Motor imagery in REM sleep is increased by transcranial direct current stimulation of the left motor cortex (C3).

Applying anodal transcranial direct current stimulation (tDCS) over the motor cortex (C3) during REM sleep increases both the quantity and quality of spontaneous motor imagery, including athletic motor imagery, compared to cathodal or sham stimulation. A randomized triple-blinded design combined neurophysiological techniques with quantitative analysis of mentation reports. The findings suggest that electrophysiological manipulation of motor imagery in REM sleep could eventually support rehabilitative tDCS protocols for temporarily immobile patients, such as those with dementia, infants with motor disorders, or coma patients, who cannot perform specific motor imagery tasks.

Study at a glance

Abstract

This study investigates if anodal transcranial direct current stimulation (tDCS) of areas above the motor cortex (C3) influences the quantity and quality of spontaneous motor imagery experienced in REM sleep. A randomized triple-blinded design was used, combining neurophysiological techniques with a tool of quantitative mentation report analysis developed from cognitive linguistics and generative grammar. The results indicate that more motor imagery, and more athletic motor imagery, is induced by anodal tDCS in comparison to cathodal and sham tDCS. This insight may have implications beyond basic consciousness research. Motor imagery in REM sleep has been hypothesized to serve the rehearsal of motor movements, which benefits later motor performance. Electrophysiological manipulations of motor imagery in REM sleep could in the long run be used for rehabilitative tDCS protocols benefitting temporarily immobile clinical patients, especially those who cannot perform specific motor imagery tasks - such as dementia patients, infants with developmental and motor disorders, and coma patients.