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Tseng P, Cheng T. Causal prominence for neuroscience. Nat Rev Neurosci 2024:10.1038/s41583-024-00838-6. [PMID: 38902513 DOI: 10.1038/s41583-024-00838-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/22/2024]
Affiliation(s)
- Philip Tseng
- Department of Psychology, National Taiwan University, Taipei, Taiwan.
| | - Tony Cheng
- Waseda Institute for Advanced Study, Waseda University, Tokyo, Japan
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2
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Vergallito A, Varoli E, Pisoni A, Mattavelli G, Del Mauro L, Feroldi S, Vallar G, Romero Lauro LJ. State-dependent effectiveness of cathodal transcranial direct current stimulation on cortical excitability. Neuroimage 2023; 277:120242. [PMID: 37348625 DOI: 10.1016/j.neuroimage.2023.120242] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 06/09/2023] [Accepted: 06/20/2023] [Indexed: 06/24/2023] Open
Abstract
The extensive use of transcranial direct current stimulation (tDCS) in experimental and clinical settings does not correspond to an in-depth understanding of its underlying neurophysiological mechanisms. In previous studies, we employed an integrated system of Transcranial Magnetic Stimulation and Electroencephalography (TMS-EEG) to track the effect of tDCS on cortical excitability. At rest, anodal tDCS (a-tDCS) over the right Posterior Parietal Cortex (rPPC) elicits a widespread increase in cortical excitability. In contrast, cathodal tDCS (c-tDCS) fails to modulate cortical excitability, being indistinguishable from sham stimulation. Here we investigated whether an endogenous task-induced activation during stimulation might change this pattern, improving c-tDCS effectiveness in modulating cortical excitability. In Experiment 1, we tested whether performance in a Visuospatial Working Memory Task (VWMT) and a modified Posner Cueing Task (mPCT), involving rPPC, could be modulated by c-tDCS. Thirty-eight participants were involved in a two-session experiment receiving either c-tDCS or sham during tasks execution. In Experiment 2, we recruited sixteen novel participants who performed the same paradigm but underwent TMS-EEG recordings pre- and 10 min post- sham stimulation and c-tDCS. Behavioral results showed that c-tDCS significantly modulated mPCT performance compared to sham. At a neurophysiological level, c-tDCS significantly reduced cortical excitability in a frontoparietal network likely involved in task execution. Taken together, our results provide evidence of the state dependence of c-tDCS in modulating cortical excitability effectively. The conceptual and applicative implications are discussed.
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Affiliation(s)
- Alessandra Vergallito
- Department of Psychology, University of Milano-Bicocca, Milano, Italy; NeuroMi, Milan Center for Neuroscience, Milano, Italy.
| | - Erica Varoli
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
| | - Alberto Pisoni
- Department of Psychology, University of Milano-Bicocca, Milano, Italy; NeuroMi, Milan Center for Neuroscience, Milano, Italy
| | - Giulia Mattavelli
- IUSS Cognitive Neuroscience (ICON) Center, Scuola Universitaria Superiore IUSS, Pavia, Italy; Istituti Clinici Scientifici Maugeri IRCCS, Cognitive Neuroscience Laboratory of Pavia Institute, 27100, Italy
| | - Lilia Del Mauro
- Department of Psychology, University of Milano-Bicocca, Milano, Italy
| | - Sarah Feroldi
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
| | - Giuseppe Vallar
- Department of Psychology, University of Milano-Bicocca, Milano, Italy; NeuroMi, Milan Center for Neuroscience, Milano, Italy; MiBTec - Mind and Behavior Technological Center, University of Milano-Bicocca, Milan, Italy
| | - Leonor J Romero Lauro
- Department of Psychology, University of Milano-Bicocca, Milano, Italy; NeuroMi, Milan Center for Neuroscience, Milano, Italy
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3
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Sahu PP, Tseng P. Gamma sensory entrainment for cognitive improvement in neurodegenerative diseases: opportunities and challenges ahead. Front Integr Neurosci 2023; 17:1146687. [PMID: 37138796 PMCID: PMC10149720 DOI: 10.3389/fnint.2023.1146687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 03/27/2023] [Indexed: 05/05/2023] Open
Abstract
Neural oscillations have been categorized into various frequency bands that are mechanistically associated with different cognitive functions. Specifically, the gamma band frequency is widely implicated to be involved in a wide range of cognitive processes. As such, decreased gamma oscillation has been associated with cognitive declines in neurological diseases, such as memory dysfunction in Alzheimer's disease (AD). Recently, studies have attempted to artificially induce gamma oscillations by using 40 Hz sensory entrainment stimulation. These studies reported attenuation of amyloid load, hyper-phosphorylation of tau protein, and improvement in overall cognition in both AD patients and mouse models. In this review, we discuss the advancements in the use of sensory stimulation in animal models of AD and as a therapeutic strategy in AD patients. We also discuss future opportunities, as well as challenges, for using such strategies in other neurodegenerative and neuropsychiatric diseases.
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Affiliation(s)
- Prangya Parimita Sahu
- Graduate Institute of Mind, Brain and Consciousness, Taipei Medical University, Taipei, Taiwan
- Brain and Consciousness Research Center, Shuang Ho Hospital, Taipei Medical University, Taipei, Taiwan
| | - Philip Tseng
- Cross College Elite Program, National Cheng Kung University, Tainan, Taiwan
- Research Center for Mind, Brain and Learning, National Chengchi University, Taipei, Taiwan
- *Correspondence: Philip Tseng,
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4
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Lega C, Cattaneo L, Costantini G. How to Test the Association Between Baseline Performance Level and the Modulatory Effects of Non-Invasive Brain Stimulation Techniques. Front Hum Neurosci 2022; 16:920558. [PMID: 35814951 PMCID: PMC9265211 DOI: 10.3389/fnhum.2022.920558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 06/06/2022] [Indexed: 11/13/2022] Open
Abstract
Behavioral effects of non-invasive brain stimulation techniques (NIBS) can dramatically change as a function of different factors (e.g., stimulation intensity, timing of stimulation). In this framework, lately there has been a growing interest toward the importance of considering the inter-individual differences in baseline performance and how they are related with behavioral NIBS effects. However, assessing how baseline performance level is associated with behavioral effects of brain stimulation techniques raises up crucial methodological issues. How can we test whether the performance at baseline is predictive of the effects of NIBS, when NIBS effects themselves are estimated with reference to baseline performance? In this perspective article, we discuss the limitations connected to widely used strategies for the analysis of the association between baseline value and NIBS effects, and review solutions to properly address this type of question.
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Affiliation(s)
- Carlotta Lega
- Department of Psychology and Milan Center for Neuroscience (NeuroMI), University of Milano-Bicocca, Milan, Italy
- *Correspondence: Carlotta Lega
| | - Luigi Cattaneo
- Center for Mind/Brain Sciences (CIMeC), University of Trento, Trento, Italy
- Centre for Medical Sciences (CISMed), University of Trento, Trento, Italy
| | - Giulio Costantini
- Department of Psychology and Milan Center for Neuroscience (NeuroMI), University of Milano-Bicocca, Milan, Italy
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5
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Inter-Individual Variability in tDCS Effects: A Narrative Review on the Contribution of Stable, Variable, and Contextual Factors. Brain Sci 2022; 12:brainsci12050522. [PMID: 35624908 PMCID: PMC9139102 DOI: 10.3390/brainsci12050522] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Revised: 04/08/2022] [Accepted: 04/14/2022] [Indexed: 01/27/2023] Open
Abstract
Due to its safety, portability, and cheapness, transcranial direct current stimulation (tDCS) use largely increased in research and clinical settings. Despite tDCS’s wide application, previous works pointed out inconsistent and low replicable results, sometimes leading to extreme conclusions about tDCS’s ineffectiveness in modulating behavioral performance across cognitive domains. Traditionally, this variability has been linked to significant differences in the stimulation protocols across studies, including stimulation parameters, target regions, and electrodes montage. Here, we reviewed and discussed evidence of heterogeneity emerging at the intra-study level, namely inter-individual differences that may influence the response to tDCS within each study. This source of variability has been largely neglected by literature, being results mainly analyzed at the group level. Previous research, however, highlighted that only a half—or less—of studies’ participants could be classified as responders, being affected by tDCS in the expected direction. Stable and variable inter-individual differences, such as morphological and genetic features vs. hormonal/exogenous substance consumption, partially account for this heterogeneity. Moreover, variability comes from experiments’ contextual elements, such as participants’ engagement/baseline capacity and individual task difficulty. We concluded that increasing knowledge on inter-dividual differences rather than undermining tDCS effectiveness could enhance protocols’ efficiency and reproducibility.
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6
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Boran E, Hilfiker P, Stieglitz L, Sarnthein J, Klaver P. Persistent neuronal firing in the medial temporal lobe supports performance and workload of visual working memory in humans. Neuroimage 2022; 254:119123. [PMID: 35321857 DOI: 10.1016/j.neuroimage.2022.119123] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Revised: 03/18/2022] [Accepted: 03/19/2022] [Indexed: 11/25/2022] Open
Abstract
The involvement of the medial temporal lobe (MTL) in working memory is controversially discussed. Recent findings suggest that persistent neural firing in the hippocampus during maintenance in verbal working memory is associated with workload. Here, we recorded single neuron firing in 13 epilepsy patients (7 male) while they performed a visual working memory task. The number of coloured squares in the stimulus set determined the workload of the trial. Performance was almost perfect for low workload (1 and 2 squares) and dropped at high workload (4 and 6 squares), suggesting that high workload exceeded working memory capacity. We identified maintenance neurons in MTL neurons that showed persistent firing during the maintenance period. More maintenance neurons were found in the hippocampus for trials with correct compared to incorrect performance. Maintenance neurons increased and decreased firing in the hippocampus and increased firing in the entorhinal cortex for high compared to low workload. Population firing predicted workload particularly during the maintenance period. Prediction accuracy of workload based on single-trial activity during maintenance was strongest for neurons in the entorhinal cortex and hippocampus. The data suggest that persistent neural firing in the MTL reflects a domain-general process of maintenance supporting performance and workload of multiple items in working memory below and beyond working memory capacity. Persistent neural firing during maintenance in the entorhinal cortex may be associated with its preference to process visual-spatial arrays.
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Affiliation(s)
- Ece Boran
- Department of Neurosurgery, University Hospital Zurich (USZ), University of Zurich, 8091 Zurich, Switzerland
| | | | - Lennart Stieglitz
- Department of Neurosurgery, University Hospital Zurich (USZ), University of Zurich, 8091 Zurich, Switzerland
| | - Johannes Sarnthein
- Department of Neurosurgery, University Hospital Zurich (USZ), University of Zurich, 8091 Zurich, Switzerland; Neuroscience Center Zurich, ETH Zurich, 8057 Zurich, Switzerland.
| | - Peter Klaver
- University of Teacher Education in Special Needs, 8050 Zurich, Switzerland; Institute of Psychology, University of Zurich, 8050 Zurich, Switzerland; School of Psychology, University of Surrey, GU2 7XH Guildford, UK.
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7
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Gupta P, Sahu A, Prasad S, Sinha VK, Bakhla AK. Memory changes following adjuvant temporo-parietal repetitive transcranial magnetic stimulation in schizophrenia. Indian J Psychiatry 2021; 63:66-69. [PMID: 34083822 PMCID: PMC8106430 DOI: 10.4103/psychiatry.indianjpsychiatry_532_20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 09/01/2020] [Accepted: 10/23/2020] [Indexed: 12/04/2022] Open
Abstract
OBJECTIVE The use of repetitive transcranial magnetic stimulation (rTMS) in schizophrenia has shown improvement as well as deficits in memory. Though most studies had focused on dorsolateral prefrontal cortex only, but impact of rTMS on cognitive functions remain inconclusive. The need of the study is to assess the impact of rTMS on memory in schizophrenia. MATERIALS AND METHODS Forty right-handed male patients with schizophrenia were included by purposive sampling and rated on Positive and Negative Syndrome Scale (PANSS) before starting the rTMS treatment with the experimental group. Low frequency 1 Hz rTMS including 1200 stimulations were given over temporo-parietal cortex for 20 min as add on to medications. At the end of 10 session treatment (5 days a week for 2 weeks), the patients were re-evaluated. RESULTS A total of 39 patients (20 for experimental group and 19 for control group) with mean age of 29.70 ± 9.05 and 31.26 ± 7.78 years, respectively, shows significant difference to pre- and post-treatment mean PANSS score in positive, negative and general psychopathology domains. The pre- and post-treatment mean Postgraduate Institute Memory Scale Scores with multivariate repeated measures analysis of variance revealed significant improvements in all memory domains (P < 0.01) except remote memory in both experimental and control groups. CONCLUSION RTMS in combination with antipsychotics has shown improvement in psychopathology in patients of schizophrenia without any deterioration of memory.
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Affiliation(s)
- Preeti Gupta
- Department of Clinical Psychology, Central Institute of Psychiatry, Ranchi, Jharkhand, India
| | - Anamika Sahu
- Student Wellness Centre, AIIMS, New Delhi, India
| | - Surjit Prasad
- Department of Psychiatry, Central Institute of Psychiatry, Ranchi, Jharkhand, India
| | - Vinod Kumar Sinha
- Department of Psychiatry, Central Institute of Psychiatry, Ranchi, Jharkhand, India
| | - Ajay Kumar Bakhla
- Department of Psychiatry, Rajendra Institute of Medical Sciences, Ranchi, Jharkhand, India
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8
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Tseng P, Lo YH. Altered EEG Signal Complexity Induced by Hand Proximity: A Multiscale Entropy Approach. Front Neurosci 2020; 14:562132. [PMID: 33132825 PMCID: PMC7578420 DOI: 10.3389/fnins.2020.562132] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 09/18/2020] [Indexed: 11/24/2022] Open
Abstract
Visual short-term memory (VSTM) is an important cognitive function that acts as a temporary storage for visual information. Previous studies have shown that VSTM capacity can be modulated by the location of one’s hands, where hand proximity enhances neural processing and memory of nearby visual stimuli. The present study used traditional event-related potentials (ERP) along with multiscale entropy (MSE) analysis to shed light on the neural mechanism(s) behind such near-hand effect. Participants’ electroencephalogram (EEG) data were recorded as they performed a VSTM task with their hands either proximal or distal to the display. ERP analysis showed altered memory processing in the 400–700 ms time window during memory retrieval period. Importantly, MSE analysis also showed significant EEG difference between hand proximal and distal conditions between scales 10 to 20, and such difference is clustered around the right parietal cortex – a region that is involved in VSTM processing and bimodal hand-eye integration. The implications of higher MSE time scale in the parietal cortex are discussed in the context of signal complexity and its possible relation to cognitive processing. To our knowledge, this study provides the first investigation using MSE to characterize the temporal characteristics and signal complexity behind the effect of hand proximity.
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Affiliation(s)
- Philip Tseng
- Graduate Institute of Mind, Brain and Consciousness, Taipei Medical University, Taipei, Taiwan.,Brain and Consciousness Research Center, TMU-Shuang Ho Hospital, New Taipei City, Taiwan.,Psychiatric Research Center, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
| | - Yu-Hui Lo
- Brain and Consciousness Research Center, TMU-Shuang Ho Hospital, New Taipei City, Taiwan
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9
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Zhao C, Woodman GF. Converging Evidence That Neural Plasticity Underlies Transcranial Direct-Current Stimulation. J Cogn Neurosci 2020; 33:146-157. [PMID: 33054552 DOI: 10.1162/jocn_a_01639] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
It is not definitely known how direct-current stimulation causes its long-lasting effects. Here, we tested the hypothesis that the long time course of transcranial direct-current stimulation (tDCS) is because of the electrical field increasing the plasticity of the brain tissue. If this is the case, then we should see tDCS effects when humans need to encode information into long-term memory, but not at other times. We tested this hypothesis by delivering tDCS to the ventral visual stream of human participants during different tasks (i.e., recognition memory vs. visual search) and at different times during a memory task. We found that tDCS improved memory encoding, and the neural correlates thereof, but not retrieval. We also found that tDCS did not change the efficiency of information processing during visual search for a certain target object, a task that does not require the formation of new connections in the brain but instead relies on attention and object recognition mechanisms. Thus, our findings support the hypothesis that direct-current stimulation modulates brain activity by changing the underlying plasticity of the tissue.
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10
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Zhao D, Zhou YD, Bodner M, Ku Y. The Causal Role of the Prefrontal Cortex and Somatosensory Cortex in Tactile Working Memory. Cereb Cortex 2019; 28:3468-3477. [PMID: 28968894 DOI: 10.1093/cercor/bhx213] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2017] [Indexed: 12/31/2022] Open
Abstract
In the present study, we searched for causal evidence linking activity in the bilateral primary somatosensory cortex (SI), posterior parietal cortex (PPC), and prefrontal cortex (PFC) with behavioral performance in vibrotactile working memory. Participants performed a vibrotactile delayed matching-to-sample task, while single-pulse transcranial magnetic stimulation (sp-TMS) was applied over these cortical areas at 100, 200, 300, 600, 1600, and 1900 ms after the onset of vibrotactile stimulation (200 ms duration). In our experiments, sp-TMS over the contralateral SI at the early delay (100 and 200 ms) deteriorated the accuracy of task performance, and over the ipsilateral SI at the late delay (1600 and 1900 ms) also induced such deteriorating effects. Furthermore, deteriorating effects caused by sp-TMS over the contralateral DLPFC at the same maintenance stage (1600 ms) were correlated with the effects caused by sp-TMS over the ipsilateral SI, indicating that information retained in the ipsilateral SI during the late delay may be associated with the DLPFC. Taken together, these results suggest that both the contralateral and ipsilateral SIs are involved in tactile WM, and the contralateral DLPFC bridges the contralateral SI and ipsilateral SI for goal-directed action.
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Affiliation(s)
- Di Zhao
- The Key Lab of Brain Functional Genomics, MOE & STCSM, School of Psychology and Cognitive Science, East China Normal University, Shanghai, China
| | - Yong-Di Zhou
- NYU-ECNU Institute of Brain and Cognitive Science, NYU Shanghai and Collaborative Innovation Center for Brain Science, Shanghai, China.,Krieger Mind/Brain Institute, Department of Neurosurgery, Johns Hopkins University, Baltimore, MD, USA
| | | | - Yixuan Ku
- The Key Lab of Brain Functional Genomics, MOE & STCSM, School of Psychology and Cognitive Science, East China Normal University, Shanghai, China.,NYU-ECNU Institute of Brain and Cognitive Science, NYU Shanghai and Collaborative Innovation Center for Brain Science, Shanghai, China
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11
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Hilbert S, McAssey M, Bühner M, Schwaferts P, Gruber M, Goerigk S, Taylor PCJ. Right hemisphere occipital rTMS impairs working memory in visualizers but not in verbalizers. Sci Rep 2019; 9:6307. [PMID: 31004125 PMCID: PMC6474855 DOI: 10.1038/s41598-019-42733-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 04/04/2019] [Indexed: 01/26/2023] Open
Abstract
Distinguishing between verbal and visual working memory processes is complicated by the fact that the strategy used is hard to control or even assess. Many stimuli used in working memory tasks can be processed via verbal or visual coding, such as the digits in the digit span backwards task (DSB). The present study used repetitive transcranial magnetic stimulation (rTMS) to examine the use of visual processing strategies in the DSB. A total of 47 German university students took part in the study, 23 spontaneously using a verbal processing strategy and 24 using a visual strategy. After rTMS to the right occipital cortex, visualizers showed a significantly stronger mean performance decrease compared to verbalizers. The results indicate that the visual cortex is more critical for visualizers compared to verbalizers in the DSB task. Furthermore, the favored processing modality seems to be determined by the preference for a cognitive strategy rather than the presentation modality, and people are aware of the applied strategy. These findings provide insight into inter-individual differences in working memory processing and yield important implications for laboratory studies as well as clinical practice: the stimulus does not necessarily determine the processing and the participant can be aware of that.
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Affiliation(s)
- Sven Hilbert
- Faculty of Psychology, Educational Science, and Sport Science, University of Regensburg, Universitätsstraße 31, 93053, Regensburg, Germany.
| | - Michaela McAssey
- Department of Neurology, University Hospital, LMU Munich, Munich, Germany
- Graduate School of Systemic Neuroscience, Research Training Group 2175, Ludwig-Maximilians-University, Leopoldstraße 13, 80802, München, Germany
| | - Markus Bühner
- Department of Psychology, Psychological Methods and Assessment, LMU Munich, Leopoldstraße 13, 80802, München, Germany
| | - Patrick Schwaferts
- Institute of Statistics, Methodological Foundations of Statistics and its Applications, Ludwigstraße 33, 80539, München, Germany
| | - Monika Gruber
- Department of Psychology, Psychological Methods and Assessment, LMU Munich, Leopoldstraße 13, 80802, München, Germany
| | - Stephan Goerigk
- Department of Psychiatry and Psychotherapy, Ludwig-Maximilians-University, Nußbaumstraße 7, 80336, Munich, Germany
- Hochschule Fresenius, University of Applied Sciences, Infanteriestraße 11A, 80797, Munich, Germany
| | - Paul Christopher John Taylor
- Department of Neurology, University Hospital, LMU Munich, Munich, Germany
- German Center for Vertigo and Balance Disorders, University Hospital, LMU Munich, Munich, Germany
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12
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Wang CH, Moreau D, Yang CT, Tsai YY, Lin JT, Liang WK, Tsai CL. Aerobic exercise modulates transfer and brain signal complexity following cognitive training. Biol Psychol 2019; 144:85-98. [PMID: 30943426 DOI: 10.1016/j.biopsycho.2019.03.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 02/21/2019] [Accepted: 03/22/2019] [Indexed: 12/11/2022]
Abstract
Although recent evidence has demonstrated the potent effect of physical exercise to increase the efficacy of cognitive training, the neural mechanisms underlying this causal relationship remain unclear. Here, we used multiscale entropy (MSE) of electroencephalography (EEG)-a measure of brain signal complexity-to address this issue. Young males were randomly assigned to either a 20-day dual n-back training following aerobic exercise or the same training regimen following a reading. A feature binding working memory task with concurrent EEG recording was used to test for transfer effects. Although results revealed weak-to-moderate evidence for exercise-induced facilitation on cognitive training, the combination of cognitive training with exercise resulted in greater transfer gains on conditions involving greater attentional demanding, together with greater increases in cognitive modulation on MSE, compared with the reading condition. Overall, our findings suggest that the addition of antecedent physical exercise to brain training regimen could enable wider, more robust improvements.
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Affiliation(s)
- Chun-Hao Wang
- Institute of Physical Education, Health & Leisure Studies, National Cheng Kung University, No. 1, University Road, Tainan City, Taiwan
| | - David Moreau
- School of Psychology and Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - Cheng-Ta Yang
- Department of Psychology, National Cheng Kung University, Social Sciences Building, No. 1, University Road, East District, Tainan City 701, Taiwan; Institute of Allied Health Sciences, National Cheng Kung University, No.1, University Road, Tainan City, Tainan
| | - Yun-Yen Tsai
- Institute of Physical Education, Health & Leisure Studies, National Cheng Kung University, No. 1, University Road, Tainan City, Taiwan
| | - Jui-Tang Lin
- Institute of Physical Education, Health & Leisure Studies, National Cheng Kung University, No. 1, University Road, Tainan City, Taiwan
| | - Wei-Kuang Liang
- Institute of Cognitive Neuroscience, National Central University, Jhongli 320, Taiwan.
| | - Chia-Liang Tsai
- Institute of Physical Education, Health & Leisure Studies, National Cheng Kung University, No. 1, University Road, Tainan City, Taiwan.
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13
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Tseng P, Wang MC, Lo YH, Juan CH. Anodal and Cathodal tDCS Over the Right Frontal Eye Fields Impacts Spatial Probability Processing Differently in Pro- and Anti-saccades. Front Neurosci 2018; 12:421. [PMID: 29997471 PMCID: PMC6030360 DOI: 10.3389/fnins.2018.00421] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Accepted: 06/04/2018] [Indexed: 11/17/2022] Open
Abstract
Learning regularities that exist in the environment can help the visual system achieve optimal efficiency while reducing computational burden. Using a pro- and anti-saccade task, studies have shown that probabilistic information regarding spatial locations can be a strong modulator of frontal eye fields (FEF) activities and consequently alter saccadic behavior. One recent study has also shown that FEF activities can be modulated by transcranial direct current stimulation, where anodal tDCS facilitated prosaccades but cathodal tDCS prolonged antisaccades. These studies together suggest that location probability and tDCS can both alter FEF activities and oculomotor performance, yet how these two modulators interact with each other remains unclear. In this study, we applied anodal or cathodal tDCS over right FEF, and participants performed an interleaved pro- and anti-saccade task. Location probability was manipulated in prosaccade trials but not antisaccade trials. We observed that anodal tDCS over rFEF facilitated prosaccdes toward low-probability locations but not to high-probability locations; whereas cathodal tDCS facilitated antisaccades away from the high-probability location (i.e., same location as the low-probability locations in prosaccades). These observed effects were specific to rFEF as tDCS over the SEF in a separate control experiment did not yield similar patterns. These effects were also more pronounced in low-performers who had slower saccade reaction time. Together, we conclude that (1) the overlapping spatial endpoint between prosaccades (i.e., toward low-probability location) and antisaccades (i.e., away from high-probability location) possibly suggest an endpoint-selective mechanism within right FEF, (2) anodal tDCS and location probability cannot be combined to produce a bigger facilitative effect, and (3) anodal rFEF tDCS works best on low-performers who had slower saccade reaction time. These observations are consistent with the homeostasis account of tDCS effect and FEF functioning.
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Affiliation(s)
- Philip Tseng
- Graduate Institute of Humanities in Medicine, Taipei Medical University, Taipei, Taiwan.,Research Center of Brain and Consciousness, Taipei Medical University, Taipei, Taiwan.,Shuang-Ho Hospital, Taipei Medical University, Taipei, Taiwan
| | - Mu-Chen Wang
- Institute of Cognitive Neuroscience, National Central University, Taoyuan, Taiwan
| | - Yu-Hui Lo
- Research Center of Brain and Consciousness, Taipei Medical University, Taipei, Taiwan
| | - Chi-Hung Juan
- Institute of Cognitive Neuroscience, National Central University, Taoyuan, Taiwan.,Brain Research Center, National Central University, Taoyuan, Taiwan
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14
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Silvanto J, Bona S, Marelli M, Cattaneo Z. On the Mechanisms of Transcranial Magnetic Stimulation (TMS): How Brain State and Baseline Performance Level Determine Behavioral Effects of TMS. Front Psychol 2018; 9:741. [PMID: 29867693 PMCID: PMC5966578 DOI: 10.3389/fpsyg.2018.00741] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 04/27/2018] [Indexed: 11/13/2022] Open
Abstract
The behavioral effects of Transcranial Magnetic Stimulation (TMS) can change qualitatively when stimulation is preceded by initial state manipulations such as priming or adaptation. In addition, baseline performance level of the participant has been shown to play a role in modulating the impact of TMS. Here we examined the link between these two factors. This was done using data from a previous study using a TMS-priming paradigm, in which, at group level, TMS selectively facilitated targets incongruent with the prime while having no statistically significant effects on other prime-target congruencies. Correlation and linear mixed-effects analyses indicated that, for all prime-target congruencies, a significant linear relationship between baseline performance and the magnitude of the induced TMS effect was present: low levels of baseline performance were associated with TMS-induced facilitations and high baseline performance with impairments. Thus as performance level increased, TMS effects turned from facilitation to impairment. The key finding was that priming shifted the transition from facilitatory to disruptive effects for targets incongruent with the prime, such that TMS-induced facilitations were obtained until a higher level of performance than for other prime-target congruencies. Given that brain state manipulations such as priming operate via modulations of neural excitability, this result is consistent with the view that neural excitability, coupled with non-linear neural effects, underlie behavioral effects of TMS.
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Affiliation(s)
- Juha Silvanto
- Department of Psychology, Faculty of Science and Technology, University of Westminster, London, United Kingdom
| | - Silvia Bona
- Department of Psychology, University of Milano-Bicocca, Milan, Italy
| | - Marco Marelli
- Department of Psychology, University of Milano-Bicocca, Milan, Italy
| | - Zaira Cattaneo
- Department of Psychology, University of Milano-Bicocca, Milan, Italy.,National Scientific Neurological Institute (IRCCS), Mondino Foundation, Pavia, Italy
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15
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Arciniega H, Gözenman F, Jones KT, Stephens JA, Berryhill ME. Frontoparietal tDCS Benefits Visual Working Memory in Older Adults With Low Working Memory Capacity. Front Aging Neurosci 2018; 10:57. [PMID: 29593522 PMCID: PMC5859363 DOI: 10.3389/fnagi.2018.00057] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 02/20/2018] [Indexed: 01/09/2023] Open
Abstract
Working memory (WM) permits maintenance of information over brief delays and is an essential executive function. Unfortunately, WM is subject to age-related decline. Some evidence supports the use of transcranial direct current stimulation (tDCS) to improve visual WM. A gap in knowledge is an understanding of the mechanism characterizing these tDCS linked effects. To address this gap, we compared the effects of two tDCS montages designed on visual working memory (VWM) performance. The bifrontal montage was designed to stimulate the heightened bilateral frontal activity observed in aging adults. The unilateral frontoparietal montage was designed to stimulate activation patterns observed in young adults. Participants completed three sessions (bilateral frontal, right frontoparietal, sham) of anodal tDCS (20 min, 2 mA). During stimulation, participants performed a visual long-term memory (LTM) control task and a visual WM task. There was no effect of tDCS on the LTM task. Participants receiving right unilateral tDCS showed a WM benefit. This pattern was most robust in older adults with low WM capacity. To address the concern that the key difference between the two tDCS montages could be tDCS over the posterior parietal cortex (PPC), we included new analyses from a previous study applying tDCS targeting the PPC paired with a recognition VWM task. No significant main effects were found. A subsequent experiment in young adults found no significant effect of either tDCS montage on either task. These data indicate that tDCS montage, age and WM capacity should be considered when designing tDCS protocols. We interpret these findings as suggestive that protocols designed to restore more youthful patterns of brain activity are superior to those that compensate for age-related changes.
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Affiliation(s)
- Hector Arciniega
- Memory and Brain Laboratory, Department of Psychology, Program in Cognitive and Brain Sciences, and Integrative Neuroscience, University of Nevada, Reno, NV, United States
| | - Filiz Gözenman
- Department of Psychology, Yaşar University, İzmir, Turkey
| | - Kevin T. Jones
- Department of Psychology, Colorado State University, Fort Collins, CO, United States
| | - Jaclyn A. Stephens
- Department of Occupational Therapy, Colorado State University, Fort Collins, CO, United States
| | - Marian E. Berryhill
- Memory and Brain Laboratory, Department of Psychology, Program in Cognitive and Brain Sciences, and Integrative Neuroscience, University of Nevada, Reno, NV, United States
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16
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Lukasik KM, Lehtonen M, Salmi J, Meinzer M, Joutsa J, Laine M. No Effects of Stimulating the Left Ventrolateral Prefrontal Cortex with tDCS on Verbal Working Memory Updating. Front Neurosci 2018; 11:738. [PMID: 29379410 PMCID: PMC5770813 DOI: 10.3389/fnins.2017.00738] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 12/18/2017] [Indexed: 01/01/2023] Open
Abstract
The effects of transcranial direct current stimulation (tDCS) on dorsolateral prefrontal cortex functions, such as working memory (WM), have been examined in a number of studies. However, much less is known about the behavioral effects of tDCS over other important WM-related brain regions, such as the ventrolateral prefrontal cortex (VLPFC). In a counterbalanced within-subjects design with 33 young healthy participants, we examined whether online and offline single-session tDCS over VLPFC affects WM updating performance as measured by a digit 3-back task. We compared three conditions: anodal, cathodal and sham. We observed no significant tDCS effects on participants' accuracy or reaction times during or after the stimulation. Neither did we find any differences between anodal and cathodal stimulation. Largely similar results were obtained when comparing subgroups of high- and low-performing participants. Possible reasons for the lack of effects, including individual differences in responsiveness to tDCS, features of montage, task and sample characteristics, and the role of VLPFC in WM, are discussed.
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Affiliation(s)
| | - Minna Lehtonen
- Department of Psychology, Abo Akademi University, Turku, Finland.,Department of Psychology and Logopedics, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Juha Salmi
- Department of Psychology, Abo Akademi University, Turku, Finland.,Department of Psychology and Logopedics, Faculty of Medicine, University of Helsinki, Helsinki, Finland.,Department of Psychology, University of Turku, Turku, Finland
| | - Marcus Meinzer
- Centre for Clinical Research, The University of Queensland, Brisbane, QLD, Australia
| | - Juho Joutsa
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, United States.,Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, United States.,Department of Neurology, University of Turku, Turku, Finland
| | - Matti Laine
- Department of Psychology, Abo Akademi University, Turku, Finland.,Turku Brain and Mind Center, University of Turku, Turku, Finland
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17
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Tseng P, Iu KC, Juan CH. The critical role of phase difference in theta oscillation between bilateral parietal cortices for visuospatial working memory. Sci Rep 2018; 8:349. [PMID: 29321584 PMCID: PMC5762658 DOI: 10.1038/s41598-017-18449-w] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 12/12/2017] [Indexed: 11/09/2022] Open
Abstract
Visual working memory (VWM) refers to people's ability to maintain and manipulate visual information on line. Its capacity varies between individuals, and neuroimaging studies have suggested a link between one's VWM capacity and theta power in the parietal cortex. However, it is unclear how the parietal cortices communicate with each other in order to support VWM processing. In two experiments we employed transcranial alternate current stimulation (tACS) to use frequency-specific (6 Hz) alternating current to modulate theta oscillation between the left and right parietal cortex with either in-phase (0° difference, Exp 1), anti-phase (180° difference, Exp 2), or sham sinusoidal current stimulation. In Experiment 1, in-phase theta tACS induced an improved VWM performance, but only in low-performers, whereas high-performers suffered a marginally-significant VWM impairment. In Experiment 2, anti-phase theta tACS did not help the low-performers, but significantly impaired high-performers' VWM capacity. These results not only provide causal evidence for theta oscillation in VWM processing, they also highlight the intricate interaction between tACS and individual differences-where the same protocol that enhances low-performers' VWM can backfire for the high-performers. We propose that signal complexity via coherent timing and phase synchronization within the bilateral parietal network is crucial for successful VWM functioning.
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Affiliation(s)
- Philip Tseng
- Graduate Institute of Humanities in Medicine, Taipei Medical University, Taipei City, Taiwan.
- TMU - Research Center of Brain and Consciousness, Taipei Medical University, Taipei City, Taiwan.
- Shuang-Ho Hospital, Taipei Medical University, New Taipei City, Taiwan.
| | - Kai-Chi Iu
- Institute of Cognitive Neuroscience, National Central University, Taoyuan City, Taiwan
| | - Chi-Hung Juan
- Institute of Cognitive Neuroscience, National Central University, Taoyuan City, Taiwan
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18
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Ellison A, Ball KL, Lane AR. The Behavioral Effects of tDCS on Visual Search Performance Are Not Influenced by the Location of the Reference Electrode. Front Neurosci 2017; 11:520. [PMID: 28983233 PMCID: PMC5613168 DOI: 10.3389/fnins.2017.00520] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 09/04/2017] [Indexed: 11/17/2022] Open
Abstract
We investigated the role of reference electrode placement (ipsilateral v contralateral frontal pole) on conjunction visual search task performance when the transcranial direct current stimulation (tDCS) cathode is placed over right posterior parietal cortex (rPPC) and over right frontal eye fields (rFEF), both of which have been shown to be causally involved in the processing of this task using TMS. This resulted in four experimental manipulations in which sham tDCS was applied in week one followed by active tDCS the following week. Another group received sham stimulation in both sessions to investigate practice effects over 1 week in this task. Results show that there is no difference between effects seen when the anode is placed ipsi or contralaterally. Cathodal stimulation of rPPC increased search times straight after stimulation similarly for ipsi and contralateral references. This finding does not extend to rFEF stimulation. However, for both sites and both montages, practice effects as seen in the sham/sham condition were negated. This can be taken as evidence that for this task, reference placement on either frontal pole is not important, but also that care needs to be taken when contextualizing tDCS “effects” that may not be immediately apparent particularly in between-participant designs.
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Affiliation(s)
- Amanda Ellison
- Cognitive Neuroscience Research Unit, Department of Psychology, Durham UniversityDurham, United Kingdom.,Wolfson Research Institute for Health and Wellbeing, Durham UniversityDurham, United Kingdom
| | - Keira L Ball
- Cognitive Neuroscience Research Unit, Department of Psychology, Durham UniversityDurham, United Kingdom.,Wolfson Research Institute for Health and Wellbeing, Durham UniversityDurham, United Kingdom
| | - Alison R Lane
- Cognitive Neuroscience Research Unit, Department of Psychology, Durham UniversityDurham, United Kingdom.,Wolfson Research Institute for Health and Wellbeing, Durham UniversityDurham, United Kingdom
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