title: Enhanced working memory performance via transcranial direct current stimulation: The possibility of near and far transfer.
abstract: Although working memory (WM) training programs consistently result in improvement on the trained task, benefit is typically short-lived and extends only to tasks very similar to the trained task (i.e., near transfer). It is possible that pairing repeated performance of a WM task with brain stimulation encourages plasticity in brain networks involved in WM task performance, thereby improving the training benefit. In the current study, transcranial direct current stimulation (tDCS) was paired with performance of a WM task (n-back). In Experiment 1, participants performed a spatial location-monitoring n-back during stimulation, while Experiment 2 used a verbal identity-monitoring n-back. In each experiment, participants received either active (2.0mA) or sham (0.1mA) stimulation with the anode placed over either the right or the left dorsolateral prefrontal cortex (DLPFC) and the cathode placed extracephalically. In Experiment 1, only participants receiving active stimulation with the anode placed over the right DLPFC showed marginal improvement on the trained spatial n-back, which did not extend to a near transfer (verbal n-back) or far transfer task (a matrix-reasoning task designed to measure fluid intelligence). In Experiment 2, both left and right anode placements led to improvement, and right DLPFC stimulation resulted in numerical (though not sham-adjusted) improvement on the near transfer (spatial n-back) and far transfer (fluid intelligence) task. Results suggest that WM training paired with brain stimulation may result in cognitive enhancement that transfers to performance on other tasks, depending on the combination of training task and tDCS parameters used.
authors.affiliation: Sandia National Laboratories, USA; Department of Psychology, The University of New Mexico, Albuquerque, NM, USA; Psychology Clinical Neuroscience Center, The University of New Mexico, Albuquerque, NM, USA. Electronic address: mctrumb@sandia.gov.
authors.forename: Michael C
authors.initials: MC
authors.lastname: Trumbo
authors.affiliation: Sandia National Laboratories, USA.
authors.forename: Laura E
authors.initials: LE
authors.lastname: Matzen
authors.affiliation: Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
authors.forename: Brian A
authors.initials: BA
authors.lastname: Coffman
authors.affiliation: Department of Psychology, The University of New Mexico, Albuquerque, NM, USA; Psychology Clinical Neuroscience Center, The University of New Mexico, Albuquerque, NM, USA.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Hunter
authors.affiliation: Department of Psychology, The University of New Mexico, Albuquerque, NM, USA; Psychology Clinical Neuroscience Center, The University of New Mexico, Albuquerque, NM, USA.
authors.forename: Aaron P
authors.initials: AP
authors.lastname: Jones
authors.affiliation: Department of Psychology, The University of New Mexico, Albuquerque, NM, USA; Psychology Clinical Neuroscience Center, The University of New Mexico, Albuquerque, NM, USA.
authors.forename: Charles S H
authors.initials: CSH
authors.lastname: Robinson
authors.affiliation: Department of Psychology, The University of New Mexico, Albuquerque, NM, USA; Psychology Clinical Neuroscience Center, The University of New Mexico, Albuquerque, NM, USA.
authors.forename: Vincent P
authors.initials: VP
authors.lastname: Clark
mesh_terms: D000293:Adolescent; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D007858:Learning / Q000502:physiology; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D009483:Neuropsychological Tests; D017397:Prefrontal Cortex / Q000502:physiology*; D011930:Reaction Time; D065852:Spatial Memory / Q000502:physiology; D013067:Speech Perception / Q000502:physiology; D013850:Thinking / Q000502:physiology; D065908:Transcranial Direct Current Stimulation / Q000379:methods; D055815:Young Adult
keywords: Brain stimulation; Fluid intelligence; Transcranial direct current stimulation; Transfer; Working memory