title: Transcranial electrical stimulation of the occipital cortex during visual perception modifies the magnitude of BOLD activity: A combined tES-fMRI approach.
abstract: The aim of this study was to investigate if the blood oxygenation level-dependent (BOLD) changes in the visual cortex can be used as biomarkers reflecting the online and offline effects of transcranial electrical stimulation (tES). Anodal transcranial direct current stimulation (tDCS) and 10Hz transcranial alternating current stimulation (tACS) were applied for 10min duration over the occipital cortex of healthy adults during the presentation of different visual stimuli, using a crossover, double-blinded design. Control experiments were also performed, in which sham stimulation as well as another electrode montage were used. Anodal tDCS over the visual cortex induced a small but significant further increase in BOLD response evoked by a visual stimulus; however, no aftereffect was observed. Ten hertz of tACS did not result in an online effect, but in a widespread offline BOLD decrease over the occipital, temporal, and frontal areas. These findings demonstrate that tES during visual perception affects the neuronal metabolism, which can be detected with functional magnetic resonance imaging (fMRI).
authors.affiliation: Department of Clinical Neurophysiology, University Medical Center Göttingen, Georg-August University Göttingen, 37075 Göttingen, Germany. Electronic address: ivan.alekseichuk@med.uni-goettingen.de.
authors.forename: Ivan
authors.initials: I
authors.lastname: Alekseichuk
authors.affiliation: Department of Psychology, Dresden University of Technology, 01062 Dresden, Germany.
authors.forename: Kersten
authors.initials: K
authors.lastname: Diers
authors.affiliation: Department of Clinical Neurophysiology, University Medical Center Göttingen, Georg-August University Göttingen, 37075 Göttingen, Germany.
authors.forename: Walter
authors.initials: W
authors.lastname: Paulus
authors.affiliation: Department of Clinical Neurophysiology, University Medical Center Göttingen, Georg-August University Göttingen, 37075 Göttingen, Germany.
authors.forename: Andrea
authors.initials: A
authors.lastname: Antal
mesh_terms: D000328:Adult; D001931:Brain Mapping / Q000379:methods; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009473:Neuronal Plasticity / Q000502:physiology; D009778:Occipital Lobe / Q000502:physiology*; D010100:Oxygen / Q000378:metabolism*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D065908:Transcranial Direct Current Stimulation / Q000379:methods*; D014793:Visual Cortex / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*
chemical_list: D010100:Oxygen
keywords: Occipital cortex; Visual perception; fMRI; tACS; tDCS