Transcranial direct current stimulation facilitates category learning

Benjamin C Gibson; Teagan S Mullins; Melissa D Heinrich; Katie Witkiewitz; Alfred B Yu; Jeffrey T Hansberger; Vincent P Clark

doi:10.1016/j.brs.2019.11.010

Transcranial direct current stimulation facilitates category learning

Brain Stimul. 2020 Mar-Apr;13(2):393-400. doi: 10.1016/j.brs.2019.11.010. Epub 2019 Nov 26.

Authors

Benjamin C Gibson¹, Teagan S Mullins¹, Melissa D Heinrich¹, Katie Witkiewitz², Alfred B Yu³, Jeffrey T Hansberger⁴, Vincent P Clark⁵

Affiliations

¹ Psychology Clinical Neuroscience Center, Dept. Psychology, MSC03-2220, University of New Mexico, Albuquerque, NM, 87131, USA; Department of Psychology, University of New Mexico, Albuquerque, NM, 87131, USA.
² Department of Psychology, University of New Mexico, Albuquerque, NM, 87131, USA; Center on Alcoholism, Substance Abuse, & Addictions, Albuquerque, NM, 87106, USA.
³ CCDC, Army Research Laboratory, Human Research and Engineering Directorate, Aberdeen Proving Ground, MD, 21005, USA.
⁴ CCDC, Army Research Laboratory, Human Research and Engineering Directorate, Aberdeen Proving Ground, MD, 21005, USA; U.S. Army Research Laboratory, Huntsville, AL, 35898, USA.
⁵ Psychology Clinical Neuroscience Center, Dept. Psychology, MSC03-2220, University of New Mexico, Albuquerque, NM, 87131, USA; Department of Psychology, University of New Mexico, Albuquerque, NM, 87131, USA; The Mind Research Network of the Lovelace Biomedical Research Institute, 1101 Yale Blvd. NE, Albuquerque, NM, 87106, USA. Electronic address: vclark@unm.edu.

PMID: 31848068
DOI: 10.1016/j.brs.2019.11.010

Abstract

Background: After two decades of transcranial direct current stimulation (tDCS) research, it is still unclear which applications benefit most from which tDCS protocols. One prospect is the acceleration of learning, where previous work has demonstrated that anodal tDCS applied to the right ventrolateral prefrontal cortex (rVLPFC) is capable of doubling the rate of learning in a visual camouflaged threat detection and category learning task.

Goals: Questions remain as to the specific cognitive mechanisms underlying this learning enhancement, and whether it generalizes to other tasks. The goal of the current project was to expand previous findings by employing a novel category learning task.

Methods: Participants learned to classify pictures of European streets within a discovery learning paradigm. In a double-blind design, 54 participants were randomly assigned to 30 min of tDCS using either 2.0 mA anodal (n = 18), cathodal (n = 18), or 0.1 mA sham (n = 18) tDCS over the rVLPFC.

Results: A linear mixed-model revealed a significant effect of tDCS condition on classification accuracy across training (p = 0.001). Compared to a 4.2% increase in sham participants, anodal tDCS over F10 increased performance by 20.6% (d = 1.71) and cathodal tDCS by 14.4% (d = 1.16).

Conclusions: These results provide further evidence for the capacity of tDCS applied to rVLPFC to enhance learning, showing a greater than quadrupling of test performance after training (491% of sham) in a difficult category learning task. Combined with our previous studies, these results suggest a generalized performance enhancement. Other tasks requiring sustained attention, insight and/or category learning may also benefit from this protocol.

Keywords: IFG; Learning; NIBS; Neuroplasticity; VLPFC; tDCS.

Publication types

Randomized Controlled Trial
Research Support, N.I.H., Extramural
Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

Adult
Attention
Double-Blind Method
Female
Humans
Learning*
Male
Prefrontal Cortex / physiology*
Transcranial Direct Current Stimulation / methods*

Grants and funding

P30 GM122734/GM/NIGMS NIH HHS/United States