title: Modulation of large-scale brain networks by transcranial direct current stimulation evidenced by resting-state functional MRI.
abstract: BACKGROUND
  Brain areas interact mutually to perform particular complex brain functions such as memory or language. Furthermore, under resting-state conditions several spatial patterns have been identified that resemble functional systems involved in cognitive functions. Among these, the default-mode network (DMN), which is consistently deactivated during task periods and is related to a variety of cognitive functions, has attracted most attention. In addition, in resting-state conditions some brain areas engaged in focused attention (such as the anticorrelated network, AN) show a strong negative correlation with DMN; as task demand increases, AN activity rises, and DMN activity falls.
  
  
  OBJECTIVE
  We combined transcranial direct current stimulation (tDCS) with functional magnetic resonance imaging (fMRI) to investigate these brain network dynamics.
  
  
  METHODS
  Ten healthy young volunteers underwent four blocks of resting-state fMRI (10-minutes), each of them immediately after 20 minutes of sham or active tDCS (2 mA), on two different days. On the first day the anodal electrode was placed over the left dorsolateral prefrontal cortex (DLPFC) (part of the AN) with the cathode over the contralateral supraorbital area, and on the second day, the electrode arrangement was reversed (anode right-DLPFC, cathode left-supraorbital).
  
  
  RESULTS
  After active stimulation, functional network connectivity revealed increased synchrony within the AN components and reduced synchrony in the DMN components.
  
  
  CONCLUSIONS
  Our study reveals a reconfiguration of intrinsic brain activity networks after active tDCS. These effects may help to explain earlier reports of improvements in cognitive functions after anodal-tDCS, where increasing cortical excitability may have facilitated reconfiguration of functional brain networks to address upcoming cognitive demands.
authors.affiliation: Departament de Psiquiatria i Psicobiologia Clínica, Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain.
authors.forename: Cleofé
authors.initials: C
authors.lastname: Peña-Gómez
authors.affiliation: Departament de Psiquiatria i Psicobiologia Clínica, Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain.
authors.forename: Roser
authors.initials: R
authors.lastname: Sala-Lonch
authors.affiliation: Departament de Psiquiatria i Psicobiologia Clínica, Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain; Institut d'Investigacions Biomèdiques August Pi i Sunyer, Barcelona, Spain.
authors.forename: Carme
authors.initials: C
authors.lastname: Junqué
authors.affiliation: Departament de Psiquiatria i Psicobiologia Clínica, Facultat de Psicologia, Universitat de Barcelona, Barcelona, Spain.
authors.forename: Immaculada C
authors.initials: IC
authors.lastname: Clemente
authors.affiliation: Departament de Psiquiatria i Psicobiologia Clínica, Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain.
authors.forename: Dídac
authors.initials: D
authors.lastname: Vidal
authors.affiliation: Institut d'Investigacions Biomèdiques August Pi i Sunyer, Barcelona, Spain; Centre de Diagnòstic per la Imatge, Hospital Clínic de Barcelona, Barcelona, Spain.
authors.forename: Núria
authors.initials: N
authors.lastname: Bargalló
authors.affiliation: Institut d'Investigacions Biomèdiques August Pi i Sunyer, Barcelona, Spain; CIBER-BBN, Barcelona, Catalonia, Spain.
authors.forename: Carles
authors.initials: C
authors.lastname: Falcón
authors.affiliation: Institut d'Investigacions Biomèdiques August Pi i Sunyer, Barcelona, Spain; Laboratori d'Exploracions Neurofuncionals, Hospital Clínic de Barcelona, Spain.
authors.forename: Josep
authors.initials: J
authors.lastname: Valls-Solé
authors.affiliation: Berenson-Allen Center for Non-Invasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts; Institut Universitari de Neurorehabilitació Guttmann-UAB, Badalona, Spain.
authors.forename: Álvaro
authors.initials: Á
authors.lastname: Pascual-Leone
authors.affiliation: Departament de Psiquiatria i Psicobiologia Clínica, Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain; Institut d'Investigacions Biomèdiques August Pi i Sunyer, Barcelona, Spain. Electronic address: dbartres@ub.edu.
authors.forename: David
authors.initials: D
authors.lastname: Bartrés-Faz
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000328:Adult; D001921:Brain / Q000502:physiology*; D019317:Evidence-Based Medicine; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009415:Nerve Net / Q000502:physiology*; D012146:Rest / Q000502:physiology*; D050781:Transcranial Magnetic Stimulation / Q000379:methods*