title: Modulating arithmetic fact retrieval: a single-blind, sham-controlled tDCS study with repeated fMRI measurements.
abstract: Transcranial direct current stimulation (tDCS) is a non-invasive technique which has been used to modulate various cognitive functions in healthy participants as well as stroke patients. Despite the increasing number of tDCS studies, it still remains questionable whether tDCS is suitable for modulating performance in arithmetic tasks and whether a single tDCS session may cause brain activity changes that can be detected with functional magnetic resonance imaging (fMRI). We asked healthy participants to repeatedly solve simple multiplication tasks in three conditions: STIMULATION (anodal tDCS over the right angular gyrus, AG), SHAM (identical electrode set-up without stimulation), and CONTROL (no electrodes attached). Before and after tDCS, we used fMRI to examine changes in brain activity. Behavioural results indicate that a single session of tDCS did not modulate task performance significantly. However, fMRI measurements revealed that the neural correlates of multiplication were modified following a single session of anodal tDCS. In the bilateral AG, activity was significantly higher for multiplication problems rehearsed during active tDCS, as compared to multiplication problems rehearsed without tDCS or during sham tDCS. In sum, we present first neuro-functional evidence that tDCS modulates arithmetic processing. Implications of these findings for future tDCS studies and for the rehabilitation of acalculic patients with deficits in arithmetic fact retrieval are discussed.
authors.affiliation: Neurological Clinic, Section Neuropsychology, RWTH Aachen University, Aachen, Germany. clemens@neuropsych.rwth-aachen.de
authors.forename: Benjamin
authors.initials: B
authors.lastname: Clemens
authors.forename: Stefanie
authors.initials: S
authors.lastname: Jung
authors.forename: Mikhail
authors.initials: M
authors.lastname: Zvyagintsev
authors.forename: Frank
authors.initials: F
authors.lastname: Domahs
authors.forename: Klaus
authors.initials: K
authors.lastname: Willmes
mesh_terms: D000328:Adult; D001921:Brain / Q000098:blood supply / Q000502:physiology; D001931:Brain Mapping; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008433:Mathematics; D011939:Mental Recall / Q000502:physiology*; D008875:Middle Aged; D010100:Oxygen; D011340:Problem Solving / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D016037:Single-Blind Method; D050781:Transcranial Magnetic Stimulation
chemical_list: D010100:Oxygen