We also thank Paige Howell for proof-reading, Eduardo Villar for the drawing of the experimental setup, and the Seminar for Statistics at ETH Zurich for statistical consulting. This work was supported by the Swiss National Science Foundation (SNSF) grant 32003B_207719.
S.N.M is supported by the SNSF starting grant TMSGI1_226129. N.W. is supported by the National Research Foundation, Prime Minister’s Office, Singapore under its Campus for Research Excellence and Technological Enterprise (CREATE) programme. Open access funding provided by Swiss Federal Institute of Technology Zurich.
Extract — continue reading at the source.
