title: Effects of Anodal High-Definition Transcranial Direct Current Stimulation on Bilateral Sensorimotor Cortex Activation During Sequential Finger Movements: An fNIRS Study.
abstract: Transcranial direct current stimulation (tDCS) is a non-invasive electrical brain stimulation technique that can modulate cortical neuronal excitability and activity. This study utilized functional near infrared spectroscopy (fNIRS) neuroimaging to determine the effects of anodal high-definition (HD)-tDCS on bilateral sensorimotor cortex (SMC) activation. Before (Pre), during (Online), and after (Offline) anodal HD-tDCS (2 mA, 20 min) targeting the left SMC, eight healthy subjects performed a simple finger sequence (SFS) task with their right or left hand in an alternating blocked design (30-s rest and 30-s SFS task, repeated five times). In order to determine the level of bilateral SMC activation during the SFS task, an Oxymon MkIII fNIRS system was used to measure from the left and right SMC, changes in oxygenated (O2Hb) and deoxygenated (HHb) haemoglobin concentration values. The fNIRS data suggests a finding that compared to the Pre condition both the "Online" and "Offline" anodal HD-tDCS conditions induced a significant reduction in bilateral SMC activation (i.e., smaller decrease in HHb) for a similar motor output (i.e., SFS tap rate). These findings could be related to anodal HD-tDCS inducing a greater efficiency of neuronal transmission in the bilateral SMC to perform the same SFS task.
authors.affiliation: Movement to Health (M2H) Laboratory, EuroMov, University of Montpellier, Montpellier, France. makii.muthalib@gmail.com.
authors.forename: Makii
authors.initials: M
authors.lastname: Muthalib
authors.affiliation: Movement to Health (M2H) Laboratory, EuroMov, University of Montpellier, Montpellier, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Besson
authors.affiliation: Institute of Neurology, University College London, London, UK.
authors.forename: John
authors.initials: J
authors.lastname: Rothwell
authors.affiliation: Department of Electronic Engineering, National University of Ireland, Maynooth, Ireland.
authors.forename: Tomas
authors.initials: T
authors.lastname: Ward
authors.affiliation: Movement to Health (M2H) Laboratory, EuroMov, University of Montpellier, Montpellier, France.
authors.forename: Stephane
authors.initials: S
authors.lastname: Perrey
mesh_terms: D000328:Adult; D005385:Fingers / Q000502:physiology*; D006801:Humans; D009068:Movement; D010108:Oxyhemoglobins / Q000032:analysis; D066191:Sensorimotor Cortex / Q000502:physiology*; D019265:Spectroscopy, Near-Infrared / Q000379:methods*; D065908:Transcranial Direct Current Stimulation
chemical_list: D010108:Oxyhemoglobins
keywords: Functional near-infrared spectroscopy; Neuromodulation; Neuroplasticity; Sensorimotor cortex; tDCS