title: Modulating conscious movement intention by noninvasive brain stimulation and the underlying neural mechanisms.
abstract: Conscious intention is a fundamental aspect of the human experience. Despite long-standing interest in the basis and implications of intention, its underlying neurobiological mechanisms remain poorly understood. Using high-definition transcranial DC stimulation (tDCS), we observed that enhancing spontaneous neuronal excitability in both the angular gyrus and the primary motor cortex caused the reported time of conscious movement intention to be ∼60-70 ms earlier. Slow brain waves recorded ∼2-3 s before movement onset, as well as hundreds of milliseconds after movement onset, independently correlated with the modulation of conscious intention by brain stimulation. These brain activities together accounted for 81% of interindividual variability in the modulation of movement intention by brain stimulation. A computational model using coupled leaky integrator units with biophysically plausible assumptions about the effect of tDCS captured the effects of stimulation on both neural activity and behavior. These results reveal a temporally extended brain process underlying conscious movement intention that spans seconds around movement commencement.
authors.affiliation: National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892.
authors.forename: Zachary H
authors.initials: ZH
authors.lastname: Douglas
authors.affiliation: National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892.
authors.forename: Brian
authors.initials: B
authors.lastname: Maniscalco
authors.affiliation: National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892.
authors.forename: Mark
authors.identifier: http://orcid.org/0000-0002-3180-6811
authors.initials: M
authors.lastname: Hallett
authors.affiliation: National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892.
authors.forename: Eric M
authors.identifier: http://orcid.org/0000-0003-0628-0210
authors.initials: EM
authors.lastname: Wassermann
authors.affiliation: National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892 biyu.jade.he@gmail.com.
authors.forename: Biyu J
authors.identifier: http://orcid.org/0000-0003-1549-1351
authors.initials: BJ
authors.lastname: He
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods; D000328:Adult; D003243:Consciousness / Q000502:physiology*; D004569:Electroencephalography / Q000379:methods; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D009044:Motor Cortex / Q000502:physiology*; D009068:Movement / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D011597:Psychomotor Performance / Q000502:physiology; D065908:Transcranial Direct Current Stimulation / Q000379:methods*; D055815:Young Adult
keywords: EEG; movement intention; slow cortical potential; spontaneous activity; tDCS; volition