title: Modulation of executive control in dual tasks with transcranial direct current stimulation (tDCS).
abstract: Executive processing in dual tasks is primarily associated with activation of the lateral prefrontal cortex (lPFC), which is demonstrated in functional imaging studies (e.g., Szameitat et al., 2006). However, a causal relation between lPFC activity and executive functions in dual tasks has not been demonstrated so far. Here, we used anodal transcranial direct current stimulation (atDCS [1 mA, 20 min] vs. sham stimulation [1 mA, 30s]) over the left inferior frontal junction under conditions of random and fixed task order in dual tasks as well as in single tasks in healthy young individuals (Experiment 1). We found that atDCS, if administered simultaneously to the task, improved performance in random-order dual tasks, but not in fixed-order dual tasks and single tasks. Moreover, dual-task performance under random-order conditions did not improve if atDCS was applied prior to the task performance. The identical procedure in Experiment 2 showed no difference in dual-task performance under random-task order conditions when we compared cathodal tDCS (ctDCS) with sham stimulation. Our findings suggest that dual-task performance is causally related to lPFC activation under conditions that require task-order decisions and high demands on executive functioning. Subsequent studies may now explore if atDCS leads to sustained improvements parallel to the training of dual tasks.
authors.affiliation: Department of Psychology, Humboldt University Berlin, Rudower Chaussee 18, 12489 Berlin, Germany. Electronic address: tilo.strobach@hu-berlin.de.
authors.forename: Tilo
authors.initials: T
authors.lastname: Strobach
authors.affiliation: Department of Psychology, Humboldt University Berlin, Rudower Chaussee 18, 12489 Berlin, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Soutschek
authors.affiliation: Department of Neurology, NeuroCure Cluster of Excellence, and Center for Stroke Research Berlin, Charite Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Daria
authors.initials: D
authors.lastname: Antonenko
authors.affiliation: Department of Neurology, NeuroCure Cluster of Excellence, and Center for Stroke Research Berlin, Charite Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Agnes
authors.initials: A
authors.lastname: Flöel
authors.affiliation: Department of Psychology, Humboldt University Berlin, Rudower Chaussee 18, 12489 Berlin, Germany.
authors.forename: Torsten
authors.initials: T
authors.lastname: Schubert
mesh_terms: D000328:Adult; D055590:Electromagnetic Phenomena; D056344:Executive Function / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D017397:Prefrontal Cortex / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology*; D065908:Transcranial Direct Current Stimulation / Q000379:methods*; D055815:Young Adult
keywords: Dual tasks; Executive control; tDCS