BACKGROUND Working memory serves as a fundamental cognitive function that substantially impacts performance in various cognitive tasks.Extensive neurophysiological research has established that theta oscillations(4-8 ...BACKGROUND Working memory serves as a fundamental cognitive function that substantially impacts performance in various cognitive tasks.Extensive neurophysiological research has established that theta oscillations(4-8 Hz)play an essential role in supporting working memory operations.Theta-band transcranial alternating current stimulation(tACS)offers a potential mechanism for working memory enhancement through direct modulation of these fundamental neural oscillations.Nevertheless,current empirical evidence shows substantial variability in the observed effects of theta-tACS across studies.AIM To conduct a systematic review and meta-analysis evaluating the effects of thetatACS on working memory performance in healthy adults.METHODS A systematic literature search was performed on PubMed,EMBASE,and Web of Science up to March 10,2025.Effect sizes were computed using Hedges’g with 95%confidence intervals(CIs),with separate meta-analyses for all included studies and for distinct working memory paradigms[n-back and delayed matchto-sample(DMTS)tasks]to examine potential task-specific effects.Subgroup analyses and meta-regression were performed to evaluate the influence of key moderating variables.RESULTS The systematic review included 21 studies(67 effect sizes).Initial meta-analysis showed theta-tACS moderately improved working memory(Hedges’g=0.405,95%CI:0.212-0.598).However,this effect became nonsignificant after correcting for publication bias(trim-and-fill adjusted Hedges’g=0.082,95%CI:-0.052 to 0.217).Task-specific analyses revealed significant benefits in n-back tasks(Hedges’g=0.463,95%CI:0.193-0.733)but not in DMTS tasks(Hedges’g=0.257,95%CI:-0.186 to 0.553).Moderator analyses showed that performance in n-back tasks was influenced by stimulation frequency(P=0.001),concurrent status(P=0.014),task modality(P=0.005),and duration(P=0.013),whereas only the region of targeted stimulation(P=0.012)moderated DMTS tasks.CONCLUSION Theta-tACS enhances working memory in healthy adults,with effects modulated by the task type and protocol parameters,offering dual implications for cognitive enhancement and clinical interventions.展开更多
For decades visual field defects were considered irreversible because it was thought that in the visual system the regeneration potential of the neuronal tissues is low.Nevertheless,there is always some potential for ...For decades visual field defects were considered irreversible because it was thought that in the visual system the regeneration potential of the neuronal tissues is low.Nevertheless,there is always some potential for partial recovery of the visual field defect that can be achieved through induction of neuroplasticity.Neuroplasticity refers to the ability of the brain to change its own functional architecture by modulating synaptic efficacy.It is maintained throughout life and just as neurological rehabilitation can improve motor coordination,visual field defects in glaucoma,diabetic retinopathy or optic neuropathy can be improved by inducing neuroplasticity.In ophthalmology many new treatment paradigms have been tested that can induce neuroplastic changes,including non-invasive alternating current stimulation.Treatment with alternating current stimulation(e.g.,30 minutes,daily for 10 days using transorbital electrodes and^10 Hz)activates the entire retina and parts of the brain.Electroencephalography and functional magnetic resonance imaging studies revealed local activation of the visual cortex,global reorganization of functional brain networks,and enhanced blood flow,which together activate neurons and their networks.The future of low vision is optimistic because vision loss is indeed,partially reversible.展开更多
Transcranial alternating current stimulation(tACS)is a noninvasive neuromodulation technique that regulates brain function by applying sinusoidal alternating currents of specific frequencies to targeted brain regions ...Transcranial alternating current stimulation(tACS)is a noninvasive neuromodulation technique that regulates brain function by applying sinusoidal alternating currents of specific frequencies to targeted brain regions through the scalp electrodes.[1]This guideline aims to evaluate and summarize the efficacy and safety of tACS in clinical applications.We conducted a structured literature search across major databases using the terms“tACS”or“transcranial alternating current stimulation”to identify all relevant literature up to June 2022.展开更多
Background:Transcranial alternating current stimulation(tACS)offers a new approach for adult patients with major depressive disorder(MDD).The study is to evaluate the efficacy and safety of tACS treating MDD.Methods:T...Background:Transcranial alternating current stimulation(tACS)offers a new approach for adult patients with major depressive disorder(MDD).The study is to evaluate the efficacy and safety of tACS treating MDD.Methods:This is an 8-week,double-blind,randomized,placebo-controlled study.Ninety-two drug-naive patients with MDD aged 18 to 65 years will receive 20 daily 40-min,77.5-Hz,15-mA sessions of active or sham tACS targeting the forehead and both mastoid areas on weekdays for 4 consecutive weeks(week 4),following a 4-week observation period(week 8).The primary outcome is the remission rate defined as the 17-item Hamilton depression rating scale(HDRS-17)score≤7 at week 8.Secondary outcomes are the rates of response at weeks 4 and 8 and rate of remission at week 4 based on HDRS-17,the proportion of participants having improvement in the clinical global impression-improvement,the change in HDRS-17 score(range,0-52,with higher scores indicating more depression)over the study,and variations of brain imaging and neurocognition from baseline to week 4.Safety will be assessed by vital signs at weeks 4 and 8,and adverse events will be collected during the entire study.Discussion:The tACS applied in this trial may have treatment effects on MDD with minimal side effects.Trial registration:Chinese Clinical Trial Registry,ChiCTR1800016479;http://www.chictr.org.cn/showproj.aspx?proj=22048.展开更多
Objective:We investigated changes in cortico–subcortical spatiotemporal dynamics to explore the treatment mechanisms oftranscranial alternating current stimulation(tACS)in patientswith Parkinson’s disease(PD).Method...Objective:We investigated changes in cortico–subcortical spatiotemporal dynamics to explore the treatment mechanisms oftranscranial alternating current stimulation(tACS)in patientswith Parkinson’s disease(PD).Methods:Resting-state functional magnetic resonance imaging(rs-fMRI)data were collected from 20 patients with PD and 20 normal controls(NC).Each patient with PD received successivemultidisciplinary intensive rehabilitation treatment and tACStreatment over a one-year interval.Individual functional brain network mapping and co-activation pattern(CAP)analysis were performed to characterize cortico–subcortical dynamics.Results:The same tACS electrode placement stimulated different proportions of functional brain networks across the participants.CAP analysis revealed that the visual network,attentional network,and default mode network co-activated with the thalamus,accumbens,and amygdala,respectively.The pattern characterized by thede-activation of the visual network and the activation of the thalamus showed a significantly low amplitude in the patients with PD than inNCs,and this amplitude increased after tACS treatment.Furthermore,the co-occurrence of cortico–subcortical CAPs was significantly higherin patients with PD than in NCs and decreased after tACS treatment.Conclusions:This study investigated cortico–subcortical spatiotemporaldynamics in patients with PD and further revealed the tACS treatmentmechanism.These findings contribute to understanding cortico–subcortical dynamics and exploring noninvasive neuromodulationtargets of cortico–subcortical circuits in brain diseases,such as PD,Alzheimer’s disease,and depression.展开更多
Non-invasive brain current stimulation（NIBS） is a promising and versatile tool for inducing neuroplasticity,protection and functional rehabilitation of damaged neuronal systems.It is technically simple,requires no s...Non-invasive brain current stimulation（NIBS） is a promising and versatile tool for inducing neuroplasticity,protection and functional rehabilitation of damaged neuronal systems.It is technically simple,requires no surgery,and has significant beneficial effects.However,there are various technical approaches for NIBS which influence neuronal networks in significantly different ways.Transcranial direct current stimulation（t DCS）,alternating current stimulation（ACS） and repetitive transcranial magnetic stimulation（r TMS） all have been applied to modulate brain activity in animal experiments under normal and pathological conditions.Also clinical trials have shown that t DCS,r TMS and ACS induce significant behavioural effects and can – depending on the parameters chosen – enhance or decrease brain excitability and influence performance and learning as well as rehabilitation and protective mechanisms.The diverse phaenomena and partially opposing effects of NIBS are not yet fully understood and mechanisms of action need to be explored further in order to select appropriate parameters for a given task,such as current type and strength,timing,distribution of current densities and electrode position.In this review,we will discuss the various parameters which need to be considered when designing a NIBS protocol and will put them into context with the envisaged applications in experimental neurobiology and medicine such as vision restoration,motor rehabilitation and cognitive enhancement.展开更多
Working memory is an executive memory process that includes encoding,maintenance,and retrieval.These processes can be modulated by transcranial alternating current stimulation(tACS)with sinusoidal waves.However,little...Working memory is an executive memory process that includes encoding,maintenance,and retrieval.These processes can be modulated by transcranial alternating current stimulation(tACS)with sinusoidal waves.However,little is known about the impact of the rate of current change on working memory.In this study,we aimed to investigate the effects of two types of tACS with different rates of current change on working memory performance and brain activity.We applied a randomized,single-blind design and divided 81 young participants who received triangular wave tACS,sinusoidal wave tACS,or sham stimulation into three groups.Participants performed n-back tasks,and electroencephalograms were recorded before,during,and after active or sham stimulation.Compared to the baseline,working memory performance(accuracy and response time)improved after stimulation under all stimulation conditions.According to drift-diffusion model analysis,triangular wave tACS significantly increased the efficiency of non-target information processing.In addition,compared with sham conditions,triangular wave tACS reduced alpha power oscillations in the occipital lobe throughout the encoding period,while sinusoidal wave tACS increased theta power in the central frontal region only during the later encoding period.The brain network connectivity results showed that triangular wave tACS improved the clustering coefficient,local efficiency,and node degree intensity in the early encoding stage,and these parameters were positively correlated with the non-target drift rate and decision starting point.Our findings on how tACS modulates working memory indicate that triangular wave tACS significantly enhances brain network connectivity during the early encoding stage,demonstrating an improvement in the efficiency of working memory processing.In contrast,sinusoidal wave tACS increased the theta power during the later encoding stage,suggesting its potential critical role in late-stage information processing.These findings provide valuable insights into the potential mechanisms by which tACS modulates working memory.展开更多
基金Supported by Shanghai Municipal Health Commission’s Special Clinical Research Project for the Hygiene Industry,No.20244Y0041Youth Initiation Fund of Naval Medical University,No.2023QN028 and No.2023QN030。
文摘BACKGROUND Working memory serves as a fundamental cognitive function that substantially impacts performance in various cognitive tasks.Extensive neurophysiological research has established that theta oscillations(4-8 Hz)play an essential role in supporting working memory operations.Theta-band transcranial alternating current stimulation(tACS)offers a potential mechanism for working memory enhancement through direct modulation of these fundamental neural oscillations.Nevertheless,current empirical evidence shows substantial variability in the observed effects of theta-tACS across studies.AIM To conduct a systematic review and meta-analysis evaluating the effects of thetatACS on working memory performance in healthy adults.METHODS A systematic literature search was performed on PubMed,EMBASE,and Web of Science up to March 10,2025.Effect sizes were computed using Hedges’g with 95%confidence intervals(CIs),with separate meta-analyses for all included studies and for distinct working memory paradigms[n-back and delayed matchto-sample(DMTS)tasks]to examine potential task-specific effects.Subgroup analyses and meta-regression were performed to evaluate the influence of key moderating variables.RESULTS The systematic review included 21 studies(67 effect sizes).Initial meta-analysis showed theta-tACS moderately improved working memory(Hedges’g=0.405,95%CI:0.212-0.598).However,this effect became nonsignificant after correcting for publication bias(trim-and-fill adjusted Hedges’g=0.082,95%CI:-0.052 to 0.217).Task-specific analyses revealed significant benefits in n-back tasks(Hedges’g=0.463,95%CI:0.193-0.733)but not in DMTS tasks(Hedges’g=0.257,95%CI:-0.186 to 0.553).Moderator analyses showed that performance in n-back tasks was influenced by stimulation frequency(P=0.001),concurrent status(P=0.014),task modality(P=0.005),and duration(P=0.013),whereas only the region of targeted stimulation(P=0.012)moderated DMTS tasks.CONCLUSION Theta-tACS enhances working memory in healthy adults,with effects modulated by the task type and protocol parameters,offering dual implications for cognitive enhancement and clinical interventions.
文摘For decades visual field defects were considered irreversible because it was thought that in the visual system the regeneration potential of the neuronal tissues is low.Nevertheless,there is always some potential for partial recovery of the visual field defect that can be achieved through induction of neuroplasticity.Neuroplasticity refers to the ability of the brain to change its own functional architecture by modulating synaptic efficacy.It is maintained throughout life and just as neurological rehabilitation can improve motor coordination,visual field defects in glaucoma,diabetic retinopathy or optic neuropathy can be improved by inducing neuroplasticity.In ophthalmology many new treatment paradigms have been tested that can induce neuroplastic changes,including non-invasive alternating current stimulation.Treatment with alternating current stimulation(e.g.,30 minutes,daily for 10 days using transorbital electrodes and^10 Hz)activates the entire retina and parts of the brain.Electroencephalography and functional magnetic resonance imaging studies revealed local activation of the visual cortex,global reorganization of functional brain networks,and enhanced blood flow,which together activate neurons and their networks.The future of low vision is optimistic because vision loss is indeed,partially reversible.
基金supported by grants from the National Key Research and Development Program of China(Nos.2021YFC2501400,2021YFC2501404).
文摘Transcranial alternating current stimulation(tACS)is a noninvasive neuromodulation technique that regulates brain function by applying sinusoidal alternating currents of specific frequencies to targeted brain regions through the scalp electrodes.[1]This guideline aims to evaluate and summarize the efficacy and safety of tACS in clinical applications.We conducted a structured literature search across major databases using the terms“tACS”or“transcranial alternating current stimulation”to identify all relevant literature up to June 2022.
基金This work is supported by the National Key R&D Program of China(No.2017YFC1310001)the National Natural Science Foundation of China(No.81771862)+2 种基金the Beijing Municipal Science and Technology Project(No.Z171100000117016)the Beijing Natural Science Foundation(No.KZ201710025017)the Beijing Hundred,Thousand,and Ten Thousand Talents Project(No.2017-CXYF-09).
文摘Background:Transcranial alternating current stimulation(tACS)offers a new approach for adult patients with major depressive disorder(MDD).The study is to evaluate the efficacy and safety of tACS treating MDD.Methods:This is an 8-week,double-blind,randomized,placebo-controlled study.Ninety-two drug-naive patients with MDD aged 18 to 65 years will receive 20 daily 40-min,77.5-Hz,15-mA sessions of active or sham tACS targeting the forehead and both mastoid areas on weekdays for 4 consecutive weeks(week 4),following a 4-week observation period(week 8).The primary outcome is the remission rate defined as the 17-item Hamilton depression rating scale(HDRS-17)score≤7 at week 8.Secondary outcomes are the rates of response at weeks 4 and 8 and rate of remission at week 4 based on HDRS-17,the proportion of participants having improvement in the clinical global impression-improvement,the change in HDRS-17 score(range,0-52,with higher scores indicating more depression)over the study,and variations of brain imaging and neurocognition from baseline to week 4.Safety will be assessed by vital signs at weeks 4 and 8,and adverse events will be collected during the entire study.Discussion:The tACS applied in this trial may have treatment effects on MDD with minimal side effects.Trial registration:Chinese Clinical Trial Registry,ChiCTR1800016479;http://www.chictr.org.cn/showproj.aspx?proj=22048.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.U20A20191,82071912,12104049,82202291)the Fundamental Research Funds for the Central Universities(Grant No.2021CX11011)the National Key Research and Development Program of China(Grant No.2020YFC2007305).
文摘Objective:We investigated changes in cortico–subcortical spatiotemporal dynamics to explore the treatment mechanisms oftranscranial alternating current stimulation(tACS)in patientswith Parkinson’s disease(PD).Methods:Resting-state functional magnetic resonance imaging(rs-fMRI)data were collected from 20 patients with PD and 20 normal controls(NC).Each patient with PD received successivemultidisciplinary intensive rehabilitation treatment and tACStreatment over a one-year interval.Individual functional brain network mapping and co-activation pattern(CAP)analysis were performed to characterize cortico–subcortical dynamics.Results:The same tACS electrode placement stimulated different proportions of functional brain networks across the participants.CAP analysis revealed that the visual network,attentional network,and default mode network co-activated with the thalamus,accumbens,and amygdala,respectively.The pattern characterized by thede-activation of the visual network and the activation of the thalamus showed a significantly low amplitude in the patients with PD than inNCs,and this amplitude increased after tACS treatment.Furthermore,the co-occurrence of cortico–subcortical CAPs was significantly higherin patients with PD than in NCs and decreased after tACS treatment.Conclusions:This study investigated cortico–subcortical spatiotemporaldynamics in patients with PD and further revealed the tACS treatmentmechanism.These findings contribute to understanding cortico–subcortical dynamics and exploring noninvasive neuromodulationtargets of cortico–subcortical circuits in brain diseases,such as PD,Alzheimer’s disease,and depression.
文摘Non-invasive brain current stimulation（NIBS） is a promising and versatile tool for inducing neuroplasticity,protection and functional rehabilitation of damaged neuronal systems.It is technically simple,requires no surgery,and has significant beneficial effects.However,there are various technical approaches for NIBS which influence neuronal networks in significantly different ways.Transcranial direct current stimulation（t DCS）,alternating current stimulation（ACS） and repetitive transcranial magnetic stimulation（r TMS） all have been applied to modulate brain activity in animal experiments under normal and pathological conditions.Also clinical trials have shown that t DCS,r TMS and ACS induce significant behavioural effects and can – depending on the parameters chosen – enhance or decrease brain excitability and influence performance and learning as well as rehabilitation and protective mechanisms.The diverse phaenomena and partially opposing effects of NIBS are not yet fully understood and mechanisms of action need to be explored further in order to select appropriate parameters for a given task,such as current type and strength,timing,distribution of current densities and electrode position.In this review,we will discuss the various parameters which need to be considered when designing a NIBS protocol and will put them into context with the envisaged applications in experimental neurobiology and medicine such as vision restoration,motor rehabilitation and cognitive enhancement.
基金supported by the Key-Area Research and Development Program of Guangdong Province(2023B0303030002)the Beijing Natural Science Foundation(IS23114,7242274)+4 种基金the China Postdoctoral Science Foundation(2023TQ0027 and 2024M754099)the STI 2030-Major Projects(2022ZD0208500)the National Natural Science Foundation of China(62336002,82071912,62406025,82202291,62373056,62306035)the Beijing Nova Program(20230484465)the Shenzhen Basic Research Program(JCYJ20241202124804007).
文摘Working memory is an executive memory process that includes encoding,maintenance,and retrieval.These processes can be modulated by transcranial alternating current stimulation(tACS)with sinusoidal waves.However,little is known about the impact of the rate of current change on working memory.In this study,we aimed to investigate the effects of two types of tACS with different rates of current change on working memory performance and brain activity.We applied a randomized,single-blind design and divided 81 young participants who received triangular wave tACS,sinusoidal wave tACS,or sham stimulation into three groups.Participants performed n-back tasks,and electroencephalograms were recorded before,during,and after active or sham stimulation.Compared to the baseline,working memory performance(accuracy and response time)improved after stimulation under all stimulation conditions.According to drift-diffusion model analysis,triangular wave tACS significantly increased the efficiency of non-target information processing.In addition,compared with sham conditions,triangular wave tACS reduced alpha power oscillations in the occipital lobe throughout the encoding period,while sinusoidal wave tACS increased theta power in the central frontal region only during the later encoding period.The brain network connectivity results showed that triangular wave tACS improved the clustering coefficient,local efficiency,and node degree intensity in the early encoding stage,and these parameters were positively correlated with the non-target drift rate and decision starting point.Our findings on how tACS modulates working memory indicate that triangular wave tACS significantly enhances brain network connectivity during the early encoding stage,demonstrating an improvement in the efficiency of working memory processing.In contrast,sinusoidal wave tACS increased the theta power during the later encoding stage,suggesting its potential critical role in late-stage information processing.These findings provide valuable insights into the potential mechanisms by which tACS modulates working memory.
