Anodal tDCS Enhances Verbal Episodic Memory in Initially Low Performers

Habich, Annegret; Klöppel, Stefan; Abdulkadir, Ahmed; Scheller, Elisa; Nissen, Christoph; Peter, Jessica (2017). Anodal tDCS Enhances Verbal Episodic Memory in Initially Low Performers. Frontiers in human neuroscience, 11(542), p. 542. Frontiers Research Foundation 10.3389/fnhum.2017.00542

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The left dorsolateral prefrontal cortex (DLPFC) is involved in encoding and retrieval of episodic memories, and thus, is frequently targeted in non-invasive brain stimulation paradigms, aiming for its functional modulation. Anodal transcranial direct current stimulation (tDCS), that boosts neuronal excitability in stimulated cortical areas, has been found to increase cognitive skills differentially, depending on the initial performance. We hypothesize that the benefit of tDCS on verbal episodic memory can be extrapolated from the participants’ baseline performance. In the present randomized, double-blind, parallel group study, healthy young adults (n = 43) received either real anodal or sham tDCS over their left DLPFC during the encoding phase of a verbal episodic memory task. Forty words were presented visually thrice with immediate vocal retrieval after each block and an additional delayed recall. We conducted a moderation analysis to test the modulating effect of initial episodic memory retrieval, adjusted for primacy and recency effects, on delayed recall under real or sham stimulation. Despite the absence of a significantly beneficial tDCS effect at the group level, we found that the number of remembered midlist words in the first retrieval significantly moderated the stimulation effect in such a way that initially low performers experienced the highest gain from real stimulation. These results suggest that anodal tDCS to the left DLPFC improves memory functions only so far. While only marginal stimulation-induced gains occur in cognitively unimpaired populations, greater stimulation benefits might be expected in individuals with clinically relevant deficiencies in the verbal episodic memory domain.

Item Type:

Journal Article (Original Article)

Division/Institute:

04 Faculty of Medicine > University Psychiatric Services > University Hospital of Psychiatry and Psychotherapy > Translational Research Center
04 Faculty of Medicine > Department of Head Organs and Neurology (DKNS) > Clinic of Neurology
04 Faculty of Medicine > University Psychiatric Services > University Hospital of Geriatric Psychiatry and Psychotherapy
04 Faculty of Medicine > University Psychiatric Services > University Hospital of Psychiatry and Psychotherapy

UniBE Contributor:

Habich, Annegret; Klöppel, Stefan; Abdulkadir, Ahmed; Nissen, Christoph and Peter, Jessica

Subjects:

600 Technology > 610 Medicine & health

ISSN:

1662-5161

Publisher:

Frontiers Research Foundation

Language:

English

Submitter:

Katharina Klink

Date Deposited:

29 Dec 2017 13:32

Last Modified:

01 May 2018 09:19

Publisher DOI:

10.3389/fnhum.2017.00542

PubMed ID:

29163115

BORIS DOI:

10.7892/boris.106977

URI:

https://boris.unibe.ch/id/eprint/106977

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