Role of perceptual improvement induced by repetitive somatosensory stimulation on motor behaviour

Somatosensory signals are essential to the motor system control and tactile impairments can result in significant reduction on the quality of motor abilities. Repetitive somatosensory stimulation (RSS) at a finger is known to improve performance in a two-points discrimination task (2PDT), supposedly thanks to the increase of the cortical representation of the stimulated body part in the somatosensory cortices. Yet, whether the RSS induced improvement on touch perception affects the activity of the motor cortex remains unknown. Here we assessed the effects of RSS on the motor system. Tactile performance and motor skills were evaluated before and after 3 hours training phase by using a 2PDT and a pegboard task. The training phase consisted of a real RSS, and a sham RSS. Results showed that the tactile performance increased for the trained finger (right index) only after the real RSS. Results on motor performance showed that reaction times were shorter for the right hand only in the group trained with sham RSS, whereas number of drops for the pegboard task were reduced for the left hand only in the real RSS trained group. We suggest that RSS can have an effect on the participants motor performance possibly through sensorimotor interactions.