Anodal Transcranial Direct Current Stimulation Induces High Gamma-Band Activity in the Left Dorsolateral Prefrontal Cortex During a Working Memory Task: A Double-Blind, Randomized, Crossover Study
Transcranial direct current stimulation (tDCS) has been shown to have mixed effects on working memory (WM) capacity in healthy individuals. Different stimulation paradigms may account for these discrepancies, with certain features being favored. To determine the effect in the context of anodal tDCS,...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2019-04-01
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| Series: | Frontiers in Human Neuroscience |
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| Online Access: | https://www.frontiersin.org/article/10.3389/fnhum.2019.00136/full |
| _version_ | 1828765644333514752 |
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| author | Takashi Ikeda Tetsuya Takahashi Tetsuya Takahashi Hirotoshi Hiraishi Daisuke N. Saito Mitsuru Kikuchi Mitsuru Kikuchi |
| author_facet | Takashi Ikeda Tetsuya Takahashi Tetsuya Takahashi Hirotoshi Hiraishi Daisuke N. Saito Mitsuru Kikuchi Mitsuru Kikuchi |
| author_sort | Takashi Ikeda |
| collection | DOAJ |
| description | Transcranial direct current stimulation (tDCS) has been shown to have mixed effects on working memory (WM) capacity in healthy individuals. Different stimulation paradigms may account for these discrepancies, with certain features being favored. To determine the effect in the context of anodal tDCS, we investigated whether anodal tDCS induced cortical oscillatory changes during a WM task. Specifically, we tested whether anodal offline tDCS over the left prefrontal cortex (PFC) enhances WM capacity by modulating the oscillatory activity in the left dorsolateral PFC (DLPFC) using magnetoencephalography (MEG). This study employed a double-blind, randomized, crossover design, in which 24 healthy right-handed participants conducted MEG recordings during a 3-back task after administration of 2 mA tDCS or sham stimulation as a placebo. Our results showed that the effect of tDCS did not appear in the behavioral indices—WM accuracy (d′) or reaction time (RT). From the results of the time-frequency analysis, significant event-related synchronization (ERS) in the high-gamma band (82–84 Hz) of the left DLPFC was found under the tDCS condition; however, ERS was not correlated with WM capacity. Furthermore, we calculated the modulation index (MI), which indicates the strength of phase-amplitude coupling (PAC). tDCS significantly decreased MI of the left DLPFC, representing the theta-gamma PAC during the n-back task using color names as verbal stimuli. Our results suggest that although tDCS increased the gamma-band oscillation indicating greater neural activity in the left DLPFC, it did not lead to an improvement of WM capacity; this may be due to the inability of gamma-band oscillation to couple with the task-induced theta wave. WM capacity might not increase unless theta-gamma PAC is not enhanced by tDCS. |
| first_indexed | 2024-12-11T06:51:55Z |
| format | Article |
| id | doaj.art-b503628fb0f4473494c1ac9fd5146467 |
| institution | Directory Open Access Journal |
| issn | 1662-5161 |
| language | English |
| last_indexed | 2024-12-11T06:51:55Z |
| publishDate | 2019-04-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Human Neuroscience |
| spelling | doaj.art-b503628fb0f4473494c1ac9fd51464672022-12-22T01:16:54ZengFrontiers Media S.A.Frontiers in Human Neuroscience1662-51612019-04-011310.3389/fnhum.2019.00136445843Anodal Transcranial Direct Current Stimulation Induces High Gamma-Band Activity in the Left Dorsolateral Prefrontal Cortex During a Working Memory Task: A Double-Blind, Randomized, Crossover StudyTakashi Ikeda0Tetsuya Takahashi1Tetsuya Takahashi2Hirotoshi Hiraishi3Daisuke N. Saito4Mitsuru Kikuchi5Mitsuru Kikuchi6Research Center for Child Mental Development, Kanazawa University, Kanazawa, JapanResearch Center for Child Mental Development, Kanazawa University, Kanazawa, JapanDepartment of Neuropsychiatry, University of Fukui, Fukui, JapanDepartment of Biofunctional Imaging, Preeminent Medical Photonics Education & Research Center, Hamamatsu University School of Medicine, Hamamatsu, JapanResearch Center for Child Mental Development, Kanazawa University, Kanazawa, JapanResearch Center for Child Mental Development, Kanazawa University, Kanazawa, JapanDepartment of Psychiatry and Neurobiology, Graduate School of Medical Science, Kanazawa University, Kanazawa, JapanTranscranial direct current stimulation (tDCS) has been shown to have mixed effects on working memory (WM) capacity in healthy individuals. Different stimulation paradigms may account for these discrepancies, with certain features being favored. To determine the effect in the context of anodal tDCS, we investigated whether anodal tDCS induced cortical oscillatory changes during a WM task. Specifically, we tested whether anodal offline tDCS over the left prefrontal cortex (PFC) enhances WM capacity by modulating the oscillatory activity in the left dorsolateral PFC (DLPFC) using magnetoencephalography (MEG). This study employed a double-blind, randomized, crossover design, in which 24 healthy right-handed participants conducted MEG recordings during a 3-back task after administration of 2 mA tDCS or sham stimulation as a placebo. Our results showed that the effect of tDCS did not appear in the behavioral indices—WM accuracy (d′) or reaction time (RT). From the results of the time-frequency analysis, significant event-related synchronization (ERS) in the high-gamma band (82–84 Hz) of the left DLPFC was found under the tDCS condition; however, ERS was not correlated with WM capacity. Furthermore, we calculated the modulation index (MI), which indicates the strength of phase-amplitude coupling (PAC). tDCS significantly decreased MI of the left DLPFC, representing the theta-gamma PAC during the n-back task using color names as verbal stimuli. Our results suggest that although tDCS increased the gamma-band oscillation indicating greater neural activity in the left DLPFC, it did not lead to an improvement of WM capacity; this may be due to the inability of gamma-band oscillation to couple with the task-induced theta wave. WM capacity might not increase unless theta-gamma PAC is not enhanced by tDCS.https://www.frontiersin.org/article/10.3389/fnhum.2019.00136/fulltDCSworking memoryDLPFCMEGphase-amplitude couplingn-back task |
| spellingShingle | Takashi Ikeda Tetsuya Takahashi Tetsuya Takahashi Hirotoshi Hiraishi Daisuke N. Saito Mitsuru Kikuchi Mitsuru Kikuchi Anodal Transcranial Direct Current Stimulation Induces High Gamma-Band Activity in the Left Dorsolateral Prefrontal Cortex During a Working Memory Task: A Double-Blind, Randomized, Crossover Study Frontiers in Human Neuroscience tDCS working memory DLPFC MEG phase-amplitude coupling n-back task |
| title | Anodal Transcranial Direct Current Stimulation Induces High Gamma-Band Activity in the Left Dorsolateral Prefrontal Cortex During a Working Memory Task: A Double-Blind, Randomized, Crossover Study |
| title_full | Anodal Transcranial Direct Current Stimulation Induces High Gamma-Band Activity in the Left Dorsolateral Prefrontal Cortex During a Working Memory Task: A Double-Blind, Randomized, Crossover Study |
| title_fullStr | Anodal Transcranial Direct Current Stimulation Induces High Gamma-Band Activity in the Left Dorsolateral Prefrontal Cortex During a Working Memory Task: A Double-Blind, Randomized, Crossover Study |
| title_full_unstemmed | Anodal Transcranial Direct Current Stimulation Induces High Gamma-Band Activity in the Left Dorsolateral Prefrontal Cortex During a Working Memory Task: A Double-Blind, Randomized, Crossover Study |
| title_short | Anodal Transcranial Direct Current Stimulation Induces High Gamma-Band Activity in the Left Dorsolateral Prefrontal Cortex During a Working Memory Task: A Double-Blind, Randomized, Crossover Study |
| title_sort | anodal transcranial direct current stimulation induces high gamma band activity in the left dorsolateral prefrontal cortex during a working memory task a double blind randomized crossover study |
| topic | tDCS working memory DLPFC MEG phase-amplitude coupling n-back task |
| url | https://www.frontiersin.org/article/10.3389/fnhum.2019.00136/full |
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