title: Cognitive Enhancement Induced by Anodal tDCS Drives Circuit-Specific Cortical Plasticity.
abstract: Increasing evidence shows that anodal transcranial direct current stimulation (tDCS) enhances cognitive performance in healthy and clinical population. Such facilitation is supposed to be linked to plastic changes at relevant cortical sites. However, direct electrophysiological evidence for this causal relationship is still missing. Here, we show that cognitive enhancement occurring in healthy human subjects during anodal tDCS is affected by ongoing brain activity, increasing cortical excitability of task-related brain networks only, as directly measured by Transcranial Magnetic Stimulation combined with electroencephalography (TMS-EEG). Specifically, TMS-EEG recordings were performed before and after anodal tDCS coupled with a verbal fluency task. To control for effects of tDCS protocol and TMS target location, 3 conditions were assessed: anodal/sham tDCS with TMS over left premotor cortex, anodal tDCS with TMS over left posterior parietal cortex. Modulation of cortical excitability occurred only at left Brodmann's areas 6, 44, and 45, a key network for language production, after anodal tDCS and TMS over the premotor cortex, and was positively correlated to the degree of cognitive enhancement. Our results suggest that anodal tDCS specifically affects task-related functional networks active while delivering stimulation, and this boost of specific cortical circuits is correlated to the observed cognitive enhancement.
authors.affiliation: Department of Psychology, Università degli Studi di Milano-Bicocca, Milano 20126, Italy.|NeuroMi, Milan Center for Neuroscience, Milano 20126, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Pisoni
authors.affiliation: Department of Psychology, Università degli Studi di Milano-Bicocca, Milano 20126, Italy.|NeuroMi, Milan Center for Neuroscience, Milano 20126, Italy.
authors.forename: Giulia
authors.initials: G
authors.lastname: Mattavelli
authors.affiliation: Department of Psychology, Università degli Studi di Milano-Bicocca, Milano 20126, Italy.|NeuroMi, Milan Center for Neuroscience, Milano 20126, Italy.|CeRiN - Centro di Riabilitazione Neurocognitiva, Università degli Studi di Trento, Rovereto 38068, Italy.
authors.forename: Costanza
authors.initials: C
authors.lastname: Papagno
authors.affiliation: Department of Clinical Sciences, "Luigi Sacco", Università degli Studi di Milano, Milano 20157, Italy.|Fondazione Europea di Ricerca Biomedica, FERB Onlus, Cernusco sul Naviglio 20063, Milano, Milano, Italy.
authors.forename: Mario
authors.initials: M
authors.lastname: Rosanova
authors.affiliation: Institute of Science and Technology, Federal University of São Paulo, São José dos Campos 12231-280, Brazil.
authors.forename: Adenauer G
authors.initials: AG
authors.lastname: Casali
authors.affiliation: Department of Psychology, Università degli Studi di Milano-Bicocca, Milano 20126, Italy.|NeuroMi, Milan Center for Neuroscience, Milano 20126, Italy.
authors.forename: Leonor J
authors.initials: LJ
authors.lastname: Romero Lauro
mesh_terms: D000328:Adult; D058256:Brain Waves / Q000502:physiology*; D002540:Cerebral Cortex / Q000502:physiology*; D003071:Cognition / Q000502:physiology*; D004569:Electroencephalography; D005260:Female; D006801:Humans; D008297:Male; D009415:Nerve Net / Q000502:physiology*; D009473:Neuronal Plasticity / Q000502:physiology*; D012660:Semantics; D065908:Transcranial Direct Current Stimulation / Q000379:methods*; D050781:Transcranial Magnetic Stimulation / Q000379:methods; D014705:Verbal Behavior; D055815:Young Adult