Reaction-time (RT) movements are internally planned in the brain. Presumably, proactive control in RT movements appears as an inhibitory phase preceding movement execution. We identified the brain activity of RT movements in close proximity to movement onset and compared it to similar self-paced (SP) voluntary movements without external command.
We recorded 18 healthy participants performing RT and SP fast index finger abductions with 306-sensor magnetoencephalography and EMG. RT movements were performed as responses to cutaneous electrical stimulation delivered on the hand radial nerve area. Motor field (MF) and movement-evoked field 1 (MEF1) corresponding to the sensorimotor cortex activity during motor execution and afferent feedback after the movement were analyzed with Brainstorm’s scouts using regions of interest analysis.
Primary motor (M1) and sensory (S1) cortices were active before and after movement onset. During RT movements, M1-S1 cortices showed higher activation compared to SP movements. In M1, stronger preparatory activity was seen in SP than in RT.
Both M1 and S1 cortices participated in the movement execution and in the prediction of sensory consequences of movement. Cutaneous stimulation facilitated cortical activation during MF after RT movements, implying the applicability of cutaneous stimulation in motor rehabilitation.
1Faculty of Sport and Health Sciences, and the Jyväskylä Centre for Interdisciplinary Brain Research, University of Jyväskylä, Finland
Author disclosures: This study was funded by the Juho Vainio Foundation, Helsinki, Finland, (201410296) and the Jenny & Antti Wihuri Foundation, Helsinki, Finland (00170073).
Address for correspondence: Pekka Hautasaari, MSc, pt, Faculty of Sport and Health Sciences, University of Jyväskylä, P.O. Box 35, FI-40014 Finland, firstname.lastname@example.org, ORCIDs: Ina Tarkka: 0000-0002-7552-5819, Pekka Hautasaari: 0000-0002-0403-9602