Arm cooling selectively impacts sensorimotor control

Abstract

The benefits of cold have long been recognized in sport and medicine. However, it also brings costs, which have more rarely been investigated, notably in terms of sensorimotor control. We hypothesized that in addition to peripheral effects, cold slows down the processing of proprioceptive cues, which has an impact on both feedback and feedforward control. We therefore compared the performances of participants whose right arm had been immersed in either cold water (arm temperature: 14°C) or lukewarm water (arm temperature: 34°C). In Experiment 1, we administered a Fitts's pointing task and performed a kinematic analysis to determine whether sensorimotor control processes were affected by the cold. Results revealed i) modifications in late kinematic parameters, suggesting changes in the use of proprioceptive feedback, and ii) modifications in early kinematic parameters, suggesting changes in action representations and/or feedforward processes. To explore our hypothesis further, we ran a second experiment in which no physical movement was involved, and thus no peripheral effects. Participants were administrated a hand laterality task, known to involve implicit motor imagery and assess the internal representation of the hand. They were shown left- and right-hand images randomly displayed in different orientations in the picture plane and had to identify as quickly and as accurately as possible whether each image was of the left hand or the right hand. Results revealed slower responses and more errors when participants had to mentally rotate the cooled hand in the extreme orientation of 160°, further suggesting the impact of cold on action representations.