1
|
Chuderski A, Chinta SR. Transcranial alternating current stimulation barely enhances working memory in healthy adults: A meta-analysis. Brain Res 2024; 1839:149022. [PMID: 38801916 DOI: 10.1016/j.brainres.2024.149022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 05/20/2024] [Accepted: 05/23/2024] [Indexed: 05/29/2024]
Abstract
Working memory (WM) is a pivotal neural mechanism for cognitive function and ability. Transcranial alternating current stimulation (tACS) was used to improve WM by entraining key brain rhythms. We submitted to meta-analysis 143 effects of tACS on WM performance, found in 42 reports published between 2014 and 2023, encompassing a total of 1386 healthy adults stimulated. The overall effect size of 134 interventions intended to improve WM equaled Hedges' g = 0.076 [0.039, 0.113]. However, after correcting for a significant publication bias this effect size dropped to zero. By contrast, 9 interventions distorting the brain synchronization using antiphase tACS reliably decreased WM performance, with Hedges' g = -0.266, [-0.458, -0.074]. Individuating the targeted frequency band was the only reliable moderator. The disparity between our null outcome and moderately positive tACS effects estimated by previous meta-analyses resulted from our inclusion of the most recent studies mostly reporting negligible effects. Our results suggest that current tACS protocols barely enhance WM in healthy adults. More research is needed to develop effective methods for WM stimulation.
Collapse
|
2
|
Sengupta A, Banerjee S, Ganesh S, Grover S, Sridharan D. The right posterior parietal cortex mediates spatial reorienting of attentional choice bias. Nat Commun 2024; 15:6938. [PMID: 39138185 PMCID: PMC11322534 DOI: 10.1038/s41467-024-51283-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 08/02/2024] [Indexed: 08/15/2024] Open
Abstract
Attention facilitates behavior by enhancing perceptual sensitivity (sensory processing) and choice bias (decisional weighting) for attended information. Whether distinct neural substrates mediate these distinct components of attention remains unknown. We investigate the causal role of key nodes of the right posterior parietal cortex (rPPC) in the forebrain attention network in sensitivity versus bias control. Two groups of participants performed a cued attention task while we applied either inhibitory, repetitive transcranial magnetic stimulation (n = 28) or 40 Hz transcranial alternating current stimulation (n = 26) to the dorsal rPPC. We show that rPPC stimulation - with either modality - impairs task performance by selectively altering attentional modulation of bias but not sensitivity. Specifically, participants' bias toward the uncued, but not the cued, location reduced significantly following rPPC stimulation - an effect that was consistent across both neurostimulation cohorts. In sum, the dorsal rPPC causally mediates the reorienting of choice bias, one particular component of visual spatial attention.
Collapse
Affiliation(s)
- Ankita Sengupta
- Centre for Neuroscience, Indian Institute of Science, Bangalore, 560012, India
| | - Sanjna Banerjee
- Centre for Neuroscience, Indian Institute of Science, Bangalore, 560012, India
- Foundation of Art and Health India, Bangalore, 560066, India
| | - Suhas Ganesh
- Centre for Neuroscience, Indian Institute of Science, Bangalore, 560012, India
- Verily Life Sciences, San Francisco, CA, 94080, USA
| | - Shrey Grover
- Centre for Neuroscience, Indian Institute of Science, Bangalore, 560012, India
- Department of Psychological and Brain Sciences, Boston University, Boston, MA, 02215, USA
| | - Devarajan Sridharan
- Centre for Neuroscience, Indian Institute of Science, Bangalore, 560012, India.
- Department of Computer Science and Automation, Indian Institute of Science, Bangalore, 560012, India.
| |
Collapse
|
3
|
Manippa V, Nitsche MA, Filardi M, Vilella D, Scianatico G, Logroscino G, Rivolta D. Temporal gamma tACS and auditory stimulation affect verbal memory in healthy adults. Psychophysiology 2024:e14653. [PMID: 39014532 DOI: 10.1111/psyp.14653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 04/09/2024] [Accepted: 07/04/2024] [Indexed: 07/18/2024]
Abstract
Research suggests a potential of gamma oscillation entrainment for enhancing memory in Alzheimer's disease and healthy subjects. Gamma entrainment can be accomplished with oscillatory electrical, but also sensory stimulation. However, comparative studies between sensory stimulation and transcranial alternating current stimulation (tACS) effects on memory processes are lacking. This study examined the effects of rhythmic gamma auditory stimulation (rAS) and temporal gamma-tACS on verbal long-term memory (LTM) and working memory (WM) in 74 healthy individuals. Participants were assigned to two groups according to the stimulation techniques (rAS or tACS). Memory was assessed in three experimental blocks, in which each participant was administered with control, 40, and 60 Hz stimulation in counterbalanced order. All interventions were well-tolerated, and participants reported mostly comparable side effects between real stimulation (40 and 60 Hz) and the control condition. LTM immediate and delayed recall remained unaffected by stimulations, while immediate recall intrusions decreased during 60 Hz stimulation. Notably, 40 Hz interventions improved WM compared to control stimulations. These results highlight the potential of 60 and 40 Hz temporal cortex stimulation for reducing immediate LTM recall intrusions and improving WM performance, respectively, probably due to the entrainment of specific gamma oscillations in the auditory cortex. The results also shed light on the comparative effects of these neuromodulation tools on memory functions, and their potential applications for cognitive enhancement and in clinical trials.
Collapse
Affiliation(s)
- Valerio Manippa
- Department of Education, Psychology and Communication, University of Bari Aldo Moro, Bari, Italy
- Center for Neurodegenerative Diseases and the Aging Brain, University of Bari Aldo Moro at Pia Fondazione "Cardinale G. Panico", Lecce, Italy
- Department of Psychology and Neurosciences, Leibniz Research Centre for Working Environment and Human Factors, Dortmund, Germany
| | - Michael A Nitsche
- Department of Psychology and Neurosciences, Leibniz Research Centre for Working Environment and Human Factors, Dortmund, Germany
- German Center for Mental Health (DZPG), Bochum, Germany
- University Hospital OWL, Protestant Hospital of Bethel Foundation, University Clinic of Psychiatry and Psychotherapy, Bielefeld, Germany
| | - Marco Filardi
- Center for Neurodegenerative Diseases and the Aging Brain, University of Bari Aldo Moro at Pia Fondazione "Cardinale G. Panico", Lecce, Italy
- Department of Translational Biomedicine and Neurosciences (DiBraiN), University of Bari Aldo Moro, Bari, Italy
| | - Davide Vilella
- Center for Neurodegenerative Diseases and the Aging Brain, University of Bari Aldo Moro at Pia Fondazione "Cardinale G. Panico", Lecce, Italy
| | - Gaetano Scianatico
- Department of Education, Psychology and Communication, University of Bari Aldo Moro, Bari, Italy
| | - Giancarlo Logroscino
- Center for Neurodegenerative Diseases and the Aging Brain, University of Bari Aldo Moro at Pia Fondazione "Cardinale G. Panico", Lecce, Italy
- Department of Translational Biomedicine and Neurosciences (DiBraiN), University of Bari Aldo Moro, Bari, Italy
| | - Davide Rivolta
- Department of Education, Psychology and Communication, University of Bari Aldo Moro, Bari, Italy
| |
Collapse
|
4
|
Thiele C, Rufener KS, Repplinger S, Zaehle T, Ruhnau P. Transcranial temporal interference stimulation (tTIS) influences event-related alpha activity during mental rotation. Psychophysiology 2024:e14651. [PMID: 38997805 DOI: 10.1111/psyp.14651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 05/14/2024] [Accepted: 07/01/2024] [Indexed: 07/14/2024]
Abstract
Non-invasive brain stimulation techniques offer therapeutic potential for neurological and psychiatric disorders. However, current methods are often limited in their stimulation depth. The novel transcranial temporal interference stimulation (tTIS) aims to overcome this limitation by non-invasively targeting deeper brain regions. In this study, we aimed to evaluate the efficacy of tTIS in modulating alpha activity during a mental rotation task. The effects of tTIS were compared with transcranial alternating current stimulation (tACS) and a sham control. Participants were randomly assigned to a tTIS, tACS, or sham group. They performed alternating blocks of resting and mental rotation tasks before, during, and after stimulation. During the stimulation blocks, participants received 20 min of stimulation adjusted to their individual alpha frequency (IAF). We assessed shifts in resting state alpha power, event-related desynchronization (ERD) of alpha activity during mental rotation, as well as resulting improvements in behavioral performance. Our results indicate tTIS and tACS to be effective in modulating cortical alpha activity during mental rotation, leading to an increase in ERD from pre- to poststimulation as well as compared to sham stimulation. However, this increase in ERD was not correlated with enhanced mental rotation performance, and resting state alpha power remained unchanged. Our findings underscore the complex nature of tTIS and tACS efficacy, indicating that stimulation effects are more observable during active cognitive tasks, while their impacts are less pronounced on resting neuronal systems.
Collapse
Affiliation(s)
- Carsten Thiele
- Department of Neurology, Otto-von-Guericke-University, University Clinic of Magdeburg, Magdeburg, Germany
- Center for Behavioral Brain Sciences (CBBS), Otto-von-Guericke-Universität Magdeburg, Magdeburg, Germany
| | - Katharina S Rufener
- Center for Behavioral Brain Sciences (CBBS), Otto-von-Guericke-Universität Magdeburg, Magdeburg, Germany
- Department of Psychiatry, Psychotherapy and Psychosomatic Medicine of Childhood and Adolescents, Otto-von-Guericke-University, University Clinic of Magdeburg, Magdeburg, Germany
| | - Stefan Repplinger
- Department of Neurology, Otto-von-Guericke-University, University Clinic of Magdeburg, Magdeburg, Germany
- Center for Behavioral Brain Sciences (CBBS), Otto-von-Guericke-Universität Magdeburg, Magdeburg, Germany
| | - Tino Zaehle
- Department of Neurology, Otto-von-Guericke-University, University Clinic of Magdeburg, Magdeburg, Germany
- Center for Behavioral Brain Sciences (CBBS), Otto-von-Guericke-Universität Magdeburg, Magdeburg, Germany
| | - Philipp Ruhnau
- Center for Behavioral Brain Sciences (CBBS), Otto-von-Guericke-Universität Magdeburg, Magdeburg, Germany
- School of Psychology and Humanities, University of Central Lancashire, Preston, UK
| |
Collapse
|
5
|
Diedrich L, Kolhoff HI, Bergmann C, Bähr M, Antal A. Boosting working memory in the elderly: driving prefrontal theta-gamma coupling via repeated neuromodulation. GeroScience 2024:10.1007/s11357-024-01272-3. [PMID: 38992335 DOI: 10.1007/s11357-024-01272-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Accepted: 06/27/2024] [Indexed: 07/13/2024] Open
Abstract
The escalating global burden of age-related neurodegenerative diseases and associated healthcare costs necessitates innovative interventions to stabilize or enhance cognitive functions. Deficits in working memory (WM) are linked to alterations in prefrontal theta-gamma cross-frequency coupling. Low-intensity transcranial alternating current stimulation (tACS) has emerged as a non-invasive, low-cost approach capable of modulating ongoing oscillations in targeted brain areas through entrainment. This study investigates the impact of multi-session peak-coupled theta-gamma cross-frequency tACS administered to the dorsolateral prefrontal cortex (DLPFC) on WM performance in older adults. In a randomized, sham-controlled, triple-blinded design, 77 participants underwent 16 stimulation sessions over six weeks while performing n-back tasks. Signal detection measures revealed increased 2-back sensitivity and robust modulations of response bias, indicating improved WM and decision-making adaptations, respectively. No effects were observed in the 1-back condition, emphasizing dependencies on cognitive load. Repeated tACS reinforces behavioral changes, indicated by increasing effect sizes. This study supports prior research correlating prefrontal theta-gamma coupling with WM processes and provides unique insights into the neurocognitive benefits of repeated tACS intervention. The well-tolerated and highly effective multi-session tACS intervention among the elderly underscores its therapeutic potential in vulnerable populations.
Collapse
Affiliation(s)
- Lukas Diedrich
- Department of Neurology, University Medical Center Göttingen, Göttingen, Germany.
| | - Hannah I Kolhoff
- Department of Neurology, University Medical Center Göttingen, Göttingen, Germany
| | - Clara Bergmann
- Department of Neurology, University Medical Center Göttingen, Göttingen, Germany
| | - Mathias Bähr
- Department of Neurology, University Medical Center Göttingen, Göttingen, Germany
| | - Andrea Antal
- Department of Neurology, University Medical Center Göttingen, Göttingen, Germany
| |
Collapse
|
6
|
Sveva V, Cruciani A, Mancuso M, Santoro F, Latorre A, Monticone M, Rocchi L. Cerebellar Non-Invasive Brain Stimulation: A Frontier in Chronic Pain Therapy. J Pers Med 2024; 14:675. [PMID: 39063929 PMCID: PMC11277881 DOI: 10.3390/jpm14070675] [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: 05/08/2024] [Revised: 06/07/2024] [Accepted: 06/20/2024] [Indexed: 07/28/2024] Open
Abstract
Chronic pain poses a widespread and distressing challenge; it can be resistant to conventional therapies, often having significant side effects. Non-invasive brain stimulation (NIBS) techniques offer promising avenues for the safe and swift modulation of brain excitability. NIBS approaches for chronic pain management targeting the primary motor area have yielded variable outcomes. Recently, the cerebellum has emerged as a pivotal hub in human pain processing; however, the clinical application of cerebellar NIBS in chronic pain treatment remains limited. This review delineates the cerebellum's role in pain modulation, recent advancements in NIBS for cerebellar activity modulation, and novel biomarkers for assessing cerebellar function in humans. Despite notable progress in NIBS techniques and cerebellar activity assessment, studies targeting cerebellar NIBS for chronic pain treatment are limited in number. Nevertheless, positive outcomes in pain alleviation have been reported with cerebellar anodal transcranial direct current stimulation. Our review underscores the potential for further integration between cerebellar NIBS and non-invasive assessments of cerebellar function to advance chronic pain treatment strategies.
Collapse
Affiliation(s)
- Valerio Sveva
- Department of Anatomical and Histological Sciences, Legal Medicine and Orthopedics, University of Rome “Sapienza”, Piazzale Aldo Moro 5, 00185 Rome, Italy;
| | - Alessandro Cruciani
- Unit of Neurology, Neurophysiology, Neurobiology and Psychiatry, Department of Medicine and Surgery, Università Campus Bio-Medico di Roma, Via Alvaro del Portillo 21, 00128 Rome, Italy; (A.C.); (F.S.)
- Department of Medicine and Surgery, Fondazione Policlinico Universitario Campus Bio-Medico, Via Alvaro del Portillo 200, 00128 Rome, Italy
| | - Marco Mancuso
- Department of Human Neuroscience, University of Rome “Sapienza”, Viale dell’Università 30, 00185 Rome, Italy;
| | - Francesca Santoro
- Unit of Neurology, Neurophysiology, Neurobiology and Psychiatry, Department of Medicine and Surgery, Università Campus Bio-Medico di Roma, Via Alvaro del Portillo 21, 00128 Rome, Italy; (A.C.); (F.S.)
- Department of Medicine and Surgery, Fondazione Policlinico Universitario Campus Bio-Medico, Via Alvaro del Portillo 200, 00128 Rome, Italy
| | - Anna Latorre
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK;
| | - Marco Monticone
- Department of Surgical Sciences, University of Cagliari, 09124 Cagliari, Italy;
| | - Lorenzo Rocchi
- Department of Medical Sciences and Public Health, University of Cagliari, 09124 Cagliari, Italy
| |
Collapse
|
7
|
Boetzel C, Stecher HI, Herrmann CS. Aligning Event-Related Potentials with Transcranial Alternating Current Stimulation for Modulation-a Review. Brain Topogr 2024:10.1007/s10548-024-01055-1. [PMID: 38689065 DOI: 10.1007/s10548-024-01055-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Accepted: 04/18/2024] [Indexed: 05/02/2024]
Abstract
This review aims to demonstrate the connections between event-related potentials (ERPs), event-related oscillations (EROs), and non-invasive brain stimulation (NIBS), with a specific focus on transcranial alternating current stimulation (tACS). We begin with a short examination and discussion of the relation between ERPs and EROs. Then, we investigate the diverse fields of NIBS, highlighting tACS as a potent tool for modulating neural oscillations and influencing cognitive performance. Emphasizing the impact of tACS on individual ERP components, this article offers insights into the potential of conventional tACS for targeted stimulation of single ERP components. Furthermore, we review recent articles that explore a novel approach of tACS: ERP-aligned tACS. This innovative technique exploits the temporal precision of ERP components, aligning tACS with specific neural events to optimize stimulation effects and target the desired neural response. In conclusion, this review combines current knowledge to explore how ERPs, EROs, and NIBS interact, particularly highlighting the modulatory possibilities offered by tACS. The incorporation of ERP-aligned tACS introduces new opportunities for future research, advancing our understanding of the complex connection between neural oscillations and cognitive processes.
Collapse
Affiliation(s)
- Cindy Boetzel
- Experimental Psychology Lab, Department of Psychology, European Medical School, Cluster for Excellence "Hearing for All", Carl Von Ossietzky University, Ammerländer Heerstr. 114 - 118, 26129, Oldenburg, Germany
| | - Heiko I Stecher
- Experimental Psychology Lab, Department of Psychology, European Medical School, Cluster for Excellence "Hearing for All", Carl Von Ossietzky University, Ammerländer Heerstr. 114 - 118, 26129, Oldenburg, Germany
| | - Christoph S Herrmann
- Experimental Psychology Lab, Department of Psychology, European Medical School, Cluster for Excellence "Hearing for All", Carl Von Ossietzky University, Ammerländer Heerstr. 114 - 118, 26129, Oldenburg, Germany.
- Neuroimaging Unit, European Medical School, Carl Von Ossietzky University, Oldenburg, Germany.
- Research Center Neurosensory Science, Carl Von Ossietzky University, Oldenburg, Germany.
| |
Collapse
|
8
|
Mendes AJ, Lema A, Carvalho S, Leite J. Tailoring transcranial alternating current stimulation based on endogenous event-related P3 to modulate premature responses: a feasibility study. PeerJ 2024; 12:e17144. [PMID: 38584936 PMCID: PMC10998630 DOI: 10.7717/peerj.17144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 02/29/2024] [Indexed: 04/09/2024] Open
Abstract
Background Transcranial alternating current stimulation (tACS) is a brain stimulation method for modulating ongoing endogenous oscillatory activity at specified frequency during sensory and cognitive processes. Given the overlap between event-related potentials (ERPs) and event-related oscillations (EROs), ERPs can be studied as putative biomarkers of the effects of tACS in the brain during cognitive/sensory task performance. Objective This preliminary study aimed to test the feasibility of individually tailored tACS based on individual P3 (latency and frequency) elicited during a cued premature response task. Thus, tACS frequency was individually tailored to match target-P3 ERO for each participant. Likewise, the target onset in the task was adjusted to match the tACS phase and target-P3 latency. Methods Twelve healthy volunteers underwent tACS in two separate sessions while performing a premature response task. Target-P3 latency and ERO were calculated in a baseline block during the first session to allow a posterior synchronization between the tACS and the endogenous oscillatory activity. The cue and target-P3 amplitudes, delta/theta ERO, and power spectral density (PSD) were evaluated pre and post-tACS blocks. Results Target-P3 amplitude significantly increased after activetACS, when compared to sham. Evoked-delta during cue-P3 was decreased after tACS. No effects were found for delta ERO during target-P3 nor for the PSD and behavioral outcomes. Conclusion The present findings highlight the possible effect of phase synchronization between individualized tACS parameters and endogenous oscillatory activity, which may result in an enhancement of the underlying process (i.e., an increase of target-P3). However, an unsuccessful synchronization between tACS and EEG activity might also result in a decrease in the evoked-delta activity during cue-P3. Further studies are needed to optimize the parameters of endogenous activity and tACS synchronization. The implications of the current results for future studies, including clinical studies, are further discussed since transcranial alternating current stimulation can be individually tailored based on endogenous event-related P3 to modulate responses.
Collapse
Affiliation(s)
- Augusto J. Mendes
- Geneva Memory Center, Department of Rehabilitation and Geriatrics, University of Geneva, Geneva, Switzerland
- Laboratory of Neuroimaging of Aging (LANVIE), University of Geneva, Geneva, Switzerland
- Psychological Neuroscience Laboratory, CIPsi, School of Psychology, Universidade do Minho, Braga, Portugal
| | - Alberto Lema
- Psychological Neuroscience Laboratory, CIPsi, School of Psychology, Universidade do Minho, Braga, Portugal
| | - Sandra Carvalho
- Translational Neuropsychology Lab, Department of Education and Psychology, William James Center for Research (WJCR), University of Aveiro, Aveiro, Portugal
| | - Jorge Leite
- CINTESIS@RISE, CINTESIS.UPT, Universidade Portucalense Infante D. Henrique, Porto, Portugal
| |
Collapse
|
9
|
Zhao Z, Shirinpour S, Tran H, Wischnewski M, Opitz A. intensity- and frequency-specific effects of transcranial alternating current stimulation are explained by network dynamics. J Neural Eng 2024; 21:026024. [PMID: 38530297 DOI: 10.1088/1741-2552/ad37d9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 03/26/2024] [Indexed: 03/27/2024]
Abstract
Objective. Transcranial alternating current stimulation (tACS) can be used to non-invasively entrain neural activity and thereby cause changes in local neural oscillatory power. Despite its increased use in cognitive and clinical neuroscience, the fundamental mechanisms of tACS are still not fully understood.Approach. We developed a computational neuronal network model of two-compartment pyramidal neurons (PY) and inhibitory interneurons, which mimic the local cortical circuits. We modeled tACS with electric field strengths that are achievable in human applications. We then simulated intrinsic network activity and measured neural entrainment to investigate how tACS modulates ongoing endogenous oscillations.Main results. The intensity-specific effects of tACS are non-linear. At low intensities (<0.3 mV mm-1), tACS desynchronizes neural firing relative to the endogenous oscillations. At higher intensities (>0.3 mV mm-1), neurons are entrained to the exogenous electric field. We then further explore the stimulation parameter space and find that the entrainment of ongoing cortical oscillations also depends on stimulation frequency by following an Arnold tongue. Moreover, neuronal networks can amplify the tACS-induced entrainment via synaptic coupling and network effects. Our model shows that PY are directly entrained by the exogenous electric field and drive the inhibitory neurons.Significance. The results presented in this study provide a mechanistic framework for understanding the intensity- and frequency-specific effects of oscillating electric fields on neuronal networks. This is crucial for rational parameter selection for tACS in cognitive studies and clinical applications.
Collapse
Affiliation(s)
- Zhihe Zhao
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, United States of America
| | - Sina Shirinpour
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, United States of America
| | - Harry Tran
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, United States of America
| | - Miles Wischnewski
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, United States of America
| | - Alexander Opitz
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, United States of America
| |
Collapse
|
10
|
Wischnewski M, Berger TA, Opitz A, Alekseichuk I. Causal functional maps of brain rhythms in working memory. Proc Natl Acad Sci U S A 2024; 121:e2318528121. [PMID: 38536752 PMCID: PMC10998564 DOI: 10.1073/pnas.2318528121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 02/27/2024] [Indexed: 04/08/2024] Open
Abstract
Human working memory is a key cognitive process that engages multiple functional anatomical nodes across the brain. Despite a plethora of correlative neuroimaging evidence regarding the working memory architecture, our understanding of critical hubs causally controlling overall performance is incomplete. Causal interpretation requires cognitive testing following safe, temporal, and controllable neuromodulation of specific functional anatomical nodes. Such experiments became available in healthy humans with the advance of transcranial alternating current stimulation (tACS). Here, we synthesize findings of 28 placebo-controlled studies (in total, 1,057 participants) that applied frequency-specific noninvasive stimulation of neural oscillations and examined working memory performance in neurotypical adults. We use a computational meta-modeling method to simulate each intervention in realistic virtual brains and test reported behavioral outcomes against the stimulation-induced electric fields in different brain nodes. Our results show that stimulating anterior frontal and medial temporal theta oscillations and occipitoparietal gamma rhythms leads to significant dose-dependent improvement in working memory task performance. Conversely, prefrontal gamma modulation is detrimental to performance. Moreover, we found distinct spatial expression of theta subbands, where working memory changes followed orbitofrontal high-theta modulation and medial temporal low-theta modulation. Finally, all these results are driven by changes in working memory accuracy rather than processing time measures. These findings provide a fresh view of the working memory mechanisms, complementary to neuroimaging research, and propose hypothesis-driven targets for the clinical treatment of working memory deficits.
Collapse
Affiliation(s)
- Miles Wischnewski
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN55455
- Department of Experimental Psychology, University of Groningen, Groningen9712TS, The Netherlands
| | - Taylor A. Berger
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN55455
| | - Alexander Opitz
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN55455
| | - Ivan Alekseichuk
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN55455
| |
Collapse
|
11
|
Di Dona G, Zamfira DA, Battista M, Battaglini L, Perani D, Ronconi L. The role of parietal beta-band activity in the resolution of visual crowding. Neuroimage 2024; 289:120550. [PMID: 38382861 DOI: 10.1016/j.neuroimage.2024.120550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 02/16/2024] [Accepted: 02/19/2024] [Indexed: 02/23/2024] Open
Abstract
Visual crowding is the difficulty in identifying an object when surrounded by neighbouring flankers, representing a bottleneck for object perception. Crowding arises not only from the activity of visual areas but also from parietal areas and fronto-parietal network activity. Parietal areas would provide the dorsal-to-ventral guidance for object identification and the fronto-parietal network would modulate the attentional resolution. Several studies highlighted the relevance of beta oscillations (15-25 Hz) in these areas for visual crowding and other connatural visual phenomena. In the present study, we investigated the differential contribution of beta oscillations in the parietal cortex and fronto-parietal network in the resolution of visual crowding. During a crowding task with letter stimuli, high-definition transcranial Alternating Current Stimulation (tACS) in the beta band (18 Hz) was delivered bilaterally on parietal sites, on the right fronto-parietal network, and in a sham regime. Resting-state EEG was recorded before and after stimulation to measure tACS-induced aftereffects. The influence of crowding was reduced only when tACS was delivered bilaterally on parietal sites. In this condition, beta power was reduced after the stimulation. Furthermore, the magnitude of tACS-induced aftereffects varied as a function of individual differences in beta oscillations. Results corroborate the link between parietal beta oscillations and visual crowding, providing fundamental insights on brain rhythms underlying the dorsal-to-ventral guidance in visual perception and suggesting that beta tACS can induce plastic changes in these areas. Remarkably, these findings open new possibilities for neuromodulatory interventions for disorders characterised by abnormal crowding, such as dyslexia.
Collapse
Affiliation(s)
- Giuseppe Di Dona
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milano MI, Italy; School of Psychology, Vita-Salute San Raffaele University, Via Olgettina 58, 20132 Milano MI, Italy.
| | - Denisa Adina Zamfira
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milano MI, Italy; School of Psychology, Vita-Salute San Raffaele University, Via Olgettina 58, 20132 Milano MI, Italy
| | - Martina Battista
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milano MI, Italy; MoMiLab Research Unit, IMT School for Advanced Studies Lucca, Piazza S. Francesco 19, 55100 Lucca LU, Italy
| | - Luca Battaglini
- Dipartimento di Psicologia Generale, University of Padova, Via Venezia 8, 35131 Padova PD, Italy
| | - Daniela Perani
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milano MI, Italy; School of Psychology, Vita-Salute San Raffaele University, Via Olgettina 58, 20132 Milano MI, Italy
| | - Luca Ronconi
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milano MI, Italy; School of Psychology, Vita-Salute San Raffaele University, Via Olgettina 58, 20132 Milano MI, Italy.
| |
Collapse
|
12
|
Diedrich L, Kolhoff HI, Chakalov I, Vékony T, Németh D, Antal A. Prefrontal theta-gamma transcranial alternating current stimulation improves non-declarative visuomotor learning in older adults. Sci Rep 2024; 14:4955. [PMID: 38418511 PMCID: PMC10901881 DOI: 10.1038/s41598-024-55125-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Accepted: 02/20/2024] [Indexed: 03/01/2024] Open
Abstract
The rise in the global population of older adults underscores the significance to investigate age-related cognitive disorders and develop early treatment modalities. Previous research suggests that non-invasive transcranial Alternating Current Stimulation (tACS) can moderately improve cognitive decline in older adults. However, non-declarative cognition has received relatively less attention. This study investigates whether repeated (16-day) bilateral theta-gamma cross-frequency tACS targeting the Dorsolateral Prefrontal Cortex (DLPFC) enhances non-declarative memory. Computerized cognitive training was applied alongside stimulation to control for the state-of-the-brain. The Alternating Serial Reaction Time (ASRT) task was employed to assess non-declarative functions such as visuomotor skill and probabilistic sequence learning. Results from 35 participants aged 55-82 indicated that active tACS led to more substantial improvements in visuomotor skills immediately after treatment, which persisted 3 months later, compared to sham tACS. Treatment benefit was more pronounced in older adults of younger age and those with pre-existing cognitive decline. However, neither intervention group exhibited modulation of probabilistic sequence learning. These results suggest that repeated theta-gamma tACS can selectively improve distinct non-declarative cognitive aspects when targeting the DLPFC. Our findings highlight the therapeutic potential of tACS in addressing deficits in learning and retaining general skills, which could have a positive impact on the quality of life for cognitively impaired older individuals by preserving independence in daily activities.
Collapse
Affiliation(s)
- Lukas Diedrich
- Department of Neurology, University Medical Center Göttingen, Göttingen, Germany.
| | - Hannah I Kolhoff
- Department of Neurology, University Medical Center Göttingen, Göttingen, Germany
| | - Ivan Chakalov
- Department of Neurology, University Medical Center Göttingen, Göttingen, Germany
- Department of Anesthesiology, University Medical Center Göttingen, Göttingen, Germany
| | - Teodóra Vékony
- Centre de Recherche en Neurosciences de Lyon CRNL U1028 UMR5292, INSERM, CNRS, Université Claude Bernard Lyon 1, Bron, France
- Department of Education and Psychology, Faculty of Social Sciences, University of Atlántico Medio, Las Palmas de Gran Canaria, Spain
| | - Dezső Németh
- Centre de Recherche en Neurosciences de Lyon CRNL U1028 UMR5292, INSERM, CNRS, Université Claude Bernard Lyon 1, Bron, France
- BML-NAP Research Group, Institute of Psychology, Eötvös Loránd University and Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Budapest, Hungary
- Department of Education and Psychology, Faculty of Social Sciences, University of Atlántico Medio, Las Palmas de Gran Canaria, Spain
| | - Andrea Antal
- Department of Neurology, University Medical Center Göttingen, Göttingen, Germany
| |
Collapse
|
13
|
Ociepka M, Chinta SR, Basoń P, Chuderski A. No effects of the theta-frequency transcranial electrical stimulation for recall, attention control, and relation integration in working memory. Front Hum Neurosci 2024; 18:1354671. [PMID: 38439936 PMCID: PMC10910036 DOI: 10.3389/fnhum.2024.1354671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Accepted: 02/05/2024] [Indexed: 03/06/2024] Open
Abstract
Introduction Recent studies have suggested that transcranial alternating current stimulation (tACS), and especially the theta-frequency tACS, can improve human performance on working memory tasks. However, evidence to date is mixed. Moreover, the two WM tasks applied most frequently, namely the n-back and change-detection tasks, might not constitute canonical measures of WM capacity. Method In a relatively large sample of young healthy participants (N = 62), we administered a more canonical WM task that required stimuli recall, as well as we applied two WM tasks tapping into other key WM functions: attention control (the antisaccade task) and relational integration (the graph mapping task). The participants performed these three tasks three times: during the left frontal 5.5-Hz and the left parietal 5.5-Hz tACS session as well as during the sham session, with a random order of sessions. Attentional vigilance and subjective experience were monitored. Results For each task administered, we observed significant gains in accuracy neither for the frontal tACS session nor for the parietal tACS session, as compared to the sham session. By contrast, the scores on each task positively inter-correlated across the three sessions. Discussion The results suggest that canonical measures of WM capacity are strongly stable in time and hardly affected by theta-frequency tACS. Either the tACS effects observed in the n-back and change detection tasks do not generalize onto other WM tasks, or the tACS method has limited effectiveness with regard to WM, and might require further methodological advancements.
Collapse
Affiliation(s)
- Michał Ociepka
- Department of Cognitive Science, Institute of Philosophy, Jagiellonian University, Kraków, Poland
| | | | - Paweł Basoń
- Department of Cognitive Science, Institute of Philosophy, Jagiellonian University, Kraków, Poland
| | | |
Collapse
|
14
|
Pals M, Macke JH, Barak O. Trained recurrent neural networks develop phase-locked limit cycles in a working memory task. PLoS Comput Biol 2024; 20:e1011852. [PMID: 38315736 PMCID: PMC10868787 DOI: 10.1371/journal.pcbi.1011852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 02/15/2024] [Accepted: 01/22/2024] [Indexed: 02/07/2024] Open
Abstract
Neural oscillations are ubiquitously observed in many brain areas. One proposed functional role of these oscillations is that they serve as an internal clock, or 'frame of reference'. Information can be encoded by the timing of neural activity relative to the phase of such oscillations. In line with this hypothesis, there have been multiple empirical observations of such phase codes in the brain. Here we ask: What kind of neural dynamics support phase coding of information with neural oscillations? We tackled this question by analyzing recurrent neural networks (RNNs) that were trained on a working memory task. The networks were given access to an external reference oscillation and tasked to produce an oscillation, such that the phase difference between the reference and output oscillation maintains the identity of transient stimuli. We found that networks converged to stable oscillatory dynamics. Reverse engineering these networks revealed that each phase-coded memory corresponds to a separate limit cycle attractor. We characterized how the stability of the attractor dynamics depends on both reference oscillation amplitude and frequency, properties that can be experimentally observed. To understand the connectivity structures that underlie these dynamics, we showed that trained networks can be described as two phase-coupled oscillators. Using this insight, we condensed our trained networks to a reduced model consisting of two functional modules: One that generates an oscillation and one that implements a coupling function between the internal oscillation and external reference. In summary, by reverse engineering the dynamics and connectivity of trained RNNs, we propose a mechanism by which neural networks can harness reference oscillations for working memory. Specifically, we propose that a phase-coding network generates autonomous oscillations which it couples to an external reference oscillation in a multi-stable fashion.
Collapse
Affiliation(s)
- Matthijs Pals
- Machine Learning in Science, Excellence Cluster Machine Learning, University of Tübingen, Tübingen, Germany
- Tübingen AI Center, University of Tübingen, Tübingen, Germany
| | - Jakob H. Macke
- Machine Learning in Science, Excellence Cluster Machine Learning, University of Tübingen, Tübingen, Germany
- Tübingen AI Center, University of Tübingen, Tübingen, Germany
- Department Empirical Inference, Max Planck Institute for Intelligent Systems, Tübingen, Germany
| | - Omri Barak
- Rappaport Faculty of Medicine Technion, Israel Institute of Technology, Haifa, Israel
- Network Biology Research Laboratory, Israel Institute of Technology, Haifa, Israel
| |
Collapse
|
15
|
Lai MH, Yu XM, Lu Y, Wang HL, Fu W, Zhou HX, Li YL, Hu J, Xia J, Hu Z, Shan CL, Wang F, Wang C. Effectiveness and brain mechanism of multi-target transcranial alternating current stimulation (tACS) on motor learning in stroke patients: study protocol for a randomized controlled trial. Trials 2024; 25:97. [PMID: 38291500 PMCID: PMC10826150 DOI: 10.1186/s13063-024-07913-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 01/05/2024] [Indexed: 02/01/2024] Open
Abstract
BACKGROUND Transcranial alternating current stimulation (tACS) has proven to be an effective treatment for improving cognition, a crucial factor in motor learning. However, current studies are predominantly focused on the motor cortex, and the potential brain mechanisms responsible for the therapeutic effects are still unclear. Given the interconnected nature of motor learning within the brain network, we have proposed a novel approach known as multi-target tACS. This study aims to ascertain whether multi-target tACS is more effective than single-target stimulation in stroke patients and to further explore the potential underlying brain mechanisms by using techniques such as transcranial magnetic stimulation (TMS) and magnetic resonance imaging (MRI). METHODS This study employs a double-blind, sham-controlled, randomized controlled trial design with a 2-week intervention period. Both participants and outcome assessors will remain unaware of treatment allocation throughout the study. Thirty-nine stroke patients will be recruited and randomized into three distinct groups, including the sham tACS group (SS group), the single-target tACS group (ST group), and the multi-target tACS group (MT group), at a 1:1:1 ratio. The primary outcomes are series reaction time tests (SRTTs) combined with electroencephalograms (EEGs). The secondary outcomes include motor evoked potential (MEP), central motor conduction time (CMCT), short interval intracortical inhibition (SICI), intracortical facilitation (ICF), magnetic resonance imaging (MRI), Box and Block Test (BBT), and blood sample RNA sequencing. The tACS interventions for all three groups will be administered over a 2-week period, with outcome assessments conducted at baseline (T0) and 1 day (T1), 7 days (T2), and 14 days (T3) of the intervention phase. DISCUSSION The study's findings will determine the potential of 40-Hz tACS to improve motor learning in stroke patients. Additionally, it will compare the effectiveness of multi-target and single-target approaches, shedding light on their respective improvement effects. Through the utilization of techniques such as TMS and MRI, the study aims to uncover the underlying brain mechanisms responsible for the therapeutic impact. Furthermore, the intervention has the potential to facilitate motor learning efficiency, thereby contributing to the advancement of future stroke rehabilitation treatment. TRIAL REGISTRATION Chinese Clinical Trial Registry ChiCTR2300073465. Registered on 11 July 2023.
Collapse
Affiliation(s)
- Ming-Hui Lai
- Department of Rehabilitation, Seventh People's Hospital of Shanghai University of Traditional Chinese Medicine, Datong Rd. 358, Shanghai, 200137, China
| | - Xiao-Ming Yu
- Department of Rehabilitation, Seventh People's Hospital of Shanghai University of Traditional Chinese Medicine, Datong Rd. 358, Shanghai, 200137, China
| | - Yan Lu
- Department of Rehabilitation, Seventh People's Hospital of Shanghai University of Traditional Chinese Medicine, Datong Rd. 358, Shanghai, 200137, China
| | - Hong-Lin Wang
- Department of Rehabilitation, Seventh People's Hospital of Shanghai University of Traditional Chinese Medicine, Datong Rd. 358, Shanghai, 200137, China
| | - Wang Fu
- Department of Neurology, Seventh People's Hospital of Shanghai University of Traditional Chinese Medicine, Shanghai, 200137, China
| | - Huan-Xia Zhou
- Department of Rehabilitation, Seventh People's Hospital of Shanghai University of Traditional Chinese Medicine, Datong Rd. 358, Shanghai, 200137, China
| | - Yuan-Li Li
- Department of Rehabilitation, Seventh People's Hospital of Shanghai University of Traditional Chinese Medicine, Datong Rd. 358, Shanghai, 200137, China
- Engineering Research Center of Traditional Chinese Medicine Intelligent Rehabilitation, Ministry of Education, Shanghai, 201203, China
- School of Rehabilitation Science, Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, China
| | - Jun Hu
- The Second Rehabilitation Hospital of Shanghai, Shanghai, 200435, China
| | - Jiayi Xia
- The Second Rehabilitation Hospital of Shanghai, Shanghai, 200435, China
| | - Zekai Hu
- The Second Rehabilitation Hospital of Shanghai, Shanghai, 200435, China
| | - Chun-Lei Shan
- Department of Rehabilitation, Seventh People's Hospital of Shanghai University of Traditional Chinese Medicine, Datong Rd. 358, Shanghai, 200137, China
- Engineering Research Center of Traditional Chinese Medicine Intelligent Rehabilitation, Ministry of Education, Shanghai, 201203, China
- School of Rehabilitation Science, Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, China
| | - Feng Wang
- Department of Neurology, Seventh People's Hospital of Shanghai University of Traditional Chinese Medicine, Shanghai, 200137, China
| | - Cong Wang
- Department of Rehabilitation, Seventh People's Hospital of Shanghai University of Traditional Chinese Medicine, Datong Rd. 358, Shanghai, 200137, China.
- Engineering Research Center of Traditional Chinese Medicine Intelligent Rehabilitation, Ministry of Education, Shanghai, 201203, China.
- School of Rehabilitation Science, Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, China.
- The Second Rehabilitation Hospital of Shanghai, Shanghai, 200435, China.
- Queensland Brain Institute, the University of Queensland, Brisbane, 4072, Australia.
| |
Collapse
|
16
|
Mattioli F, Maglianella V, D'Antonio S, Trimarco E, Caligiore D. Non-invasive brain stimulation for patients and healthy subjects: Current challenges and future perspectives. J Neurol Sci 2024; 456:122825. [PMID: 38103417 DOI: 10.1016/j.jns.2023.122825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 11/22/2023] [Accepted: 11/28/2023] [Indexed: 12/19/2023]
Abstract
Non-invasive brain stimulation (NIBS) techniques have a rich historical background, yet their utilization has witnessed significant growth only recently. These techniques encompass transcranial electrical stimulation and transcranial magnetic stimulation, which were initially employed in neuroscience to explore the intricate relationship between the brain and behaviour. However, they are increasingly finding application in research contexts as a means to address various neurological, psychiatric, and neurodegenerative disorders. This article aims to fulfill two primary objectives. Firstly, it seeks to showcase the current state of the art in the clinical application of NIBS, highlighting how it can improve and complement existing treatments. Secondly, it provides a comprehensive overview of the utilization of NIBS in augmenting the brain function of healthy individuals, thereby enhancing their performance. Furthermore, the article delves into the points of convergence and divergence between these two techniques. It also addresses the existing challenges and future prospects associated with NIBS from ethical and research standpoints.
Collapse
Affiliation(s)
- Francesco Mattioli
- AI2Life s.r.l., Innovative Start-Up, ISTC-CNR Spin-Off, Via Sebino 32, 00199 Rome, Italy; School of Computing, Electronics and Mathematics, University of Plymouth, Drake Circus, Plymouth PL4 8AA, United Kingdom
| | - Valerio Maglianella
- Computational and Translational Neuroscience Laboratory, Institute of Cognitive Sciences and Technologies, National Research Council (CTNLab-ISTC-CNR), Via San Martino della Battaglia 44, 00185 Rome, Italy
| | - Sara D'Antonio
- Computational and Translational Neuroscience Laboratory, Institute of Cognitive Sciences and Technologies, National Research Council (CTNLab-ISTC-CNR), Via San Martino della Battaglia 44, 00185 Rome, Italy
| | - Emiliano Trimarco
- Computational and Translational Neuroscience Laboratory, Institute of Cognitive Sciences and Technologies, National Research Council (CTNLab-ISTC-CNR), Via San Martino della Battaglia 44, 00185 Rome, Italy
| | - Daniele Caligiore
- AI2Life s.r.l., Innovative Start-Up, ISTC-CNR Spin-Off, Via Sebino 32, 00199 Rome, Italy; Computational and Translational Neuroscience Laboratory, Institute of Cognitive Sciences and Technologies, National Research Council (CTNLab-ISTC-CNR), Via San Martino della Battaglia 44, 00185 Rome, Italy.
| |
Collapse
|
17
|
Lim RY, Ang KK, Chew E, Guan C. A Review on Motor Imagery with Transcranial Alternating Current Stimulation: Bridging Motor and Cognitive Welfare for Patient Rehabilitation. Brain Sci 2023; 13:1584. [PMID: 38002544 PMCID: PMC10670393 DOI: 10.3390/brainsci13111584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 10/26/2023] [Accepted: 11/10/2023] [Indexed: 11/26/2023] Open
Abstract
Research has shown the effectiveness of motor imagery in patient motor rehabilitation. Transcranial electrical stimulation has also demonstrated to improve patient motor and non-motor performance. However, mixed findings from motor imagery studies that involved transcranial electrical stimulation suggest that current experimental protocols can be further improved towards a unified design for consistent and effective results. This paper aims to review, with some clinical and neuroscientific findings from literature as support, studies of motor imagery coupled with different types of transcranial electrical stimulation and their experiments onhealthy and patient subjects. This review also includes the cognitive domains of working memory, attention, and fatigue, which are important for designing consistent and effective therapy protocols. Finally, we propose a theoretical all-inclusive framework that synergizes the three cognitive domains with motor imagery and transcranial electrical stimulation for patient rehabilitation, which holds promise of benefiting patients suffering from neuromuscular and cognitive disorders.
Collapse
Affiliation(s)
- Rosary Yuting Lim
- Institute for Infocomm Research, Agency for Science Technology and Research, A*STAR, 1 Fusionopolis Way, #21-01 Connexis, Singapore 138632, Singapore;
| | - Kai Keng Ang
- Institute for Infocomm Research, Agency for Science Technology and Research, A*STAR, 1 Fusionopolis Way, #21-01 Connexis, Singapore 138632, Singapore;
- School of Computer Science and Engineering, Nanyang Technological University, 50 Nanyang Ave., #32 Block N4 #02a, Singapore 639798, Singapore;
| | - Effie Chew
- Division of Rehabilitation Medicine, Department of Medicine, National University Hospital, 5 Lower Kent Ridge Rd, Singapore 119074, Singapore;
- Yong Loo Lin School of Medicine, National University of Singapore, 10 Medical Dr, Singapore 117597, Singapore
| | - Cuntai Guan
- School of Computer Science and Engineering, Nanyang Technological University, 50 Nanyang Ave., #32 Block N4 #02a, Singapore 639798, Singapore;
| |
Collapse
|
18
|
Chen X, Wu Y, Shi X, Zhou Z, Feng T, Ren M, Li Y, Shan C. Neuromodulatory effects of high-definition theta transcranial alternating current stimulation on the parietal cortex: a pilot study of healthy males. Front Neurosci 2023; 17:1255124. [PMID: 38027510 PMCID: PMC10665503 DOI: 10.3389/fnins.2023.1255124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2023] [Accepted: 10/23/2023] [Indexed: 12/01/2023] Open
Abstract
Introduction Transcranial alternating current stimulation (tACS) can regulate brain functions by modulating endogenous brain rhythms. Theta-band neural oscillations are associated with memory function. In particular, theta neural oscillatory power evoked in the parietal cortex is closely related to memory retrieval processes. In this study, the immediate effects of high-definition theta transcranial alternating current stimulation (HDθ-tACS) on the human left parietal cortex were investigated using short-latency afferent inhibition (SAI) and electroencephalography (EEG). Methods Ten subjects participated in this study. We used 6-Hz HD tACS to stimulate the left parietal cortex for 15 min. SAI was calculated, and non-linear dynamic analysis of the EEG was performed to analyze neuronal function after HD θ-tACS. Results The results showed a significant decrease in SAI (p < 0.05), while the left frontoparietal network was reinforced, leading to brain lateralization after HD θ-tACS. During performance of a memory task, F3 signals showed a significant upward trend in approximate entropy following treatment (p < 0.05). There was also a significant decrease in cross-approximate entropy in the C3-C4 and P3-P4 connections following the intervention (p < 0.05) in a resting eyes-open condition and in the memory task condition. Discussion In conclusion, HD θ-tACS could alter cholinergic transmission and cortical excitability between the parietal and motor cortices, as well as reinforcing the frontoparietal network and the left-lateralization phenomenon, which may facilitate memory formation, encoding, and consolidation.
Collapse
Affiliation(s)
- Xixi Chen
- School of Rehabilitation Science, Shanghai University of Traditional Chinese Medicine, Shanghai, China
- Institute of Rehabilitation, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yuwei Wu
- Department of Rehabilitation Medicine, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Xiaolong Shi
- School of Rehabilitation Science, Shanghai University of Traditional Chinese Medicine, Shanghai, China
- Institute of Rehabilitation, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Zhiqing Zhou
- School of Rehabilitation Science, Shanghai University of Traditional Chinese Medicine, Shanghai, China
- Institute of Rehabilitation, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Tingyi Feng
- Department of Rehabilitation Medicine, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Meng Ren
- School of Rehabilitation Science, Shanghai University of Traditional Chinese Medicine, Shanghai, China
- Institute of Rehabilitation, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yuanli Li
- Engineering Research Center of Traditional Chinese Medicine Intelligent Rehabilitation, Ministry of Education, Shanghai, China
- Department of Rehabilitation, Shanghai Seventh People’s Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Chunlei Shan
- School of Rehabilitation Science, Shanghai University of Traditional Chinese Medicine, Shanghai, China
- Institute of Rehabilitation, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Department of Rehabilitation Medicine, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China
- Engineering Research Center of Traditional Chinese Medicine Intelligent Rehabilitation, Ministry of Education, Shanghai, China
- Department of Rehabilitation Medicine, Tong Ren Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| |
Collapse
|
19
|
Xiao Y, Zhou J, Zhou R, Liu Y, Lü J, Huang L. Fronto-parietal theta high-definition transcranial alternating current stimulation may modulate working memory under postural control conditions in young healthy adults. Front Hum Neurosci 2023; 17:1265600. [PMID: 38021229 PMCID: PMC10666918 DOI: 10.3389/fnhum.2023.1265600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Accepted: 10/16/2023] [Indexed: 12/01/2023] Open
Abstract
Objects This study aimed to investigate the immediate effects of fronto-parietal θ HD-tACS on a dual task of working memory-postural control. Methods In this within-subject cross-over pilot study, we assessed the effects of 20 min of 6 Hz-tACS targeting both the left dorsolateral prefrontal cortex (lDLPFC) and posterior parietal cortex (PPC) in 20 healthy adults (age: 21.6 ± 1.3 years). During each session, single- and dual-task behavioral tests (working memory single-task, static tandem standing, and a dual-task of working memory-postural control) and closed-eye resting-state EEG were assessed before and immediately after stimulation. Results Within the tACS group, we found a 5.3% significant decrease in working memory response time under the dual-task following tACS (t = -3.157, p = 0.005, Cohen's d = 0.742); phase synchronization analysis revealed a significant increase in the phase locking value (PLV) of θ band between F3 and P3 after tACS (p = 0.010, Cohen's d = 0.637). Correlation analyses revealed a significant correlation between increased rs-EEG θ power in the F3 and P3 channels and faster reaction time (r = -0.515, p = 0.02; r = -0.483, p = 0.031, respectively) in the dual-task working memory task after tACS. However, no differences were observed on either upright postural control performance or rs-EEG results (p-values <0.05). Conclusion Fronto-parietal θ HD-tACS has the potential of being a neuromodulatory tool for improving working memory performance in dual-task situations, but its effect on the modulation of concurrently performed postural control tasks requires further investigation.
Collapse
Affiliation(s)
- Yanwen Xiao
- Key Laboratory of Exercise and Health Sciences of Ministry of Education, Shanghai University of Sport, Shanghai, China
- Department of Rehabilitation Medicine, Shenshan Medical Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Shanwei, Guangdong, China
| | - Junhong Zhou
- Hinda and Arthur Marcus Institute for Aging Research, Harvard Medical School, Boston, MA, United States
| | - Rong Zhou
- Key Laboratory of Exercise and Health Sciences of Ministry of Education, Shanghai University of Sport, Shanghai, China
| | - Yu Liu
- Key Laboratory of Exercise and Health Sciences of Ministry of Education, Shanghai University of Sport, Shanghai, China
| | - Jiaojiao Lü
- Key Laboratory of Exercise and Health Sciences of Ministry of Education, Shanghai University of Sport, Shanghai, China
| | - Lingyan Huang
- Key Laboratory of Exercise and Health Sciences of Ministry of Education, Shanghai University of Sport, Shanghai, China
| |
Collapse
|
20
|
Chang WS, Liang WK, Li DH, Muggleton NG, Balachandran P, Huang NE, Juan CH. The association between working memory precision and the nonlinear dynamics of frontal and parieto-occipital EEG activity. Sci Rep 2023; 13:14252. [PMID: 37653059 PMCID: PMC10471634 DOI: 10.1038/s41598-023-41358-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 08/24/2023] [Indexed: 09/02/2023] Open
Abstract
Electrophysiological working memory (WM) research shows brain areas communicate via macroscopic oscillations across frequency bands, generating nonlinear amplitude modulation (AM) in the signal. Traditionally, AM is expressed as the coupling strength between the signal and a prespecified modulator at a lower frequency. Therefore, the idea of AM and coupling cannot be studied separately. In this study, 33 participants completed a color recall task while their brain activity was recorded through EEG. The AM of the EEG data was extracted using the Holo-Hilbert spectral analysis (HHSA), an adaptive method based on the Hilbert-Huang transforms. The results showed that WM load modulated parieto-occipital alpha/beta power suppression. Furthermore, individuals with higher frontal theta power and lower parieto-occipital alpha/beta power exhibited superior WM precision. In addition, the AM of parieto-occipital alpha/beta power predicted WM precision after presenting a target-defining probe array. The phase-amplitude coupling (PAC) between the frontal theta phase and parieto-occipital alpha/beta AM increased with WM load while processing incoming stimuli, but the PAC itself did not predict the subsequent recall performance. These results suggest frontal and parieto-occipital regions communicate through theta-alpha/beta PAC. However, the overall recall precision depends on the alpha/beta AM following the onset of the retro cue.
Collapse
Affiliation(s)
- Wen-Sheng Chang
- Institute of Cognitive Neuroscience, College of Health Sciences and Technology, National Central University, Taoyuan City, Taiwan
| | - Wei-Kuang Liang
- Institute of Cognitive Neuroscience, College of Health Sciences and Technology, National Central University, Taoyuan City, Taiwan
- Cognitive Intelligence and Precision Healthcare Center, National Central University, Taoyuan City, Taiwan
| | - Dong-Han Li
- Institute of Cognitive Neuroscience, College of Health Sciences and Technology, National Central University, Taoyuan City, Taiwan
- Cognitive Intelligence and Precision Healthcare Center, National Central University, Taoyuan City, Taiwan
| | - Neil G Muggleton
- Institute of Cognitive Neuroscience, College of Health Sciences and Technology, National Central University, Taoyuan City, Taiwan
- Cognitive Intelligence and Precision Healthcare Center, National Central University, Taoyuan City, Taiwan
- Institute of Cognitive Neuroscience, University College London, London, UK
- Department of Psychology, Goldsmiths, University of London, London, UK
| | - Prasad Balachandran
- Institute of Cognitive Neuroscience, College of Health Sciences and Technology, National Central University, Taoyuan City, Taiwan
- Taiwan International Graduate Program in Interdisciplinary Neuroscience, National Cheng Kung University and Academia Sinica, Taipei, Taiwan
| | - Norden E Huang
- Cognitive Intelligence and Precision Healthcare Center, National Central University, Taoyuan City, Taiwan
- Data Analysis and Application Laboratory, The First Institute of Oceanography, Qingdao, China
| | - Chi-Hung Juan
- Institute of Cognitive Neuroscience, College of Health Sciences and Technology, National Central University, Taoyuan City, Taiwan.
- Cognitive Intelligence and Precision Healthcare Center, National Central University, Taoyuan City, Taiwan.
- Department of Psychology, Kaohsiung Medical University, Kaohsiung, Taiwan.
| |
Collapse
|
21
|
Rauh J, Müller ASM, Nolte G, Haaf M, Mußmann M, Steinmann S, Mulert C, Leicht G. Comparison of transcranial brain stimulation approaches: prefrontal theta alternating current stimulation enhances working memory performance. Front Psychiatry 2023; 14:1140361. [PMID: 37457770 PMCID: PMC10348840 DOI: 10.3389/fpsyt.2023.1140361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Accepted: 06/05/2023] [Indexed: 07/18/2023] Open
Abstract
Introduction One of the most important cognitive functions in our everyday life is the working memory (WM). In several neuropsychiatric diseases such as ADHD or schizophrenia WM deficits can be observed, making it an attractive target for non-invasive brain stimulation methods like transcranial electrical stimulation (tES). However, the literature shows rather heterogeneous results of tES effects on WM performance. fMRI meta-analyses have identified a WM network including frontoparietal brain areas such as the dorsolateral prefrontal cortex (DLPFC) and the posterior parietal cortex (PPC). Neurophysiological studies revealed oscillatory activity in the theta band frequency range to be of crucial functional relevance for WM processes. Based on this, transcranial alternating current stimulation (tACS) in the theta frequency range targeting DLPFC and PPC in a spatially optimized way might further improve effects of tES on WM performance. Methods Sixteen healthy subjects were stimulated with varying stimulation settings on four different days in a counterbalanced within-subject design. These setups included the application of (1) tACS with a frequency of 5 Hz (theta frequency range) over the left DLPFC and (2) the right superior parietal cortex, (3) transcranial direct current stimulation (tDCS) of the DLPFC and (4) a sham stimulation condition during the online performance of a visual delayed-match-to-sample task with varying working memory load. We introduce a procedure to calculate an optimal tES model revealing optimized high-density setups for the present study for 3 cathodes and 1 anode and stimulation currents of 1.5 mA. Results A significant interaction effect of stimulation type and load condition on working memory capacity was found. This was reflected by a significant improvement of WM performance in the high load condition during tACS over the left DLPFC compared with sham stimulation, which was not the case for our parietal tACS or tDCS setup. Discussion Working memory performance can be improved with optimized high-definition tACS with a frequency of 5 Hz over the left DLPFC. The conception of different mechanisms underlying transcranial electrical stimulation with alternating and direct currents is supported by these results. Patients suffering from working memory impairments due to neuropsychiatric diseases might potentially benefit from this brain stimulation approach.
Collapse
Affiliation(s)
- Jonas Rauh
- Psychiatry Neuroimaging Branch, Department of Psychiatry and Psychotherapy, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Anne S. M. Müller
- Psychiatry Neuroimaging Branch, Department of Psychiatry and Psychotherapy, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Guido Nolte
- Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Moritz Haaf
- Psychiatry Neuroimaging Branch, Department of Psychiatry and Psychotherapy, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Marius Mußmann
- Psychiatry Neuroimaging Branch, Department of Psychiatry and Psychotherapy, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Saskia Steinmann
- Psychiatry Neuroimaging Branch, Department of Psychiatry and Psychotherapy, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Christoph Mulert
- Psychiatry Neuroimaging Branch, Department of Psychiatry and Psychotherapy, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Center of Psychiatry, Justus-Liebig University, Giessen, Germany
| | - Gregor Leicht
- Psychiatry Neuroimaging Branch, Department of Psychiatry and Psychotherapy, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| |
Collapse
|
22
|
Nissim NR, McAfee DC, Edwards S, Prato A, Lin JX, Lu Z, Coslett HB, Hamilton RH. Efficacy of Transcranial Alternating Current Stimulation in the Enhancement of Working Memory Performance in Healthy Adults: A Systematic Meta-Analysis. Neuromodulation 2023; 26:728-737. [PMID: 36759231 PMCID: PMC10257732 DOI: 10.1016/j.neurom.2022.12.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 12/22/2022] [Accepted: 12/29/2022] [Indexed: 02/10/2023]
Abstract
BACKGROUND Transcranial alternating current stimulation (tACS)-a noninvasive brain stimulation technique that modulates cortical oscillations in the brain-has shown the capacity to enhance working memory (WM) abilities in healthy individuals. The efficacy of tACS in the improvement of WM performance in healthy individuals is not yet fully understood. OBJECTIVE/HYPOTHESIS This meta-analysis aimed to systematically evaluate the efficacy of tACS in the enhancement of WM in healthy individuals and to assess moderators of response to stimulation. We hypothesized that active tACS would significantly enhance WM compared with sham. We further hypothesized that it would do so in a task-dependent manner and that differing stimulation parameters would affect response to tACS. MATERIALS AND METHODS Ten tACS studies met the inclusion criteria and provided 32 effects in the overall analysis. Random-effect models assessed mean change scores on WM tasks from baseline to poststimulation. The included studies involved varied in stimulation parameters, between-subject and within-subject study designs, and online vs offline tACS. RESULTS We observed a significant, heterogeneous, and moderate effect size for active tACS in the enhancement of WM performance over sham (Cohen's d = 0.5). Cognitive load, task domain, session number, and stimulation region showed a significant relationship between active tACS and enhanced WM behavior over sham. CONCLUSIONS Our findings indicate that active tACS enhances WM performance in healthy individuals compared with sham. Future randomized controlled trials are needed to further explore key parameters, including personalized stimulation vs standardized electroencephalography frequencies and maintenance of tACS effects, and whether tACS-induced effects translate to populations with WM impairments.
Collapse
Affiliation(s)
- Nicole R Nissim
- Laboratory for Cognition and Neural Stimulation, Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA; Moss Rehabilitation Research Institute, Einstein Medical Center, Elkins Park, PA, USA.
| | - Darrian C McAfee
- Laboratory for Cognition and Neural Stimulation, Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Shanna Edwards
- Laboratory for Cognition and Neural Stimulation, Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Amara Prato
- Laboratory for Cognition and Neural Stimulation, Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Jennifer X Lin
- Laboratory for Cognition and Neural Stimulation, Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Zhiye Lu
- Laboratory for Cognition and Neural Stimulation, Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - H Branch Coslett
- Laboratory for Cognition and Neural Stimulation, Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA; Moss Rehabilitation Research Institute, Einstein Medical Center, Elkins Park, PA, USA
| | - Roy H Hamilton
- Laboratory for Cognition and Neural Stimulation, Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA; Moss Rehabilitation Research Institute, Einstein Medical Center, Elkins Park, PA, USA
| |
Collapse
|
23
|
Wang Y, Zhang Y, Hou P, Dong G, Shi L, Li W, Wei R, Li X. Excitability changes induced in the human auditory cortex by transcranial alternating current stimulation. Neurosci Lett 2023; 792:136960. [PMID: 36372094 DOI: 10.1016/j.neulet.2022.136960] [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: 12/31/2021] [Revised: 10/18/2022] [Accepted: 11/07/2022] [Indexed: 11/11/2022]
Abstract
Transcranial alternating current stimulation (tACS) has been widely studied for its ability to regulate motor, perceptual, and cognitive functions. Given the unique frequency specificity of tACS, it is expected to directly target rhythmic activity in the typical electroencephalogram (EEG) range. After tACS stimulation, changes in stimulation-induced and evoked activities can be inspected. Detecting changes in auditory evoked activity after different frequencies of tACS stimulation will be helpful for further revealing the influence of tACS on the excitation/inhibition of γ activity in the auditory cortex. Using a randomized repeated measures design, this study assessed the effects of alpha(α)-tACS and gamma(γ)-tACS on the auditory steady-state response (ASSR) in 11 normal-hearing participants. Participants attended four sessions held at least one week apart, receiving tACS or sham treatment. The results indicated that α-tACS had an inhibitory effect on 40-Hz ASSR compared to both γ-tACS and sham tACS, which occurred 30 min after stimulation. Taken together, these findings contribute to the understanding of tACS-induced excitability changes in the human auditory cortex, helping reveal the neurophysiological changes after tACS.
Collapse
Affiliation(s)
- Yao Wang
- Department of Biomedical Engineering, School of Life Sciences, Tiangong University, Tianjin 300387, China; School of Precision Instruments and Optoelectronics Engineering Tianjin University, Tianjin University, Tianjin 300072, China
| | - Yue Zhang
- Department of Biomedical Engineering, School of Life Sciences, Tiangong University, Tianjin 300387, China
| | - Peiyun Hou
- Department of Biomedical Engineering, School of Life Sciences, Tiangong University, Tianjin 300387, China
| | - Gaoyuan Dong
- School of Electrical and Electronic Engineering, Tiangong University, Tianjin 300387, China
| | - Limeng Shi
- Department of Biomedical Engineering, School of Life Sciences, Tiangong University, Tianjin 300387, China
| | - Weiming Li
- Department of Biomedical Engineering, School of Life Sciences, Tiangong University, Tianjin 300387, China
| | - Ran Wei
- Department of Biomedical Engineering, School of Life Sciences, Tiangong University, Tianjin 300387, China
| | - Xiaojie Li
- Department of Biomedical Engineering, School of Life Sciences, Tiangong University, Tianjin 300387, China.
| |
Collapse
|
24
|
10 Minutes Frontal 40 Hz tACS-Effects on Working Memory Tested by Luck-Vogel Task. Behav Sci (Basel) 2022; 13:bs13010039. [PMID: 36661611 PMCID: PMC9855106 DOI: 10.3390/bs13010039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Revised: 12/21/2022] [Accepted: 12/27/2022] [Indexed: 01/03/2023] Open
Abstract
Working memory is a cognitive process that involves short-term active maintenance, flexible updating, and processing of goal- or task-relevant information. All frequency bands are involved in working memory. The activities of the theta and gamma frequency bands in the frontoparietal network are highly involved in working memory processes; theta oscillations play a role in the temporal organization of working memory items, and gamma oscillations influence the maintenance of information in working memory. Transcranial alternating current stimulation (tACS) results in frequency-specific modulation of endogenous oscillations and has shown promising results in cognitive neuroscience. The electrophysiological and behavioral changes induced by the modulation of endogenous gamma frequency in the prefrontal cortex using tACS have not been extensively studied in the context of working memory. Therefore, we aimed to investigate the effects of frontal gamma-tACS on working memory outcomes. We hypothesized that a 10-min gamma tACS administered over the frontal cortex would significantly improve working memory outcomes. Young healthy participants performed Luck-Vogel cognitive behavioral tasks with simultaneous pre- and post-intervention EEG recording (Sham versus 40 Hz tACS). Data from forty-one participants: sham (15 participants) and tACS (26 participants), were used for the statistical and behavioral analysis. The relative changes in behavioral outcomes and EEG due to the intervention were analyzed. The results show that tACS caused an increase in the power spectral density in the high beta and low gamma EEG bands and a decrease in left-right coherence. On the other hand, tACS had no significant effect on success rates and response times. Conclusion: 10 min of frontal 40 Hz tACS was not sufficient to produce detectable behavioral effects on working memory, whereas electrophysiological changes were evident. The limitations of the current stimulation protocol and future directions are discussed in detail in the following sections.
Collapse
|
25
|
Lee ARYB, Yau CE, Mai AS, Tan WA, Ong BSY, Yam NE, Ho CSH. Transcranial alternating current stimulation and its effects on cognition and the treatment of psychiatric disorders: a systematic review and meta-analysis. Ther Adv Chronic Dis 2022; 13:20406223221140390. [PMID: 36479141 PMCID: PMC9720798 DOI: 10.1177/20406223221140390] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 11/03/2022] [Indexed: 03/25/2024] Open
Abstract
BACKGROUND Transcranial alternating current stimulation (TACS) is a non-invasive method of brain stimulation that is hypothesised to alter cortical excitability and brain electrical activity, modulating functional connectivity within the brain. Several trials have demonstrated its potential in treating psychiatric disorders such as depression and schizophrenia. OBJECTIVES To study the efficacy of TACS in ameliorating symptoms of depression and schizophrenia in patients and its effects on cognition in patients and healthy subjects compared to sham stimulation. DESIGN Systematic review with meta-analysis. DATA SOURCES AND METHODS This PROSPERO-registered systematic review (CRD42022331149) is reported according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. PubMed, EMBASE, CENTRAL and PsycINFO were searched from inception to March 2022. Only randomised-controlled trials were included. RESULTS A total of 12 randomised-controlled trials are reviewed for meta-analysis, with three randomised-controlled trials reporting only effects on cognition in psychiatric and cognitively impaired patients, three trials on cognition in healthy subjects, one trial on cognition in both patients and healthy subjects, one trial on only depression, two on both cognition and depression in patients and two on schizophrenia symptoms. No studies were at significant risk of bias. For cognition, TACS showed significant improvement [positive standardised mean differences (SMD) denoting improvement] over sham stimulation in those with psychiatric disorders with an SMD of 0.60 (95% confidence interval [CI]: 0.14, 1.06). Similarly, among patients with depression, an SMD of 1.14 (95% CI: 0.10, 2.18) was found significantly favouring TACS over sham stimulation. Two studies assessed the effect of TACS on schizophrenia symptoms with mixed results. CONCLUSION TACS has shown promise in ameliorating symptoms of both schizophrenia and depression in patients. TACS also improves cognition in both patients and healthy subjects. However, these findings are limited by the sample size of included studies, and future studies may be required to better our understanding of the potential of TACS. REGISTRATION PROSPERO (CRD42022331149).
Collapse
Affiliation(s)
| | - Chun En Yau
- MBBS Programme, Yong Loo Lin School of
Medicine, National University of Singapore, Singapore
| | - Aaron Shengting Mai
- MBBS Programme, Yong Loo Lin School of
Medicine, National University of Singapore, Singapore
| | - Weiling Amanda Tan
- MBBS Programme, Yong Loo Lin School of
Medicine, National University of Singapore, Singapore
| | - Bernard Soon Yang Ong
- MBBS Programme, Yong Loo Lin School of
Medicine, National University of Singapore, Singapore
| | - Natalie Elizabeth Yam
- MBBS Programme, Yong Loo Lin School of
Medicine, National University of Singapore, Singapore
| | - Cyrus Su Hui Ho
- Department of Psychological Medicine, Yong Loo
Lin School of Medicine, National University of Singapore, NUHS Tower Block,
Level 9, 1E Kent Ridge Road, Singapore 119228
| |
Collapse
|
26
|
Zhang DW, Moraidis A, Klingberg T. Individually tuned theta HD-tACS improves spatial performance. Brain Stimul 2022; 15:1439-1447. [PMID: 36328341 DOI: 10.1016/j.brs.2022.10.009] [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: 07/05/2022] [Revised: 10/12/2022] [Accepted: 10/27/2022] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Using transcranial alternating current stimulation (tACS) to improve visuospatial working memory (vsWM) has received considerable attention over the past few years. However, fundamental issues remain, such as the optimal frequency, the generality of behavioral effects, and the anatomical specificity of stimulation. OBJECTIVES Here we examined the effects of two theory-driven tACS protocols for improving vsWM on behavioral and electroencephalogram (EEG) measures. METHODS Twenty adults each completed 3 HD-tACS conditions (Tuned, Slow, and Sham) on two separate days. The Tuned condition refers to a situation in which the frequency of tACS is tuned to individual theta peak measured during a vsWM task. By contrast, the frequency was fixed to 4 Hz in the Slow condition. A high-definition tACS was deployed to target smaller frontal and parietal regions for increasing their phase-locking values. During each tACS condition, participants performed vsWM, mental rotation (MR), and arithmetic tasks. Resting-state EEG (rs-EEG) was recorded before and after each condition. RESULTS Compared with Sham, Tuned but not Slow improved both vsWM and MR but not arithmetics. The rs-EEG recording showed an increased fronto-parietal synchrony for Tuned, and this increase in synchronicity was correlated with the behavioral improvement. A follow-up study showed no behavioral improvement in Tuned with an anti-phase setting. CONCLUSION We provide the first evidence that simulating right fronto-parietal network with the tuned frequency increases the interregional synchronicity and improves performance on two spatial tasks. The results provide insight into the structure of spatial abilities as well as suggestions for stimulating the fronto-parietal network.
Collapse
Affiliation(s)
- Da-Wei Zhang
- Department of Psychology, Yangzhou University, Yangzhou, 225000, China; Department of Neuroscience, Karolinska Institutet, Stockholm, 17177, Sweden.
| | | | - Torkel Klingberg
- Department of Neuroscience, Karolinska Institutet, Stockholm, 17177, Sweden.
| |
Collapse
|
27
|
Varastegan S, Kazemi R, Rostami R, Khomami S, Zandbagleh A, Hadipour AL. Remember NIBS? tACS improves memory performance in elders with subjective memory complaints. GeroScience 2022; 45:851-869. [PMID: 36272055 PMCID: PMC9886712 DOI: 10.1007/s11357-022-00677-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 10/12/2022] [Indexed: 02/03/2023] Open
Abstract
Subjective memory complaints (SMC), the main cognitive component of which is event memory, is a predictor of Alzheimer's disease in elderly people. The purpose of this trial was to investigate the effect of transcranial alternating current stimulation (tACS) with theta frequency (6 Hz) on the medial prefrontal cortex (mPFC) in the improvement of episodic memory in individuals with SMC in a double blind, randomized, and sham-controlled parallel study. Sixteen participants with SMC received either active or sham theta tACS on the mPFC. EEG was recorded, and Rey Auditory Verbal Learning Test (RAVLT) was administered. tACS resulted in a significant improvement in episodic memory performance as measured by RAVLT. EEG data revealed a decrease in theta power; decrease in theta, alpha, and gamma current source density (CSD) in the postcentral, insula, and cingulate gyrus; and decrease in theta and gamma phase synchronization as a result of active tACS, compared to the sham group. Moreover, a significant correlation between delayed recall score of RAVLT and CSD in left inferior gyrus in theta frequency band was observed. The results of the current study showed that theta tACS of the mPFC can improve event memory in individuals with SMC through modulating the activity in the frontal and temporal regions in the brain and thus can be considered a potential therapeutic intervention for this population.
Collapse
Affiliation(s)
| | - Reza Kazemi
- Department of Cognitive Psychology, Institute for Cognitive Science Studies, Blvd Cognitive Science, Pardis, Tehran, 1658344575, Iran.
| | - Reza Rostami
- Department of Psychology, University of Tehran, Tehran, Iran
| | - Sanaz Khomami
- Department of Psychology, Faculty of Education and Psychology, Alzahra University, Tehran, Iran
| | - Ahmad Zandbagleh
- School of Electrical Engineering, Iran University of Science and Technology, Tehran, Iran
| | - Abed L. Hadipour
- Department of Cognitive Sciences, University of Messina, Messina, Italy
| |
Collapse
|
28
|
Bjekić J, Paunovic D, Živanović M, Stanković M, Griskova-Bulanova I, Filipović SR. Determining the Individual Theta Frequency for Associative Memory Targeted Personalized Transcranial Brain Stimulation. J Pers Med 2022; 12:jpm12091367. [PMID: 36143152 PMCID: PMC9506372 DOI: 10.3390/jpm12091367] [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: 06/11/2022] [Revised: 08/05/2022] [Accepted: 08/19/2022] [Indexed: 11/16/2022] Open
Abstract
Non-invasive brain stimulation (NIBS) methods have gained increased interest in research and therapy of associative memory (AM) and its impairments. However, the one-size-fits-all approach yields inconsistent findings, thus putting forward the need for electroencephalography (EEG)-guided personalized frequency-modulated NIBS protocols to increase the focality and the effectiveness of the interventions. Still, extraction of individual frequency, especially in the theta band, turned out to be a challenging task. Here we present an approach to extracting the individual theta-band frequency (ITF) from EEG signals recorded during the AM task. The method showed a 93% success rate, good reliability, and the full range of variability of the extracted ITFs. This paper provides a rationale behind the adopted approach and critically evaluates it in comparison to the alternative methods that have been reported in the literature. Finally, we discuss how it could be used as an input parameter for personalized frequency-modulated NIBS approaches—transcranial alternating current stimulation (tACS) and transcranial oscillatory current stimulation (otDCS) directed at AM neuromodulation.
Collapse
Affiliation(s)
- Jovana Bjekić
- Human Neuroscience Group, Institute for Medical Research, University of Belgrade, 11000 Belgrade, Serbia
- Correspondence: (J.B.); (S.R.F.)
| | - Dunja Paunovic
- Human Neuroscience Group, Institute for Medical Research, University of Belgrade, 11000 Belgrade, Serbia
| | - Marko Živanović
- Institute of Psychology and Laboratory for Research of Individual Differences, Department of Psychology, Faculty of Philosophy, University of Belgrade, 11000 Belgrade, Serbia
| | - Marija Stanković
- Human Neuroscience Group, Institute for Medical Research, University of Belgrade, 11000 Belgrade, Serbia
| | - Inga Griskova-Bulanova
- Institute of Biosciences, Life Sciences Centre, Vilnius University, LT-10322 Vilnius, Lithuania
| | - Saša R. Filipović
- Human Neuroscience Group, Institute for Medical Research, University of Belgrade, 11000 Belgrade, Serbia
- Correspondence: (J.B.); (S.R.F.)
| |
Collapse
|
29
|
Aktürk T, de Graaf TA, Güntekin B, Hanoğlu L, Sack AT. Enhancing memory capacity by experimentally slowing theta frequency oscillations using combined EEG-tACS. Sci Rep 2022; 12:14199. [PMID: 35987918 PMCID: PMC9392784 DOI: 10.1038/s41598-022-18665-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 08/17/2022] [Indexed: 11/09/2022] Open
Abstract
The coupling of gamma oscillation (~ 40+ Hz) amplitude to the phase of ongoing theta (~ 6 Hz) oscillations has been proposed to be directly relevant for memory performance. Current theories suggest that memory capacity scales with number of gamma cycles that can be fitted into the preferred phase of a theta cycle. Following this logic, transcranial alternating current stimulation (tACS) may be used to adjust theta cycles (increasing/decreasing theta frequency) to decrease or increase memory performance during stimulation. Here, we used individualized EEG-informed theta tACS to (1) experimentally “slow down” individual theta frequency (ITF), (2) evaluate cognitive after effects on a battery of memory and learning tasks, and (3) link the cognitive performance changes to tACS-induced effects on theta-band oscillations as measured by post EEG. We found frequency- and task-specific tACS after effects demonstrating a specific enhancement in memory capacity. This tACS-induced cognitive enhancement was specific to the visual memory task performed immediately after tACS offset, and specific to the ITF-1 Hz (slowing) stimulation condition and thus following a protocol specifically designed to slow down theta frequency to enhance memory capacity. Follow-up correlation analyses in this group linked the enhanced memory performance to increased left frontal-parietal theta-band connectivity. Interestingly, resting-state theta power immediately after tACS offset revealed a theta power increase not for the ITF-1 Hz group, but only for the ITF group where the tACS frequency was ‘optimal’ for entrainment. These results suggest that while individually calibrated tACS at peak frequency maximally modulates resting-state oscillatory power, tACS stimulation slightly below this optimal peak theta frequency is better suited to enhance memory capacity performance. Importantly, our results further suggest that such cognitive enhancement effects can last beyond the period of stimulation and are linked to increased network connectivity, opening the door towards more clinical and applied relevance of using tACS in cognitive rehabilitation and/or neurocognitive enhancement.
Collapse
|
30
|
80 Hz but not 40 Hz, transcranial alternating current stimulation of 80 Hz over right intraparietal sulcus increases visuospatial working memory capacity. Sci Rep 2022; 12:13762. [PMID: 35962011 PMCID: PMC9374770 DOI: 10.1038/s41598-022-17965-8] [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: 05/07/2022] [Accepted: 08/03/2022] [Indexed: 11/08/2022] Open
Abstract
Working memory (WM) is a complex cognitive function involved in the temporary storage and manipulation of information, which has been one of the target cognitive functions to be restored in neurorehabilitation. WM capacity is known to be proportional to the number of gamma cycles nested in a single theta cycle. Therefore, gamma-band transcranial alternating current stimulation (tACS) should be dependent of the stimulation frequency; however, the results of previous studies that employed 40 Hz tACS have not been consistent. The optimal locations and injection currents of multiple scalp electrodes were determined based on numerical simulations of electric field. Experiments were conducted with 20 healthy participants. The order of three stimulation conditions (40 Hz tACS, 80 Hz tACS, and sham stimulation) were randomized but counterbalanced. Visual hemifield-specific visual WM capacity was assessed using a delayed visual match to the sample task. High gamma tACS significantly increased WM capacity, while low gamma tACS had no significant effect. Notably, 80 Hz tACS increased WM capacity on both the left and right visual hemifields, while previous tACS studies only reported the effects of tACS on contralateral hemifields. This is the first study to investigate the frequency-dependent effect of gamma-band tACS on WM capacity. Our findings also suggest that high gamma tACS might influence not only WM capacity but also communication between interhemispheric cortical regions. It is expected that high gamma tACS could be a promising neurorehabilitation method to enhance higher-order cognitive functions with similar mechanisms.
Collapse
|
31
|
Local and Distributed fMRI Changes Induced by 40 Hz Gamma tACS of the Bilateral Dorsolateral Prefrontal Cortex: A Pilot Study. Neural Plast 2022; 2022:6197505. [PMID: 35880231 PMCID: PMC9308536 DOI: 10.1155/2022/6197505] [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: 12/14/2021] [Revised: 05/06/2022] [Accepted: 06/21/2022] [Indexed: 11/18/2022] Open
Abstract
Over the past few years, the possibility of modulating fast brain oscillatory activity in the gamma (γ) band through transcranial alternating current stimulation (tACS) has been discussed in the context of both cognitive enhancement and therapeutic scenarios. However, the effects of tACS targeting regions outside the motor cortex, as well as its spatial specificity, are still unclear. Here, we present a concurrent tACS-fMRI block design study to characterize the impact of 40 Hz tACS applied over the left and right dorsolateral prefrontal cortex (DLPFC) in healthy subjects. Results suggest an increase in blood oxygenation level-dependent (BOLD) activity in the targeted bilateral DLPFCs, as well as in surrounding brain areas affected by stimulation according to biophysical modeling, i.e., the premotor cortex and anterior cingulate cortex (ACC). However, off-target effects were also observed, primarily involving the visual cortices, with further effects on the supplementary motor areas (SMA), left subgenual cingulate, and right superior temporal gyrus. The specificity of 40 Hz tACS over bilateral DLPFC and the possibility for network-level effects should be considered in future studies, especially in the context of recently promoted gamma-induction therapeutic protocols for neurodegenerative disorders.
Collapse
|
32
|
Senkowski D, Sobirey R, Haslacher D, Soekadar SR. Boosting working memory: Uncovering the differential effects of tDCS and tACS. Cereb Cortex Commun 2022; 3:tgac018. [PMID: 35592391 PMCID: PMC9113288 DOI: 10.1093/texcom/tgac018] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 04/07/2022] [Accepted: 04/14/2022] [Indexed: 11/12/2022] Open
Abstract
Abstract
Working memory (WM) is essential for reasoning, decision making and problem solving. Recently, there has been an increasing effort in improving WM through non-invasive brain stimulation, especially transcranial direct and alternating current stimulation (tDCS/tACS). Studies suggest that tDCS and tACS can modulate WM performance, but large variability in research approaches hinders identification of optimal stimulation protocols and interpretation of study results. Moreover, it is unclear whether tDCS and tACS differentially affect WM. Here, we summarize and compare studies examining the effects of tDCS and tACS on WM performance in healthy adults. Following PRISMA-selection criteria, our systematic review resulted in 43 studies (29 tDCS, 11 tACS, 3 both) with a total of 1826 adult participants. For tDCS, only 4 out of 23 single-session studies reported effects on WM, while 7 out of 9 multi-session experiments showed positive effects on WM training. For tACS, 10 out of 14 studies demonstrated effects on WM, which were frequency dependent and robust for frontoparietal stimulation. Our review revealed no reliable effect of single-session tDCS on WM, but moderate effects of multi-session tDCS and single-session tACS. We discuss implications of these findings and future directions in the emerging research field of non-invasive brain stimulation and WM.
Collapse
Affiliation(s)
- Daniel Senkowski
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Psychiatry and Neurosciences, Charité Campus Mitte (CCM), Charitéplatz 1, 10117 Berlin
| | - Rabea Sobirey
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Psychiatry and Neurosciences, Charité Campus Mitte (CCM), Charitéplatz 1, 10117 Berlin
| | - David Haslacher
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Psychiatry and Neurosciences, Charité Campus Mitte (CCM), Charitéplatz 1, 10117 Berlin
| | - Surjo R Soekadar
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Psychiatry and Neurosciences, Charité Campus Mitte (CCM), Charitéplatz 1, 10117 Berlin
| |
Collapse
|
33
|
Bjekić J, Živanović M, Paunović D, Vulić K, Konstantinović U, Filipović SR. Personalized Frequency Modulated Transcranial Electrical Stimulation for Associative Memory Enhancement. Brain Sci 2022; 12:472. [PMID: 35448003 PMCID: PMC9025454 DOI: 10.3390/brainsci12040472] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Revised: 03/28/2022] [Accepted: 03/28/2022] [Indexed: 12/25/2022] Open
Abstract
Associative memory (AM) is the ability to remember the relationship between previously unrelated items. AM is significantly affected by normal aging and neurodegenerative conditions, thus there is a growing interest in applying non-invasive brain stimulation (NIBS) techniques for AM enhancement. A growing body of studies identifies posterior parietal cortex (PPC) as the most promising cortical target for both transcranial magnetic stimulation (TMS) and transcranial electrical stimulation (tES) to modulate a cortico-hippocampal network that underlines AM. In that sense, theta frequency oscillatory tES protocols, targeted towards the hallmark oscillatory activity within the cortico-hippocampal network, are increasingly coming to prominence. To increase precision and effectiveness, the need for EEG guided individualization of the tES protocols is proposed. Here, we present the study protocol in which two types of personalized oscillatory tES-transcranial alternating current stimulation (tACS) and oscillatory transcranial direct current stimulation (otDCS), both frequency-modulated to the individual theta-band frequency (ITF), are compared to the non-oscillatory transcranial direct current stimulation (tDCS) and to the sham stimulation. The study has cross-over design with four tES conditions (tACS, otDCS, tDCS, sham), and the comprehensive set of neurophysiological (resting state EEG and AM-evoked EEG) and behavioral outcomes, including AM tasks (short-term associative memory, face-word, face-object, object-location), as well as measures of other cognitive functions (cognitive control, verbal fluency, and working memory).
Collapse
Affiliation(s)
- Jovana Bjekić
- Human Neuroscience Group, Institute for Medical Research, University of Belgrade, Dr Subotica 4, 11000 Belgrade, Serbia; (D.P.); (K.V.); (U.K.); (S.R.F.)
| | - Marko Živanović
- Institute of Psychology and Laboratory for Research of Individual Differences, Department of Psychology, Faculty of Philosophy, University of Belgrade, 11000 Belgrade, Serbia;
| | - Dunja Paunović
- Human Neuroscience Group, Institute for Medical Research, University of Belgrade, Dr Subotica 4, 11000 Belgrade, Serbia; (D.P.); (K.V.); (U.K.); (S.R.F.)
| | - Katarina Vulić
- Human Neuroscience Group, Institute for Medical Research, University of Belgrade, Dr Subotica 4, 11000 Belgrade, Serbia; (D.P.); (K.V.); (U.K.); (S.R.F.)
| | - Uroš Konstantinović
- Human Neuroscience Group, Institute for Medical Research, University of Belgrade, Dr Subotica 4, 11000 Belgrade, Serbia; (D.P.); (K.V.); (U.K.); (S.R.F.)
| | - Saša R. Filipović
- Human Neuroscience Group, Institute for Medical Research, University of Belgrade, Dr Subotica 4, 11000 Belgrade, Serbia; (D.P.); (K.V.); (U.K.); (S.R.F.)
| |
Collapse
|
34
|
Jones KT, Smith CC, Gazzaley A, Zanto TP. Research outside the laboratory: Longitudinal at-home neurostimulation. Behav Brain Res 2022; 428:113894. [DOI: 10.1016/j.bbr.2022.113894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 03/14/2022] [Accepted: 04/11/2022] [Indexed: 11/02/2022]
|
35
|
Wischnewski M, Compen B. Effects of theta transcranial alternating current stimulation (tACS) on exploration and exploitation during uncertain decision-making. Behav Brain Res 2022; 426:113840. [PMID: 35325684 DOI: 10.1016/j.bbr.2022.113840] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 03/02/2022] [Accepted: 03/08/2022] [Indexed: 01/15/2023]
Abstract
Exploring ones surroundings may yield unexpected rewards, but is associated with uncertainty and risk. Alternatively, exploitation of certain outcomes is related to low risk, yet potentially better outcomes remain unexamined. As such, risk-taking behavior depends on perceived uncertainty and a trade-off between exploration-exploitation. Previously, it has been suggested that risk-taking may relate to theta activity in the prefrontal cortex. Furthermore, previous studies hinted at a relationship between a right-hemispheric bias in frontal theta asymmetry and risky behavior. In the present double-blind sham-controlled within-subject study, we applied bifrontal transcranial alternating current stimulation (tACS) at the theta frequency (5 Hz) on eighteen healthy volunteers during a gambling task. Two tACS montages with either left-right or posterior-anterior current flow were employed at an intensity of 1 mA. Results showed that, compared to sham, theta tACS increased perceived uncertainty irrespective of current flow direction. Despite this observation, no direct effect of tACS on exploration behavior and general risk-taking was observed. Furthermore, frontal theta asymmetry was more right-hemispherically biased after posterior-anterior tACS, compared to sham. Finally, we used electric field simulation to identify which regions were targeted by the tACS montages as an overlap in regions may explain why the two montages resulted in comparable outcomes. Our findings provide a first step towards understanding the relationship between frontal theta oscillations and different features of risk-taking.
Collapse
Affiliation(s)
- Miles Wischnewski
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, United States.
| | - Boukje Compen
- School of Health Professions Education, Maastricht University, Maastricht, the Netherlands
| |
Collapse
|
36
|
Zeng L, Guo M, Wu R, Luo Y, Wei P. The Effects of Electroencephalogram Feature-Based Transcranial Alternating Current Stimulation on Working Memory and Electrophysiology. Front Aging Neurosci 2022; 14:828377. [PMID: 35360204 PMCID: PMC8961031 DOI: 10.3389/fnagi.2022.828377] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 02/07/2022] [Indexed: 11/30/2022] Open
Abstract
Transcranial alternating current stimulation (tACS) can influence cognitive functions by modulating brain oscillations. However, results regarding the effectiveness of tACS in regulating cognitive performance have been inconsistent. In the present study, we aimed to find electroencephalogram (EEG) characteristics associated with the improvements in working memory performance, to select tACS stimulus targets and frequency based on this feature, and to explore effects of selected stimulus on verbal working memory. To achieve this goal, we first investigated the EEG characteristics associated with improvements in working memory performance with the aid of EEG analyses and machine learning techniques. These analyses suggested that 8 Hz activity in the prefrontal region was related to accuracy in the verbal working memory task. The tACS stimulus target and pattern were then selected based on the EEG feature. Finally, the selected tACS frequency (8 Hz tACS in the prefrontal region) was applied to modulate working memory. Such modulation resulted significantly greater improvements, compared with 40 Hz and sham modulations (especially for participants with weak verbal working memory). In conclusion, using EEG features related to positive behavioral changes to select brain regions and stimulation patterns for tACS is an effective intervention for improving working memory. Our results contribute to the groundwork for future tACS closed-loop interventions for cognitive deterioration.
Collapse
Affiliation(s)
- Lanting Zeng
- Shenzhen Key Laboratory of Neuropsychiatric Modulation and Collaborative Innovation Center for Brain Science, Guangdong Provincial Key Laboratory of Brain Connectome and Behavior, CAS Center for Excellence in Brain Science and Intelligence Technology, Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen-Hong Kong Institute of Brain Science, Shenzhen Fundamental Research Institutions, Shenzhen, China
| | - Mingrou Guo
- Shenzhen Key Laboratory of Neuropsychiatric Modulation and Collaborative Innovation Center for Brain Science, Guangdong Provincial Key Laboratory of Brain Connectome and Behavior, CAS Center for Excellence in Brain Science and Intelligence Technology, Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen-Hong Kong Institute of Brain Science, Shenzhen Fundamental Research Institutions, Shenzhen, China
| | - Ruoling Wu
- Shenzhen Key Laboratory of Neuropsychiatric Modulation and Collaborative Innovation Center for Brain Science, Guangdong Provincial Key Laboratory of Brain Connectome and Behavior, CAS Center for Excellence in Brain Science and Intelligence Technology, Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen-Hong Kong Institute of Brain Science, Shenzhen Fundamental Research Institutions, Shenzhen, China
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Yu Luo
- Shenzhen Zhongke Huayi Technology Co., Ltd., Shenzhen, China
| | - Pengfei Wei
- Shenzhen Key Laboratory of Neuropsychiatric Modulation and Collaborative Innovation Center for Brain Science, Guangdong Provincial Key Laboratory of Brain Connectome and Behavior, CAS Center for Excellence in Brain Science and Intelligence Technology, Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen-Hong Kong Institute of Brain Science, Shenzhen Fundamental Research Institutions, Shenzhen, China
- University of Chinese Academy of Sciences, Beijing, China
- *Correspondence: Pengfei Wei,
| |
Collapse
|
37
|
Al Qasem W, Abubaker M, Kvašňák E. Working Memory and Transcranial-Alternating Current Stimulation-State of the Art: Findings, Missing, and Challenges. Front Psychol 2022; 13:822545. [PMID: 35237214 PMCID: PMC8882605 DOI: 10.3389/fpsyg.2022.822545] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Accepted: 01/19/2022] [Indexed: 12/06/2022] Open
Abstract
Working memory (WM) is a cognitive process that involves maintaining and manipulating information for a short period of time. WM is central to many cognitive processes and declines rapidly with age. Deficits in WM are seen in older adults and in patients with dementia, schizophrenia, major depression, mild cognitive impairment, Alzheimer's disease, etc. The frontal, parietal, and occipital cortices are significantly involved in WM processing and all brain oscillations are implicated in tackling WM tasks, particularly theta and gamma bands. The theta/gamma neural code hypothesis assumes that retained memory items are recorded via theta-nested gamma cycles. Neuronal oscillations can be manipulated by sensory, invasive- and non-invasive brain stimulations. Transcranial alternating-current stimulation (tACS) and repetitive transcranial magnetic stimulation (rTMS) are frequency-tuned non-invasive brain stimulation (NIBS) techniques that have been used to entrain endogenous oscillations in a frequency-specific manner. Compared to rTMS, tACS demonstrates superior cost, tolerability, portability, and safety profile, making it an attractive potential tool for improving cognitive performance. Although cognitive research with tACS is still in its infancy compared to rTMS, a number of studies have shown a promising WM enhancement effect, especially in the elderly and patients with cognitive deficits. This review focuses on the various methods and outcomes of tACS on WM in healthy and unhealthy human adults and highlights the established findings, unknowns, challenges, and perspectives important for translating laboratory tACS into realistic clinical settings. This will allow researchers to identify gaps in the literature and develop frequency-tuned tACS protocols with promising safety and efficacy outcomes. Therefore, research efforts in this direction should help to consider frequency-tuned tACS as a non-pharmacological tool of cognitive rehabilitation in physiological aging and patients with cognitive deficits.
Collapse
Affiliation(s)
- Wiam Al Qasem
- Department of Medical Biophysics and Medical Informatics, Third Faculty of Medicine, Charles University in Prague, Praha, Czechia
| | | | | |
Collapse
|
38
|
Soleimani G, Kupliki R, Bodurka J, Paulus M, Ekhtiari H. How structural and functional MRI can inform dual-site tACS parameters: A case study in a clinical population and its pragmatic implications. Brain Stimul 2022; 15:337-351. [PMID: 35042056 DOI: 10.1016/j.brs.2022.01.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 01/10/2022] [Accepted: 01/10/2022] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Abnormalities in frontoparietal network (FPN) were observed in many neuropsychiatric diseases including substance use disorders. A growing number of studies are using dual-site-tACS with frontoparietal synchronization to engage this network. However, a computational pathway to inform and optimize parameter space for frontoparietal synchronization is still lacking. In this case study, in a group of participants with methamphetamine use disorders, we proposed a computational pathway to extract optimal electrode montage while accounting for stimulation intensity using structural and functional MRI. METHODS Sixty methamphetamine users completed an fMRI drug cue-reactivity task. Four main steps were taken to define electrode montage and adjust stimulation intensity using 4x1 high-definition (HD) electrodes for a dual-site-tACS; (1) Frontal seed was defined based on the maximum electric fields (EF) predicted by simulation of HD montage over DLPFC (F3/F4 in EEG 10-20), (2) frontal seed-to-whole brain context-dependent correlation was calculated to determine connected regions to frontal seeds, (3) center of connected cluster in parietal cortex was selected as a location for placing the second set of HD electrodes to shape the informed montage, (4) individualized head models were used to determine optimal stimulation intensity considering underlying brain structure. The informed montage was compared to montages with large electrodes and classic frontoparietal HD montages (F3-P3/F4-P4) in terms of tACS-induced EF and ROI-to-ROI task-based/resting-state connectivity. RESULTS Compared to the large electrodes, HD frontoparietal montages allow for a finer control of the spatial peak fields in the main nodes of the FPN at the cost of lower maximum EF (large-pad/HD: max EF[V/m] = 0.37/0.11, number of cortical sub-regions that EF exceeds 50% of the max = 77/13). For defining stimulation targets based on EF patterns, using group-level head models compared to a single standard head model results in comparable but significantly different seed locations (6.43mm Euclidean distance between the locations of the frontal maximum EF in standard-space). As expected, significant task-based/resting-state connections were only found between frontal-parietal locations in the informed montage. Cue-induced craving score was correlated with frontoparietal connectivity only in the informed montage (r = -0.24). Stimulation intensity in the informed montage, and not in the classic HD montage, needs 40% reduction in the parietal site to reduce the disparity in EF between sites. CONCLUSION This study provides some empirical insights to montage and dose selection in dual-site-tACS using individual brain structures and functions and proposes a computational pathway to use head models and functional MRI to define (1) optimum electrode montage for targeting FPN in a context of interest (drug-cue-reactivity) and (2) proper transcranial stimulation intensity.
Collapse
Affiliation(s)
- Ghazaleh Soleimani
- Department of Biomedical Engineering, Amirkabir University of Technology, Tehran, Iran; Iranian National Center for Addiction Studies, Tehran University of Medical Sciences, Tehran, Iran
| | - Rayus Kupliki
- Laureate Institute for Brain Research, Tulsa, OK, United States
| | - Jerzy Bodurka
- Laureate Institute for Brain Research, Tulsa, OK, United States
| | - Martin Paulus
- Laureate Institute for Brain Research, Tulsa, OK, United States
| | - Hamed Ekhtiari
- Laureate Institute for Brain Research, Tulsa, OK, United States.
| |
Collapse
|
39
|
Rezayat E, Clark K, Dehaqani MRA, Noudoost B. Dependence of Working Memory on Coordinated Activity Across Brain Areas. Front Syst Neurosci 2022; 15:787316. [PMID: 35095433 PMCID: PMC8792503 DOI: 10.3389/fnsys.2021.787316] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 12/06/2021] [Indexed: 11/15/2022] Open
Abstract
Neural signatures of working memory (WM) have been reported in numerous brain areas, suggesting a distributed neural substrate for memory maintenance. In the current manuscript we provide an updated review of the literature focusing on intracranial neurophysiological recordings during WM in primates. Such signatures of WM include changes in firing rate or local oscillatory power within an area, along with measures of coordinated activity between areas based on synchronization between oscillations. In comparing the ability of various neural signatures in any brain area to predict behavioral performance, we observe that synchrony between areas is more frequently and robustly correlated with WM performance than any of the within-area neural signatures. We further review the evidence for alteration of inter-areal synchrony in brain disorders, consistent with an important role for such synchrony during behavior. Additionally, results of causal studies indicate that manipulating synchrony across areas is especially effective at influencing WM task performance. Each of these lines of research supports the critical role of inter-areal synchrony in WM. Finally, we propose a framework for interactions between prefrontal and sensory areas during WM, incorporating a range of experimental findings and offering an explanation for the observed link between intra-areal measures and WM performance.
Collapse
Affiliation(s)
- Ehsan Rezayat
- School of Cognitive Sciences, Institute for Research in Fundamental Sciences (IPM), Tehran, Iran
| | - Kelsey Clark
- Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, UT, United States
| | - Mohammad-Reza A. Dehaqani
- School of Cognitive Sciences, Institute for Research in Fundamental Sciences (IPM), Tehran, Iran
- Cognitive Systems Laboratory, Control and Intelligent Processing Center of Excellence (CIPCE), School of Electrical and Computer Engineering, College of Engineering, University of Tehran, Tehran, Iran
| | - Behrad Noudoost
- Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, UT, United States
- *Correspondence: Behrad Noudoost,
| |
Collapse
|
40
|
Booth SJ, Taylor JR, Brown LJE, Pobric G. The effects of transcranial alternating current stimulation on memory performance in healthy adults: A systematic review. Cortex 2021; 147:112-139. [PMID: 35032750 DOI: 10.1016/j.cortex.2021.12.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 11/14/2021] [Accepted: 12/01/2021] [Indexed: 01/03/2023]
Abstract
The recent introduction of Transcranial Alternating Current stimulation (tACS) in research on memory modulation has yielded some exciting findings. Whilst evidence suggests small but significant modulatory effects of tACS on perception and cognition, it is unclear how effective tACS is at modulating memory, and the neural oscillations underlying memory. The aim of this systematic review was to determine the efficacy with which tACS, compared to sham stimulation, can modify working memory (WM) and long-term memory (LTM) performance in healthy adults. We examined how these effects may be moderated by specific tACS parameters and study/participant characteristics. Our secondary goal was to investigate the neural correlates of tACS' effects on memory performance in healthy adults. A systematic search of eight databases yielded 11,413 records, resulting in 34 papers that included 104 eligible studies. The results were synthesised by memory type (WM/LTM) and according to the specific parameters of frequency band, stimulation montage, individual variability, cognitive demand, and phase. A second synthesis examined the correspondence between tACS' effects on memory performance and the oscillatory features of electroencephalography (EEG) and magnetencephalography (MEG) recordings in a subset of 26 studies. The results showed a small-to-medium effect of tACS on WM and LTM performance overall. There was strong evidence to suggest that posterior theta-tACS modulates WM performance, whilst the modulation of LTM is achieved by anterior gamma-tACS. Moreover, there was a correspondence between tACS effects on memory performance and oscillatory outcomes at the stimulation frequency. We discuss limitations in the field and suggest ways to improve our understanding of tACS efficacy to ensure a transition of tACS from an investigative method to a therapeutic tool.
Collapse
Affiliation(s)
- Samantha J Booth
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine, and Health, University of Manchester, Manchester Academic Health Science Centre, England, UK.
| | - Jason R Taylor
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine, and Health, University of Manchester, Manchester Academic Health Science Centre, England, UK.
| | - Laura J E Brown
- Division of Psychology and Mental Health, School of Health Sciences, Faculty of Biology, Medicine, and Health, University of Manchester, Manchester Academic Health Science Centre, England, UK.
| | - Gorana Pobric
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine, and Health, University of Manchester, Manchester Academic Health Science Centre, England, UK.
| |
Collapse
|
41
|
Behavioral and electrocortical effects of transcranial alternating current stimulation during advice-guided decision-making. NEUROIMAGE: REPORTS 2021. [DOI: 10.1016/j.ynirp.2021.100052] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
42
|
The Modulation of Working-Memory Performance Using Gamma-Electroacupuncture and Theta-Electroacupuncture in Healthy Adults. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2021; 2021:2062718. [PMID: 34824588 PMCID: PMC8610651 DOI: 10.1155/2021/2062718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/17/2021] [Revised: 10/07/2021] [Accepted: 10/26/2021] [Indexed: 11/17/2022]
Abstract
Working memory (WM), a central component of general cognition, plays an essential role in human beings' daily lives. WM impairments often occur in psychiatric, neurodegenerative, and neurodevelopmental disorders, mainly presenting as loss of high-load WM. In previous research, electroacupuncture (EA) has been shown to be an effective treatment for cognitive impairments. Frequency parameters are an important factor in therapeutic results, but the optimal frequency parameters of EA have not yet been identified. In this study, we chose theta-EA (θ-EA; 6 Hz) and gamma-EA (γ-EA; 40 Hz), corresponding to the transcranial alternating-current stimulation (tACS) frequency parameters at the Baihui (DU20) and Shenting (DU24) acupoints, in order to compare the effects of different EA frequencies on WM. We evaluated WM performance using visual 1-back, 2-back, and 3-back WM tasks involving digits. Each participant (N = 30) attended three different sessions in accordance with a within-subject crossover design. We performed θ-EA, γ-EA, and sham-EA in a counterbalanced order, conducting the WM task both before and after intervention. The results showed that d-prime (d′) under all three stimulation conditions had no significance in the 1-back and 2-back tasks. However, in the 3-back task, there was a significant improvement in d′ after intervention compared to d′ before intervention under θ-EA (F [1, 29] = 22.64; P < 0.001), while we saw no significant difference in the γ-EA and sham-EA groups. Reaction times for hits (RT-hit) under all three stimulation conditions showed decreasing trends in 1-, 2-, and 3-back tasks but without statistically significant differences. These findings suggest that the application of θ-EA might facilitate high-load WM performance.
Collapse
|
43
|
Mosbacher JA, Halverscheid S, Pustelnik K, Danner M, Prassl C, Brunner C, Vogel SE, Nitsche MA, Grabner RH. Theta Band Transcranial Alternating Current Stimulation Enhances Arithmetic Learning: A Systematic Comparison of Different Direct and Alternating Current Stimulations. Neuroscience 2021; 477:89-105. [PMID: 34648868 DOI: 10.1016/j.neuroscience.2021.10.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 10/01/2021] [Accepted: 10/04/2021] [Indexed: 11/17/2022]
Abstract
Over the last decades, interest in transcranial electrical stimulation (tES) has grown, as it might allow for causal investigations of the associations between cortical activity and cognition as well as to directly influence cognitive performance. The main objectives of the present work were to assess whether tES can enhance the acquisition and application of arithmetic abilities, and whether it enables a better assessment of underlying neurophysiological processes. To this end, the present, double-blind, sham-controlled study assessed the effects of six active stimulations (three tES protocols: anodal transcranial direct current stimulation (tDCS), alpha band transcranial alternating current stimulation (tACS), and theta band tACS; targeting the left dorsolateral prefrontal cortex or the left posterior parietal cortex) on the acquisition of an arithmetic procedure, arithmetic facts, and event-related synchronization/desynchronization (ERS/ERD) patterns. 137 healthy adults were randomly assigned to one of seven groups, each receiving one of the tES-protocols during learning. Results showed that frontal theta band tACS reduced the repetitions needed to learn novel facts and both, frontal and parietal theta band tACS accelerated the decrease in calculation times in fact learning problems. The beneficial effect of frontal theta band tACS may reflect enhanced executive functions, allowing for better control and inhibition processes and hence, a faster acquisition and integration of novel fact knowledge. However, there were no significant effects of the stimulations on procedural learning or ERS/ERD patterns. Overall, theta band tACS appears promising as a support for arithmetic fact training, but effects on procedural calculations and neurophysiological processes remain ambiguous.
Collapse
Affiliation(s)
- Jochen A Mosbacher
- Section of Educational Neuroscience, Institute of Psychology, University of Graz, Graz, Austria.
| | | | - Kolja Pustelnik
- Mathematics Institute, University of Göttingen, Göttingen, Germany
| | - Martina Danner
- Section of Educational Neuroscience, Institute of Psychology, University of Graz, Graz, Austria
| | - Christina Prassl
- Section of Educational Neuroscience, Institute of Psychology, University of Graz, Graz, Austria
| | - Clemens Brunner
- Section of Educational Neuroscience, Institute of Psychology, University of Graz, Graz, Austria
| | - Stephan E Vogel
- Section of Educational Neuroscience, Institute of Psychology, University of Graz, Graz, Austria
| | - Michael A Nitsche
- Department of Psychology and Neurosciences, Leibniz Research Centre for Working Environment and Human Factors, Dortmund, Germany; Department of Neurology, University Medical Hospital Bergmannsheil, Ruhr-University Bochum, Bochum, Germany
| | - Roland H Grabner
- Section of Educational Neuroscience, Institute of Psychology, University of Graz, Graz, Austria; BioTechMed Graz, Graz, Austria
| |
Collapse
|
44
|
Sahu PP, Tseng P. Frontoparietal theta tACS nonselectively enhances encoding, maintenance, and retrieval stages in visuospatial working memory. Neurosci Res 2021; 172:41-50. [PMID: 33992662 DOI: 10.1016/j.neures.2021.05.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 04/21/2021] [Accepted: 05/06/2021] [Indexed: 11/30/2022]
Abstract
Neurobiological and cognitive evidence suggests that working memory is processed through three distinctive and well-characterized phases: encoding, maintenance, and retrieval. Several studies have reported that applying theta transcranial alternating current stimulation (tACS) to the right prefrontal and parietal cortices can significantly improve visual working memory performance. However, it remains unclear whether the facilitative effect of tACS on visual working memory is due to a domain-general or stage-specific process. In this study, we combined pre-task right frontoparietal theta tACS (6 Hz, 15 min) with a stage-specific change detection paradigm that provided retro-cues during various stages of working memory. This stage-specific tagging via the use of retro-cues enabled us to probe whether theta tACS would create a nonspecific/additive effect that is equal in magnitude across all cognitive stages or would create a stage-specific effect that is interactive with the retro-cue in a particular stage (e.g., maintenance, retrieval). We observed significant retro-cue and theta tACS effects on visual working memory performance, but no interaction between them. This finding suggests that the aforementioned two factors can facilitate visual working memory processing independently in an additive manner. Furthermore, low-performers benefited more from tACS, and their VWM deficit seemed to have originated from the second half of the memory retention stage, which possibly suggests faster memory decay as the key to poor VWM performance. Together, we conclude that frontoparietal theta tACS likely creates a domain-general boost in visual attention, which in turn benefits overall visual working memory processes that are not specific to the information maintenance or retrieval stages.
Collapse
Affiliation(s)
- Prangya Parimita Sahu
- Graduate Institute of Mind, Brain, & Consciousness, College of Humanities and Social Sciences, Taipei Medical University, Taipei, Taiwan
| | - Philip Tseng
- Graduate Institute of Mind, Brain, & Consciousness, College of Humanities and Social Sciences, Taipei Medical University, Taipei, Taiwan; Brain and Consciousness Research Center, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan; Psychiatric Research Center, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan.
| |
Collapse
|
45
|
Haque ZZ, Samandra R, Mansouri FA. Neural substrate and underlying mechanisms of working memory: insights from brain stimulation studies. J Neurophysiol 2021; 125:2038-2053. [PMID: 33881914 DOI: 10.1152/jn.00041.2021] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The concept of working memory refers to a collection of cognitive abilities and processes involved in the short-term storage of task-relevant information to guide the ongoing and upcoming behavior and therefore describes an important aspect of executive control of behavior for achieving goals. Deficits in working memory and related cognitive abilities have been observed in patients with brain damage or neuropsychological disorders and therefore it is important to better understand neural substrate and underlying mechanisms of working memory. Working memory relies on neural mechanisms that enable encoding, maintenance, and manipulation of stored information as well as integrating them with ongoing and future goals. Recently, a surge in brain stimulation studies have led to development of various noninvasive techniques for localized stimulation of prefrontal and other cortical regions in humans. These brain stimulation techniques can potentially be tailored to influence neural activities in particular brain regions and modulate cognitive functions and behavior. Combined use of brain stimulation with neuroimaging and electrophysiological recording have provided a great opportunity to monitor neural activity in various brain regions and noninvasively intervene and modulate cognitive functions in cognitive tasks. These studies have shed more light on the neural substrate and underlying mechanisms of working memory in humans. Here, we review findings and insight from these brain stimulation studies about the contribution of brain regions, and particularly prefrontal cortex, to working memory.
Collapse
Affiliation(s)
- Zakia Z Haque
- Cognitive Neuroscience Laboratory, Department of Physiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Ranshikha Samandra
- Cognitive Neuroscience Laboratory, Department of Physiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Farshad Alizadeh Mansouri
- Cognitive Neuroscience Laboratory, Department of Physiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia.,ARC Centre for Integrative Brain Function, Monash University, Clayton, Victoria, Australia
| |
Collapse
|
46
|
Klírová M, Voráčková V, Horáček J, Mohr P, Jonáš J, Dudysová DU, Kostýlková L, Fayette D, Krejčová L, Baumann S, Laskov O, Novák T. Modulating Inhibitory Control Processes Using Individualized High Definition Theta Transcranial Alternating Current Stimulation (HD θ-tACS) of the Anterior Cingulate and Medial Prefrontal Cortex. Front Syst Neurosci 2021; 15:611507. [PMID: 33859554 PMCID: PMC8042221 DOI: 10.3389/fnsys.2021.611507] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 03/04/2021] [Indexed: 02/02/2023] Open
Abstract
Increased frontal midline theta activity generated by the anterior cingulate cortex (ACC) is induced by conflict processing in the medial frontal cortex (MFC). There is evidence that theta band transcranial alternating current stimulation (θ-tACS) modulates ACC function and alters inhibitory control performance during neuromodulation. Multi-electric (256 electrodes) high definition θ-tACS (HD θ-tACS) using computational modeling based on individual MRI allows precise neuromodulation targeting of the ACC via the medial prefrontal cortex (mPFC), and optimizes the required current density with a minimum impact on the rest of the brain. We therefore tested whether the individualized electrode montage of HD θ-tACS with the current flow targeted to the mPFC-ACC compared with a fixed montage (non-individualized) induces a higher post-modulatory effect on inhibitory control. Twenty healthy subjects were randomly assigned to a sequence of three HD θ-tACS conditions (individualized mPFC-ACC targeting; non-individualized MFC targeting; and a sham) in a double-blind cross-over study. Changes in the Visual Simon Task, Stop Signal Task, CPT III, and Stroop test were assessed before and after each session. Compared with non-individualized θ-tACS, the individualized HD θ-tACS significantly increased the number of interference words and the interference score in the Stroop test. The changes in the non-verbal cognitive tests did not induce a parallel effect. This is the first study to examine the influence of individualized HD θ-tACS targeted to the ACC on inhibitory control performance. The proposed algorithm represents a well-tolerated method that helps to improve the specificity of neuromodulation targeting of the ACC.
Collapse
Affiliation(s)
- Monika Klírová
- National Institute of Mental Health, Prague, Czechia
- Department of Psychiatry, Third Faculty of Medicine, Charles University, Prague, Czechia
| | - Veronika Voráčková
- National Institute of Mental Health, Prague, Czechia
- Department of Psychiatry, Third Faculty of Medicine, Charles University, Prague, Czechia
| | - Jiří Horáček
- National Institute of Mental Health, Prague, Czechia
- Department of Psychiatry, Third Faculty of Medicine, Charles University, Prague, Czechia
| | - Pavel Mohr
- National Institute of Mental Health, Prague, Czechia
- Department of Psychiatry, Third Faculty of Medicine, Charles University, Prague, Czechia
| | - Juraj Jonáš
- National Institute of Mental Health, Prague, Czechia
| | - Daniela Urbaczka Dudysová
- National Institute of Mental Health, Prague, Czechia
- Department of Psychiatry, Third Faculty of Medicine, Charles University, Prague, Czechia
| | - Lenka Kostýlková
- National Institute of Mental Health, Prague, Czechia
- Department of Psychiatry, Third Faculty of Medicine, Charles University, Prague, Czechia
| | - Dan Fayette
- National Institute of Mental Health, Prague, Czechia
- Department of Psychiatry, Third Faculty of Medicine, Charles University, Prague, Czechia
| | | | | | - Olga Laskov
- National Institute of Mental Health, Prague, Czechia
- Department of Psychiatry, Third Faculty of Medicine, Charles University, Prague, Czechia
| | - Tomáš Novák
- National Institute of Mental Health, Prague, Czechia
- Department of Psychiatry, Third Faculty of Medicine, Charles University, Prague, Czechia
| |
Collapse
|
47
|
Krebs C, Peter J, Wyss P, Brem AK, Klöppel S. Transcranial electrical stimulation improves cognitive training effects in healthy elderly adults with low cognitive performance. Clin Neurophysiol 2021; 132:1254-1263. [PMID: 33875372 DOI: 10.1016/j.clinph.2021.01.034] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 11/25/2020] [Accepted: 01/25/2021] [Indexed: 11/15/2022]
Abstract
OBJECTIVE To investigate the efficacy of transcranial direct (tDCS) or alternating current stimulation (tACS) in boosting cognitive training efficiency in healthy older adults. We further explored whether such improvements depend on general cognitive performance or age. METHODS In this randomized, sham-controlled study, 59 healthy elderly participants (mean age 71.7) were assigned to receive computer-based cognitive training (10 sessions, 50 min, twice weekly) combined with tDCS (2 mA), tACS (5 Hz), or sham stimulation over the left dorsolateral prefrontal cortex (20 minutes). Cognitive performance was assessed with the Montreal Cognitive Assessment (MoCA), and a cognitive composite score derived from a broad neuropsychological test battery before and immediately after the intervention as well as at 6 and 12 months follow-ups. RESULTS Performance in the cognitive composite score improved significantly in all groups but was not further modulated by neurostimulation. Additional analyses revealed that participants with a low initial MoCA score (<1SD) improved significantly more in the tDCS than in the sham group. CONCLUSION TDCS increased the efficacy of cognitive training, but only in participants with initially low general cognitive performance. SIGNIFICANCE Cognitive interventions including tDCS should address baseline performance as modulating factor of cognitive outcomes.
Collapse
Affiliation(s)
- Christine Krebs
- University Hospital of Old Age Psychiatry and Psychotherapy, University of Bern, Bern, Switzerland; Graduate School for Health Sciences, University of Bern, Bern, Switzerland.
| | - Jessica Peter
- University Hospital of Old Age Psychiatry and Psychotherapy, University of Bern, Bern, Switzerland
| | - Patric Wyss
- University Hospital of Old Age Psychiatry and Psychotherapy, University of Bern, Bern, Switzerland
| | - Anna-Katharine Brem
- University Hospital of Old Age Psychiatry and Psychotherapy, University of Bern, Bern, Switzerland; Department of Neuropsychology, Lucerne Psychiatry, Lucerne, Switzerland; Berenson-Allen Center for Noninvasive Brain Stimulation, Division of Cognitive Neurology, Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States
| | - Stefan Klöppel
- University Hospital of Old Age Psychiatry and Psychotherapy, University of Bern, Bern, Switzerland
| |
Collapse
|
48
|
Benussi A, Cantoni V, Cotelli MS, Cotelli M, Brattini C, Datta A, Thomas C, Santarnecchi E, Pascual-Leone A, Borroni B. Exposure to gamma tACS in Alzheimer's disease: A randomized, double-blind, sham-controlled, crossover, pilot study. Brain Stimul 2021; 14:531-540. [PMID: 33762220 DOI: 10.1016/j.brs.2021.03.007] [Citation(s) in RCA: 58] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 03/05/2021] [Accepted: 03/11/2021] [Indexed: 12/12/2022] Open
Abstract
OBJECTIVE To assess whether exposure to non-invasive brain stimulation with transcranial alternating current stimulation at γ frequency (γ-tACS) applied over Pz (an area overlying the medial parietal cortex and the precuneus) can improve memory and modulate cholinergic transmission in mild cognitive impairment due to Alzheimer's disease (MCI-AD). METHODS In this randomized, double-blind, sham controlled, crossover pilot study, participants were assigned to a single 60 min treatment with exposure to γ-tACS over Pz or sham tACS. Each subject underwent a clinical evaluation including assessment of episodic memory pre- and post-γ-tACS or sham stimulation. Indirect measures of cholinergic transmission evaluated using transcranial magnetic stimulation (TMS) pre- and post-γ-tACS or sham tACS were evaluated. RESULTS Twenty MCI-AD participants completed the study. No tACS-related side effects were observed, and the intervention was well tolerated in all participants. We observed a significant improvement at the Rey auditory verbal learning (RAVL) test total recall (5.7 [95% CI, 4.0 to 7.4], p < 0.001) and long delayed recall scores (1.3 [95% CI, 0.4 to 2.1], p = 0.007) after γ-tACS but not after sham tACS. Face-name associations scores improved during γ-tACS (4.3 [95% CI, 2.8 to 5.8], p < 0.001) but not after sham tACS. Short latency afferent inhibition, an indirect measure of cholinergic transmission evaluated with TMS, increased only after γ-tACS (0.31 [95% CI, 0.24 to 0.38], p < 0.001) but not after sham tACS. CONCLUSIONS exposure to γ-tACS over Pz showed a significant improvement of memory performances, along with restoration of intracortical connectivity measures of cholinergic neurotransmission, compared to sham tACS.
Collapse
Affiliation(s)
- Alberto Benussi
- Neurology Unit, Department of Clinical and Experimental Sciences, University of Brescia, Brescia, Italy; Neurology Unit, Department of Neurological and Vision Sciences, ASST Spedali Civili, Brescia, Italy
| | - Valentina Cantoni
- Neurology Unit, Department of Clinical and Experimental Sciences, University of Brescia, Brescia, Italy
| | | | - Maria Cotelli
- Neuropsychology Unit, IRCCS Istituto Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy
| | - Chiara Brattini
- Neurology Unit, Department of Neurological and Vision Sciences, ASST Spedali Civili, Brescia, Italy
| | - Abhishek Datta
- Research & Development, Soterix Medical, Inc., New York, USA
| | - Chris Thomas
- Research & Development, Soterix Medical, Inc., New York, USA
| | - Emiliano Santarnecchi
- Berenson-Allen Center for Non-Invasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA; Department of Neurology, Harvard Medical School, Boston, MA, USA
| | - Alvaro Pascual-Leone
- Department of Neurology, Harvard Medical School, Boston, MA, USA; Hinda and Arthur Marcus Institute for Aging Research and Center for Memory Health, Hebrew SeniorLife, Boston, MA, USA; Guttmann Brain Health Institut, Institut Guttmann, Universitat Autonoma Barcelona, Spain
| | - Barbara Borroni
- Neurology Unit, Department of Clinical and Experimental Sciences, University of Brescia, Brescia, Italy; Neurology Unit, Department of Neurological and Vision Sciences, ASST Spedali Civili, Brescia, Italy.
| |
Collapse
|
49
|
Ergo K, De Loof E, Debra G, Pastötter B, Verguts T. Failure to modulate reward prediction errors in declarative learning with theta (6 Hz) frequency transcranial alternating current stimulation. PLoS One 2020; 15:e0237829. [PMID: 33270685 PMCID: PMC7714179 DOI: 10.1371/journal.pone.0237829] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 11/18/2020] [Indexed: 12/26/2022] Open
Abstract
Recent evidence suggests that reward prediction errors (RPEs) play an important role in declarative learning, but its neurophysiological mechanism remains unclear. Here, we tested the hypothesis that RPEs modulate declarative learning via theta-frequency oscillations, which have been related to memory encoding in prior work. For that purpose, we examined the interaction between RPE and transcranial Alternating Current Stimulation (tACS) in declarative learning. Using a between-subject (real versus sham stimulation group), single-blind stimulation design, 76 participants learned 60 Dutch-Swahili word pairs, while theta-frequency (6 Hz) tACS was administered over the medial frontal cortex (MFC). Previous studies have implicated MFC in memory encoding. We replicated our previous finding of signed RPEs (SRPEs) boosting declarative learning; with larger and more positive RPEs enhancing memory performance. However, tACS failed to modulate the SRPE effect in declarative learning and did not affect memory performance. Bayesian statistics supported evidence for an absence of effect. Our study confirms a role of RPE in declarative learning, but also calls for standardized procedures in transcranial electrical stimulation.
Collapse
Affiliation(s)
- Kate Ergo
- Department of Experimental Psychology, Ghent University, Ghent, Belgium
| | - Esther De Loof
- Department of Experimental Psychology, Ghent University, Ghent, Belgium
| | - Gillian Debra
- Department of Experimental Psychology, Ghent University, Ghent, Belgium
| | | | - Tom Verguts
- Department of Experimental Psychology, Ghent University, Ghent, Belgium
| |
Collapse
|
50
|
Xu JJ, Ren M, Zhao JJ, Wu JJ, Zhang SC, Zhong YB, Xu ST, Cao ZY, Zhou ZQ, Li YL, Shan CL. Effectiveness of theta and gamma electroacupuncture for post-stroke patients on working memory and electrophysiology: study protocol for a double-center, randomized, patient- and assessor-blinded, sham-controlled, parallel, clinical trial. Trials 2020; 21:910. [PMID: 33148333 PMCID: PMC7641837 DOI: 10.1186/s13063-020-04807-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 10/16/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Practitioners of complementary and alternative medicine have suggested that electroacupuncture (EA) could improve post-stroke cognitive impairment, based on the clinical evidence. This study protocol is aimed at showing the effectiveness of theta and gamma EA for post-stroke patients on working memory (WM) and electrophysiology. METHODS After assessing their eligibility, 66 patients with stroke will be enrolled from two Chinese medicine hospitals and randomly divided into theta frequency EA group, gamma frequency EA group, and sham-EA group according to the ratio of 1:1:1. All patients will receive 20 sessions of EA procedures for 4 weeks. Patients in three groups will receive EA at two same acupoints in the head: Baihui (GV20) and Shenting (GV24). The frequency of the three groups of EA is set as follows: 6 Hz (theta-EA group), 40 Hz (gamma-EA group), and no current through the electrodes (sham EA). Patients and assessors will be blinded throughout the entire study. The primary outcome is the performance accuracy of 1-back task which is a frequently used measure of WM in cognitive neuroscience research contexts. Secondary outcome measures will include the response time of 1-back task, the Rivermead Behavioral Memory Test, Trail Making Test, Loewenstein Occupational Therapy Cognitive Assessment Scale, modified Barthel Index, and electroencephalogram (EEG) signals during 1-back tasks. A blinding index will be assessed. Data will be statistically analyzed by one-way ANOVA, at 5% of significance level. DISCUSSION We expect this double-center, randomized, patient- and assessor-blinded, sham-controlled, parallel, clinical trial to explore the effectiveness of theta and gamma EA therapy, compared with sham EA, for post-stroke WM. TRIAL REGISTRATION Chinese Clinical Trial Registry, ChiCTR2000031995 . Registered on 17 April 2020.
Collapse
Affiliation(s)
- Jing-Jing Xu
- Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, 110 Ganhe Road, Hongkou District, Shanghai, 200000, China.,Shanghai University of Traditional Chinese Medicine, 1200 Cailun Road, Pudong New District, Shanghai, 200000, China
| | - Meng Ren
- Shanghai University of Traditional Chinese Medicine, 1200 Cailun Road, Pudong New District, Shanghai, 200000, China
| | - Jing-Jun Zhao
- Shanghai University of Traditional Chinese Medicine, 1200 Cailun Road, Pudong New District, Shanghai, 200000, China
| | - Jia-Jia Wu
- Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, 110 Ganhe Road, Hongkou District, Shanghai, 200000, China
| | - Si-Cong Zhang
- Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, 110 Ganhe Road, Hongkou District, Shanghai, 200000, China
| | - Yan-Biao Zhong
- Shanghai University of Traditional Chinese Medicine, 1200 Cailun Road, Pudong New District, Shanghai, 200000, China
| | - Shu-Tian Xu
- Shanghai University of Traditional Chinese Medicine, 1200 Cailun Road, Pudong New District, Shanghai, 200000, China
| | - Zhong-Yao Cao
- Anhui Wannan Rehabilitation Hospital, 3 Zheshang road, Jinghu District, Wuhu City, 241000, Anhui Province, China
| | - Zhi-Qing Zhou
- Shanghai University of Traditional Chinese Medicine, 1200 Cailun Road, Pudong New District, Shanghai, 200000, China
| | - Yuan-Li Li
- Shanghai University of Traditional Chinese Medicine, 1200 Cailun Road, Pudong New District, Shanghai, 200000, China.
| | - Chun-Lei Shan
- Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, 110 Ganhe Road, Hongkou District, Shanghai, 200000, China. .,Shanghai University of Traditional Chinese Medicine, 1200 Cailun Road, Pudong New District, Shanghai, 200000, China.
| |
Collapse
|