Anodal tDCS Over Wernicke's Area Improves Verbal Memory and Prevents the Interference Effect During Words Learning

• Published in: Neuropsychology Vol. 33; no. 2; pp. 263 - 274
• Main Authors: Rivera-Urbina, G. Nathzidy, Mendez Joya, María Fernanda, Nitsche, Michael A., Molero-Chamizo, Andrés
• Format: Journal Article
• Language: English
• Published: United States American Psychological Association 01-02-2019
• Subjects: Adolescent; Adult; Comprehension - physiology; Female; Human; Humans; Interference (Learning); Language; Learning; Male; Mental Recall - physiology; Stimulation; Transcranial Direct Current Stimulation; Verbal Comprehension; Verbal Learning; Verbal Learning - physiology; Verbal Memory; Vocabulary; Wernicke Area - physiology; Wernicke Encephalopathy; Words (Phonetic Units); Young Adult; verbal memory; anodal tDCS; Wernicke's area; stimulation intensities; verbal learning
• ISSN: 0894-4105; 1931-1559
• DOI: 10.1037/neu0000514

Background: Wernicke's area is a key component of the cortical language network, and it is functionally related to the comprehension of oral and written language. In addition to its main role in the perception of language, some other functions related to verbal learning also seem to involve the activity of this cortical region. It is unknown whether different degrees of neuromodulation on this area determine its effect on word learning. Objective: We aimed to analyze the influence of the application of anodal transcranial DC stimulation (tDCS) over Wernicke's area at two different intensities on word learning. Method: We compared the effect of anodal tDCS at an intensity of 0.5 mA and 1.5 mA with sham tDCS, separately in different groups, on performance in a word learning and recall task. Results: The results show that 1.5 mA anodal tDCS improved performance. The number of words learned in this condition was higher compared with stimulation at 0.5 mA current strength and sham stimulation. Furthermore, stimulation with 1.5 mA specifically prevented the interference effect over word learning, compared to the other two tDCS conditions. Conclusions: These results show an intensity-dependent effect of anodal tDCS on verbal memory formation. These findings are discussed in the context of the various functions of Wernicke's area and the ability of tDCS to modulate the activity and functionality of this cortical area at different intensities.
General Scientific Summary
Performance in a verbal memory task is improved by anodal transcranial DC stimulation (tDCS) applied over Wernicke's area. This effect seems to be intensity-dependent as 0.5 mA tDCS did not affect verbal memory, compared with an improvement effect induced by 1.5 mA tDCS. In addition to the sensory function classically attributed to Wernicke's area, this cortical region may also be involved in verbal memory processes.