1
|
Balboa-Bandeira Y, Zubiaurre-Elorza L, García-Guerrero MA, Ibarretxe-Bilbao N, Ojeda N, Peña J. Enhancement of phonemic verbal fluency in multilingual young adults by transcranial random noise stimulation. Neuropsychologia 2024; 198:108882. [PMID: 38599569 DOI: 10.1016/j.neuropsychologia.2024.108882] [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: 07/19/2023] [Revised: 03/25/2024] [Accepted: 04/02/2024] [Indexed: 04/12/2024]
Abstract
Several studies have analyzed the effects of transcranial direct current stimulation on verbal fluency tasks in non-clinical populations. Nevertheless, the reported effects on verbal fluency are inconsistent. In addition, the effect of other techniques such as transcranial random noise stimulation (tRNS) on verbal fluency enhancement has yet to be studied in healthy multilingual populations. This study aims to explore the effects of tRNS on verbal fluency in healthy multilingual individuals. Fifty healthy multilingual (Spanish, English and Basque) adults were randomly assigned to a tRNS or sham group. Electrodes were placed on the left dorsolateral prefrontal cortex and left inferior frontal gyrus. All participants performed phonemic and semantic verbal fluency tasks before, during (online assessment) and immediately after (offline assessment) stimulation in three different languages. The results showed significantly better performance by participants who received tRNS in the phonemic verbal fluency tasks in Spanish (in the online and offline assessment) and English (in the offline assessment). No differences between conditions were found in Basque nor semantic verbal fluency. These findings suggests that tRNS on the left prefrontal cortex could help improve phonemic, yet not semantic, fluency in healthy multilingual adults.
Collapse
Affiliation(s)
| | - Leire Zubiaurre-Elorza
- Department of Psychology, Faculty of Health Sciences, University of Deusto, Bilbao, Spain
| | | | - Naroa Ibarretxe-Bilbao
- Department of Psychology, Faculty of Health Sciences, University of Deusto, Bilbao, Spain
| | - Natalia Ojeda
- Department of Psychology, Faculty of Health Sciences, University of Deusto, Bilbao, Spain
| | - Javier Peña
- Department of Psychology, Faculty of Health Sciences, University of Deusto, Bilbao, Spain.
| |
Collapse
|
2
|
Di Fuccio R, Lardone A, De Luca M, Ali L, Limone P, Marangolo P. Neurobiological Effects of Transcranial Direct Current Stimulation over the Inferior Frontal Gyrus: A Systematic Review on Cognitive Enhancement in Healthy and Neurological Adults. Biomedicines 2024; 12:1146. [PMID: 38927353 PMCID: PMC11200721 DOI: 10.3390/biomedicines12061146] [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: 04/16/2024] [Revised: 05/16/2024] [Accepted: 05/21/2024] [Indexed: 06/28/2024] Open
Abstract
The neurobiological effects of transcranial direct current stimulation (tDCS) have still not been unequivocally clarified. Some studies have suggested that the application of tDCS over the inferior frontal gyrus (IFG) enhances different aspects of cognition in healthy and neurological individuals, exerting neural changes over the target area and its neural surroundings. In this systematic review, randomized sham-controlled trials in healthy and neurological adults were selected through a database search to explore whether tDCS over the IFG combined with cognitive training modulates functional connectivity or neural changes. Twenty studies were finally included, among which twelve measured tDCS effects through functional magnetic resonance (fMRI), two through functional near-infrared spectroscopy (fNIRS), and six through electroencephalography (EEG). Due to the high heterogeneity observed across studies, data were qualitatively described and compared to assess reliability. Overall, studies that combined fMRI and tDCS showed widespread changes in functional connectivity at both local and distant brain regions. The findings also suggested that tDCS may also modulate electrophysiological changes underlying the targeted area. However, these outcomes were not always accompanied by corresponding significant behavioral results. This work raises the question concerning the general efficacy of tDCS, the implications of which extend to the steadily increasing tDCS literature.
Collapse
Affiliation(s)
- Raffaele Di Fuccio
- Department of Psychology and Educational Sciences, Telematic University of Pegaso, Piazza dei Santi Apostoli 49, 00187 Rome, Italy; (R.D.F.); (L.A.); (P.L.)
| | - Anna Lardone
- Department of Humanities Studies, University Federico II, Via Porta di Massa 1, 80133 Naples, Italy; (A.L.); (M.D.L.)
| | - Mariagiovanna De Luca
- Department of Humanities Studies, University Federico II, Via Porta di Massa 1, 80133 Naples, Italy; (A.L.); (M.D.L.)
| | - Leila Ali
- Department of Psychology and Educational Sciences, Telematic University of Pegaso, Piazza dei Santi Apostoli 49, 00187 Rome, Italy; (R.D.F.); (L.A.); (P.L.)
| | - Pierpaolo Limone
- Department of Psychology and Educational Sciences, Telematic University of Pegaso, Piazza dei Santi Apostoli 49, 00187 Rome, Italy; (R.D.F.); (L.A.); (P.L.)
| | - Paola Marangolo
- Department of Humanities Studies, University Federico II, Via Porta di Massa 1, 80133 Naples, Italy; (A.L.); (M.D.L.)
| |
Collapse
|
3
|
Figeys M, Loucks TM, Leung AWS, Kim ES. Transcranial direct current stimulation over the right dorsolateral prefrontal cortex increases oxyhemoglobin concentration and cognitive performance dependent on cognitive load. Behav Brain Res 2023; 443:114343. [PMID: 36787866 DOI: 10.1016/j.bbr.2023.114343] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 01/20/2023] [Accepted: 02/10/2023] [Indexed: 02/16/2023]
Abstract
Transcranial direct current stimulation (tDCS) has been explored as a potential method for cognitive enhancement. tDCS may induce a cascade of neurophysiological changes including alterations in cerebral oxygenation. However, the effects of tDCS on the cognitive-cerebral oxygenation interaction remains unclear. Further, oxygenation variability across individuals remains minimally controlled for. The purpose of this sham-controlled study was to test the effects of anodal tDCS over the right dorsolateral prefrontal cortex (DLPFC) on the interaction between working memory and cerebral oxygenation while controlling for individual oxygenation variability. Thirty-three adults received resting-state functional near-infrared spectroscopy (fNIRS) recordings over bilateral prefrontal cortices. Following this, working memory was tested using a Toulouse n-back task concurrently paired with fNIRS, with measurements taken before and after 20 min of anodal or sham tDCS at 1.5 mA. With individual oxygenation controlled for, anodal tDCS was found to increase the oxyhemoglobin concentration over the right DLPFC during the 2-back (q = .015) and 3-back (q = .008) conditions. Additionally, anodal tDCS was found to improve accuracy during the 3-back task by 13.4 % (p = .028) and decrease latency by 250 ms (p = .013). The increase in oxyhemoglobin was strongly correlated with increases in accuracy (p = .041) and decreases in latency during the 3-back span (p = .017). Taken together, anodal tDCS over the right DLPFC was found to regionally increase oxyhemoglobin concentrations and improve working memory performance in higher cognitive load conditions.
Collapse
Affiliation(s)
- Mathieu Figeys
- Faculty of Rehabilitation Medicine, University of Alberta, Edmonton T6G 2G4, Alberta, Canada.
| | - Torrey M Loucks
- Department of Communication Sciences and Disorders, School of Applied Health Sciences, Brooks Rehabilitation College of Healthcare Sciences, Jacksonville University - Palm Coast Campus, FL, United States
| | - Ada W S Leung
- Faculty of Rehabilitation Medicine, University of Alberta, Edmonton T6G 2G4, Alberta, Canada; Department of Occupational Therapy, University of Alberta, Edmonton T6G 2G4, Alberta, Canada
| | - Esther S Kim
- Faculty of Rehabilitation Medicine, University of Alberta, Edmonton T6G 2G4, Alberta, Canada; Department of Communication Sciences and Disorders, University of Alberta, Edmonton T6G 2G4, Alberta, Canada
| |
Collapse
|
4
|
Guo Z, Gong Y, Lu H, Qiu R, Wang X, Zhu X, You X. Multitarget high-definition transcranial direct current stimulation improves response inhibition more than single-target high-definition transcranial direct current stimulation in healthy participants. Front Neurosci 2022; 16:905247. [PMID: 35968393 PMCID: PMC9372262 DOI: 10.3389/fnins.2022.905247] [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: 03/26/2022] [Accepted: 07/11/2022] [Indexed: 11/21/2022] Open
Abstract
Prior studies have focused on single-target anodal transcranial direct current stimulation (tDCS) over the right inferior frontal gyrus (rIFG) or pre-supplementary motor area (pre-SMA) to improve response inhibition in healthy individuals. However, the results are contradictory and the effect of multitarget anodal stimulation over both brain regions has never been investigated. The present study aimed to investigate the behavioral and neurophysiological effects of different forms of anodal high-definition tDCS (HD-tDCS) on improving response inhibition, including HD-tDCS over the rIFG or pre-SMA and multitarget HD-tDCS over both areas. Ninety-two healthy participants were randomly assigned to receive single-session (20 min) anodal HD-tDCS over rIFG + pre-SMA, rIFG, pre-SMA, or sham stimulation. Before and immediately after tDCS intervention, participants completed a stop-signal task (SST) and a go/nogo task (GNG). Their cortical activity was recorded using functional near-infrared spectroscopy (fNIRS) during the go/nogo task. The results showed multitarget stimulation produced a significant reduction in stop-signal reaction time (SSRT) relative to baseline. The pre-to-post SSRT change was not significant for rIFG, pre-SMA, or sham stimulation. Further analyses revealed multitarget HD-tDCS significantly decreased SSRT in both the high-performance and low-performance subgroups compared with the rIFG condition which decreased SSRT only in the low-performance subgroup. Only the multitarget condition significantly improved neural efficiency as indexed by lower △oxy-Hb after stimulation. In conclusion, the present study provides important preliminary evidence that multitarget HD-tDCS is a promising avenue to improve stimulation efficacy, establishing a more effective montage to enhance response inhibition relative to the commonly used single-target stimulation.
Collapse
Affiliation(s)
- Zhihua Guo
- Department of Military Medical Psychology, Air Force Medical University, Xi’an, China
| | - Yue Gong
- School of Psychology, Shaanxi Normal University, Xi’an, China
| | - Hongliang Lu
- Department of Military Medical Psychology, Air Force Medical University, Xi’an, China
| | - Rui Qiu
- Department of Military Medical Psychology, Air Force Medical University, Xi’an, China
| | - Xinlu Wang
- Department of Military Medical Psychology, Air Force Medical University, Xi’an, China
| | - Xia Zhu
- Department of Military Medical Psychology, Air Force Medical University, Xi’an, China
- *Correspondence: Xia Zhu,
| | - Xuqun You
- School of Psychology, Shaanxi Normal University, Xi’an, China
- Xuqun You,
| |
Collapse
|
5
|
Hong KS, Khan MNA, Ghafoor U. Non-invasive transcranial electrical brain stimulation guided by functional near-infrared spectroscopy for targeted neuromodulation: A review. J Neural Eng 2022; 19. [PMID: 35905708 DOI: 10.1088/1741-2552/ac857d] [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: 02/16/2021] [Accepted: 07/29/2022] [Indexed: 11/12/2022]
Abstract
One of the primary goals in cognitive neuroscience is to understand the neural mechanisms on which cognition is based. Researchers are trying to find how cognitive mechanisms are related to oscillations generated due to brain activity. The research focused on this topic has been considerably aided by developing non-invasive brain stimulation techniques. The dynamics of brain networks and the resultant behavior can be affected by non-invasive brain stimulation techniques, which make their use a focus of interest in many experiments and clinical fields. One essential non-invasive brain stimulation technique is transcranial electrical stimulation (tES), subdivided into transcranial direct and alternating current stimulation. tES has recently become more well-known because of the effective results achieved in treating chronic conditions. In addition, there has been exceptional progress in the interpretation and feasibility of tES techniques. Summarizing the beneficial effects of tES, this article provides an updated depiction of what has been accomplished to date, brief history, and the open questions that need to be addressed in the future. An essential issue in the field of tES is stimulation duration. This review briefly covers the stimulation durations that have been utilized in the field while monitoring the brain using functional-near infrared spectroscopy-based brain imaging.
Collapse
Affiliation(s)
- Keum-Shik Hong
- Department of Cogno-mechatronics Engineering, Pusan National University, 2 Busandaehak-ro, Geumgeong-gu, Busan, Busan, 609735, Korea (the Republic of)
| | - M N Afzal Khan
- Pusan National University, Department of Mechanical Engineering, Busan, 46241, Korea (the Republic of)
| | - Usman Ghafoor
- School of Mechanical Engineering, Pusan National University College of Engineering, room 204, Busan, 46241, Korea (the Republic of)
| |
Collapse
|
6
|
Gnedykh D, Tsvetova D, Mkrtychian N, Blagovechtchenski E, Kostromina S, Shtyrov Y. Broca’s area involvement in abstract and concrete word acquisition: tDCS evidence. Neurobiol Learn Mem 2022; 192:107622. [DOI: 10.1016/j.nlm.2022.107622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 02/01/2022] [Accepted: 04/19/2022] [Indexed: 10/18/2022]
|
7
|
Yang C, Zhang T, Huang K, Xiong M, Liu H, Wang P, Zhang Y. Increased both cortical activation and functional connectivity after transcranial direct current stimulation in patients with post-stroke: A functional near-infrared spectroscopy study. Front Psychiatry 2022; 13:1046849. [PMID: 36569623 PMCID: PMC9784914 DOI: 10.3389/fpsyt.2022.1046849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Accepted: 11/14/2022] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Previous studies have shown that cognitive impairment is common after stroke. Transcranial direct current stimulation (tDCS) is a promising tool for rehabilitating cognitive impairment. This study aimed to investigate the effects of tDCS on the rehabilitation of cognitive impairment in patients with stroke. METHODS Twenty-two mild-moderate post-stroke patients with cognitive impairments were treated with 14 tDCS sessions. A total of 14 healthy individuals were included in the control group. Cognitive function was assessed using the Mini-Mental State Examination (MMSE) and the Montreal Cognitive Assessment (MoCA). Cortical activation was assessed using functional near-infrared spectroscopy (fNIRS) during the verbal fluency task (VFT). RESULTS The cognitive function of patients with stroke, as assessed by the MMSE and MoCA scores, was lower than that of healthy individuals but improved after tDCS. The cortical activation of patients with stroke was lower than that of healthy individuals in the left superior temporal cortex (lSTC), right superior temporal cortex (rSTC), right dorsolateral prefrontal cortex (rDLPFC), right ventrolateral prefrontal cortex (rVLPFC), and left ventrolateral prefrontal cortex (lVLPFC) cortical regions. Cortical activation increased in the lSTC cortex after tDCS. The functional connectivity (FC) between the cerebral hemispheres of patients with stroke was lower than that of healthy individuals but increased after tDCS. CONCLUSION The cognitive and brain functions of patients with mild-to-moderate stroke were damaged but recovered to a degree after tDCS. Increased cortical activation and increased FC between the bilateral cerebral hemispheres measured by fNIRS are promising biomarkers to assess the effectiveness of tDCS in stroke.
Collapse
Affiliation(s)
- Caihong Yang
- Department of Rehabilitation Medicine, The Seventh Affiliated Hospital, Sun Yat-sen University, Shenzhen, Guangdong, China.,School of Psychology, Central China Normal University, Wuhan, Hubei, China
| | - Tingyu Zhang
- Department of Rehabilitation Medicine, The Seventh Affiliated Hospital, Sun Yat-sen University, Shenzhen, Guangdong, China
| | - Kaiqi Huang
- The Seventh Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Menghui Xiong
- Brain Cognition and Brain Disease Institute (BCBDI), Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Huiyu Liu
- Department of Rehabilitation Medicine, Yue Bei People's Hospital, Shaoguan, Guangdong, China
| | - Pu Wang
- Department of Rehabilitation Medicine, The Seventh Affiliated Hospital, Sun Yat-sen University, Shenzhen, Guangdong, China.,Department of Rehabilitation Medicine, Tianyang District People's Hospital, Baise, Guangxi, China
| | - Yan Zhang
- School of Educational Science, Huazhong University of Science and Technology, Wuhan, Hubei, China
| |
Collapse
|
8
|
Chang F, Li H, Li N, Zhang S, Liu C, Zhang Q, Cai W. Functional near-infrared spectroscopy as a potential objective evaluation technique in neurocognitive disorders after traumatic brain injury. Front Psychiatry 2022; 13:903756. [PMID: 35935423 PMCID: PMC9352882 DOI: 10.3389/fpsyt.2022.903756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Accepted: 06/27/2022] [Indexed: 11/13/2022] Open
Abstract
Most patients with neurocognitive disorders after traumatic brain injury (TBI) show executive dysfunction, in which the pre-frontal cortex (PFC) plays an important role. However, less objective evaluation technique could be used to assess the executive dysfunction in these patients. Functional near-infrared spectroscopy (fNIRS), which is a non-invasive technique, has been widely used in the study of psychiatric disorders, cognitive dysfunction, etc. The present study aimed to explore whether fNIRS could be a technique to assess the damage degree of executive function in patients with neurocognitive disorders after TBI by using the Stroop and N-back tasks in PFC areas. We enrolled 37 patients with neurocognitive disorders after TBI and 60 healthy controls. A 22-channel fNIRS device was used to record HbO during Stroop, 1-back and 2-back tasks. The results showed that patients made significantly more errors and had longer response times than healthy controls. There were statistically significant differences in HbO level variation in bilateral frontopolar, bilateral inferior frontal gyrus and left middle temporal gyrus during Stroop color word consistency tasks and in left frontopolar during Stroop color word inconsistency tasks. During 2-back tasks, there were also statistically significant differences in HbO level variation in bilateral frontopolar, bilateral inferior frontal gyrus, bilateral dorsolateral pre-frontal cortex. According to brain activation maps, the patients exhibited lower but more widespread activation during the 2-back and Stroop color word consistency tasks. The fNIRS could identify executive dysfunction in patients with neurocognitive disorders after TBI by detecting HbO levels, which suggested that fNIRS could be a potential objective evaluation technique in neurocognitive disorders after TBI.
Collapse
Affiliation(s)
- Fan Chang
- Shanghai Key Laboratory of Forensic Medicine, Key Lab of Forensic Science, Ministry of Justice, Shanghai Forensic Service Platform, Academy of Forensic Science, Shanghai, China.,Sichuan Provincial Center for Mental Health, Sichuan Academy of Medical Science, Sichuan Provincial People's Hospital, Chengdu, China
| | - Haozhe Li
- Shanghai Key Laboratory of Forensic Medicine, Key Lab of Forensic Science, Ministry of Justice, Shanghai Forensic Service Platform, Academy of Forensic Science, Shanghai, China
| | - Ningning Li
- Hongkou Mental Health Center, Shanghai, China
| | - Shengyu Zhang
- Shanghai Key Laboratory of Forensic Medicine, Key Lab of Forensic Science, Ministry of Justice, Shanghai Forensic Service Platform, Academy of Forensic Science, Shanghai, China
| | - Chao Liu
- Shanghai Key Laboratory of Forensic Medicine, Key Lab of Forensic Science, Ministry of Justice, Shanghai Forensic Service Platform, Academy of Forensic Science, Shanghai, China
| | - Qinting Zhang
- Shanghai Key Laboratory of Forensic Medicine, Key Lab of Forensic Science, Ministry of Justice, Shanghai Forensic Service Platform, Academy of Forensic Science, Shanghai, China
| | - Weixiong Cai
- Shanghai Key Laboratory of Forensic Medicine, Key Lab of Forensic Science, Ministry of Justice, Shanghai Forensic Service Platform, Academy of Forensic Science, Shanghai, China
| |
Collapse
|
9
|
Ghafoor U, Yang D, Hong KS. Neuromodulatory effects of HD-tACS/tDCS on the prefrontal cortex: A resting-state fNIRS-EEG study. IEEE J Biomed Health Inform 2021; 26:2192-2203. [PMID: 34757916 DOI: 10.1109/jbhi.2021.3127080] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Transcranial direct and alternating current stimulation (tDCS and tACS, respectively) can modulate human brain dynamics and cognition. However, these modalities have not been compared using multiple imaging techniques concurrently. In this study, 15 participants participated in an experiment involving two sessions with a gap of 10 d. In the first and second sessions, tACS and tDCS were administered to the participants. The anode for tDCS was positioned at point FpZ, and four cathodes were positioned over the left and right prefrontal cortices (PFCs) to target the frontal regions simultaneously. tDCS was administered with 1 mA current. tACS was supplied with a current of 1 mA (zero-to-peak value) at 10 Hz frequency. Stimulation was applied concomitantly with functional near-infrared spectroscopy and electroencephalography acquisitions in the resting-state. The statistical test showed significant alteration (p < 0.001) in the mean hemodynamic responses during and after tDCS and tACS periods. Between-group comparison revealed a significantly less (p < 0.001) change in the mean hemodynamic response caused by tACS compared with tDCS. As hypothesized, we successfully increased the hemodynamics in both left and right PFCs using tDCS and tACS. Moreover, a significant increase in alpha-band power (p < 0.01) and low beta band power (p < 0.05) due to tACS was observed after the stimulation period. Although tDCS is not frequency-specific, it increased but not significantly (p > 0.05) the powers of most bands including delta, theta, alpha, low beta, high beta, and gamma. These findings suggest that both hemispheres can be targeted and that both tACS and tDCS are equally effective in high-definition configurations, which may be of clinical relevance.
Collapse
|
10
|
Yaqub MA, Hong KS, Zafar A, Kim CS. Control of Transcranial Direct Current Stimulation Duration by Assessing Functional Connectivity of Near-Infrared Spectroscopy Signals. Int J Neural Syst 2021; 32:2150050. [PMID: 34609264 DOI: 10.1142/s0129065721500507] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Transcranial direct current stimulation (tDCS) has been shown to create neuroplasticity in healthy and diseased populations. The control of stimulation duration by providing real-time brain state feedback using neuroimaging is a topic of great interest. This study presents the feasibility of a closed-loop modulation for the targeted functional network in the prefrontal cortex. We hypothesize that we cannot improve the brain state further after reaching a specific state during a stimulation therapy session. A high-definition tDCS of 1[Formula: see text]mA arranged in a ring configuration was applied at the targeted right prefrontal cortex of 15 healthy male subjects for 10[Formula: see text]min. Functional near-infrared spectroscopy was used to monitor hemoglobin chromophores during the stimulation period continuously. The correlation matrices obtained from filtered oxyhemoglobin were binarized to form subnetworks of short- and long-range connections. The connectivity in all subnetworks was analyzed individually using a new quantification measure of connectivity percentage based on the correlation matrix. The short-range network in the stimulated hemisphere showed increased connectivity in the initial stimulation phase. However, the increase in connection density reduced significantly after 6[Formula: see text]min of stimulation. The short-range network of the left hemisphere and the long-range network gradually increased throughout the stimulation period. The connectivity percentage measure showed a similar response with network theory parameters. The connectivity percentage and network theory metrics represent the brain state during the stimulation therapy. The results from the network theory metrics, including degree centrality, efficiency, and connection density, support our hypothesis and provide a guideline for feedback on the brain state. The proposed neuro-feedback scheme is feasible to control the stimulation duration to avoid overdosage.
Collapse
Affiliation(s)
- M Atif Yaqub
- ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
| | - Keum-Shik Hong
- School of Mechanical Engineering, Pusan National University, 2 Busandaehak-ro, Geumjeong-gu, Busan 46241, Korea
| | - Amad Zafar
- Department of Electrical Engineering, University of Lahore, Sihala Zone V, Islamabad, Pakistan
| | - Chang-Seok Kim
- Department of Cogno-Mechatronics Engineering, Pusan National University, 2 Busandaehak-ro, Geumjeong-gu, Busan 46241, Korea
| |
Collapse
|
11
|
Modulation of Working Memory and Resting-State fMRI by tDCS of the Right Frontoparietal Network. Neural Plast 2021; 2021:5594305. [PMID: 34349797 PMCID: PMC8328716 DOI: 10.1155/2021/5594305] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 06/25/2021] [Accepted: 07/09/2021] [Indexed: 11/20/2022] Open
Abstract
Many cognitive functions, including working memory, are processed within large-scale brain networks. We targeted the right frontoparietal network (FPN) with one session of transcranial direct current stimulation (tDCS) in an attempt to modulate the cognitive speed of a visual working memory task (WMT) in 27 young healthy subjects using a double-blind crossover design. We further explored the neural underpinnings of induced changes by performing resting-state fMRI prior to and immediately after each stimulation session with the main focus on the interaction between a task-positive FPN and a task-negative default mode network (DMN). Twenty minutes of 2 mA anodal tDCS was superior to sham stimulation in terms of cognitive speed manipulation of a subtask with processing of objects and tools in unconventional views (i.e., the higher cognitive load subtask of the offline WMT). This result was linked to the magnitude of resting-state functional connectivity decreases between the stimulated FPN seed and DMN seeds. We provide the first evidence for the action reappraisal mechanism of object and tool processing. Modulation of cognitive speed of the task by tDCS was reflected by FPN-DMN cross-talk changes.
Collapse
|
12
|
Figeys M, Zeeman M, Kim ES. Effects of Transcranial Direct Current Stimulation (tDCS) on Cognitive Performance and Cerebral Oxygen Hemodynamics: A Systematic Review. Front Hum Neurosci 2021; 15:623315. [PMID: 33897392 PMCID: PMC8058208 DOI: 10.3389/fnhum.2021.623315] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 03/11/2021] [Indexed: 11/24/2022] Open
Abstract
Background: There is increasing evidence to support the efficacy of transcranial direct current stimulation (tDCS) applications in cognitive augmentation and rehabilitation. Neuromodulation achieved with tDCS may further regulate regional cerebral perfusion affiliated through the neurovascular unit; however, components of cerebral perfusion decrease across aging. A novel neuroimaging approach, functional near-infrared spectroscopy (fNIRS), can aid in quantifying these regional perfusional changes. To date, the interaction of the effects of tDCS on cognitive performance across the lifespan and obtained fNIRS hemodynamic responses remain unknown. Objective: This review aims to examine the effects of tDCS on cognitive performance and fNIRS hemodynamic responses within the context of cognitive aging. Methods: Six databases were searched for studies. Quality appraisal and data extraction were conducted by two independent reviewers. Meta-analysis was carried out to determine overall and subgroup effect sizes. Results: Eight studies met inclusion criteria. The overall effect size demonstrates that tDCS can alter cognitive performance and fNIRS signals, with aging being a potential intermediary in tDCS efficacy. Conclusion: From the studies included, the effects of tDCS on cognitive performance and fNIRS metrics are most prominent in young healthy adults and appear to become less robust with increasing age. Given the small number of studies included in this review further investigation is recommended.
Collapse
Affiliation(s)
- Mathieu Figeys
- Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, AB, Canada
| | - Michael Zeeman
- Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Esther Sung Kim
- Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, AB, Canada.,Department of Communication Sciences and Disorders, University of Alberta, Edmonton, AB, Canada
| |
Collapse
|
13
|
Lema A, Carvalho S, Fregni F, Gonçalves ÓF, Leite J. The effects of direct current stimulation and random noise stimulation on attention networks. Sci Rep 2021; 11:6201. [PMID: 33737661 PMCID: PMC7973424 DOI: 10.1038/s41598-021-85749-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 02/25/2021] [Indexed: 01/31/2023] Open
Abstract
Attention is a complex cognitive process that selects specific stimuli for further processing. Previous research suggested the existence of three attentional networks: alerting, orienting and executive. However, one important topic is how to enhance the efficiency of attentional networks. In this context, understanding how this system behaves under two different modulatory conditions, namely transcranial direct current stimulation (tDCS) and transcranial Random Noise Stimulation (tRNS), will provide important insights towards the understanding of the attention network system. Twenty-seven healthy students took part on a randomized single-blinded crossover study, testing the effects that involved three modalities of unilateral stimulation (tRNS, anodal tDCS, and sham) over the DLPFC, during the performance of the attention network test (ANT) in three different conditions: standard, speed and accuracy. Results showed that tRNS was able to increase attention during more complex situations, namely by increasing alerting and decreasing conflict effect in the executive network. Under the Speed condition, tRNS increased efficiency of the alerting network, as well as under the more demanding conflict network, tRNS overall increased the performance when comparing to sham. No statistical significant effects of tDCS were observed. These results are compatible with the attention requiring the synchronization of pre-existing networks, rather the reinforcement or creation of new pathways.
Collapse
Affiliation(s)
- Alberto Lema
- Psychological Neuroscience Laboratory, CIPsi, School of Psychology, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal
| | - Sandra Carvalho
- Psychological Neuroscience Laboratory, CIPsi, School of Psychology, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal
- Department of Education and Psychology, University of Aveiro, Campus Universitário de Santiago, Aveiro, Portugal
| | - Felipe Fregni
- Spaulding Neuromodulation Center, Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital & Massachusetts General Hospital, Harvard Medical School, Boston, USA
| | - Óscar F Gonçalves
- Proaction Laboratory, Faculty of Psychology and Educational Sciences, University of Coimbra, Coimbra, Portugal
| | - Jorge Leite
- I2P-Portucalense Institute for Psychology, Portucalense University, Porto, Portugal.
| |
Collapse
|
14
|
Noninvasive brain stimulation to lateral prefrontal cortex alters the novelty of creative idea generation. COGNITIVE AFFECTIVE & BEHAVIORAL NEUROSCIENCE 2021; 21:311-326. [PMID: 33624232 DOI: 10.3758/s13415-021-00869-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 01/16/2021] [Indexed: 11/08/2022]
Abstract
Theories of the processes involved in creative cognition posit that cognitive control has a negative effect on creative idea generation but a positive effect on creative idea evaluation. Brain stimulation research has started to examine empirically the effects of cognitive control, with several reports of decreased cognitive control facilitating creative ideation. Such studies have shown how decreased cognitive control mechanisms facilitate creative idea generation, potentially by allowing participants access to less inhibited weaker-related associations, thereby increasing novelty. In the current study, we advance this line of work by investigating how cognitive control affects creative thinking, potentially inhibiting or facilitating novel idea generation based on task demands. Participants read sentences with the final word missing and were instructed to complete the sentence with an uncommon (but appropriate) ending. Participants performed this task while undergoing either anodal (excitatory), cathodal (inhibitory), or sham (control) transcranial direct current stimulation over their left prefrontal cortex. These responses were then rated for their novelty and appropriateness by an independent sample of raters. We found that anodal stimulation increased the appropriateness and decreased the novelty of participants' responses. Contrary to previous studies, we did not find that cathodal stimulation increased the novelty of participants' responses, which may be due to the nature of our task. Overall, we demonstrate how cognitive control mechanisms may inhibit novel idea generation.
Collapse
|
15
|
Patel R, Dawidziuk A, Darzi A, Singh H, Leff DR. Systematic review of combined functional near-infrared spectroscopy and transcranial direct-current stimulation studies. NEUROPHOTONICS 2020; 7:020901. [PMID: 32607389 PMCID: PMC7315225 DOI: 10.1117/1.nph.7.2.020901] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 06/15/2020] [Indexed: 05/05/2023]
Abstract
Significance: Combining transcranial direct-current stimulation (tDCS) with functional near-infrared spectroscopy (fNIRS) is a recent approach to exploring brain activation evoked by neurostimulation. Aim: To critically evaluate studies combining tDCS and fNIRS and provide a consolidated overview of cortical hemodynamic responses to neurostimulation. Approach: Key terms were searched in three databases (MEDLINE, EMBASE, and PsycINFO) with cross-referencing and works from Google Scholar also evaluated. All studies reporting on fNIRS-derived hemoglobin changes evoked by tDCS were included. Results: Literature searches revealed 474 articles, of which 28 were included for final review (22 in healthy individuals: 9 involving rest and 13 with tasks; 6 in the clinical setting). At rest, an overall increase in cortical activation was observed in fNIRS responses at the site of stimulation, with evidence suggesting nonstimulated brain regions are also similarly affected. Conversely, during tasks, reduced cortical activation was observed during online stimulation. Offline and poststimulation effects were less consistent, as is the impact on clinical populations and their symptom correlation. Conclusion: This review explores the methodological frameworks for fNIRS-tDCS evaluations and summarizes hemodynamic responses associated with tDCS in all populations. Our findings provide further evidence of the impact of tDCS on neuronal activation within functionally connected networks.
Collapse
Affiliation(s)
- Ronak Patel
- St. Mary’s Hospital Campus, Imperial College London, Department of Surgery and Cancer, London, United Kingdom
- Address all correspondence to Ronak Patel, E-mail:
| | - Aleksander Dawidziuk
- St. Mary’s Hospital Campus, Imperial College London, Department of Surgery and Cancer, London, United Kingdom
| | - Ara Darzi
- St. Mary’s Hospital Campus, Imperial College London, Department of Surgery and Cancer, London, United Kingdom
| | - Harsimrat Singh
- St. Mary’s Hospital Campus, Imperial College London, Department of Surgery and Cancer, London, United Kingdom
| | - Daniel Richard Leff
- St. Mary’s Hospital Campus, Imperial College London, Department of Surgery and Cancer, London, United Kingdom
| |
Collapse
|
16
|
Yang Y, Chen T, Shao M, Yan S, Yue GH, Jiang C. Effects of Tai Chi Chuan on Inhibitory Control in Elderly Women: An fNIRS Study. Front Hum Neurosci 2020; 13:476. [PMID: 32038205 PMCID: PMC6988574 DOI: 10.3389/fnhum.2019.00476] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2019] [Accepted: 12/31/2019] [Indexed: 01/04/2023] Open
Abstract
Background Inhibitory control is a sub-ability of executive function and plays an important role in the entire cognitive process. However, declines in inhibitory control during aging significantly impair the quality of life of elderly people. Investigating methods to delay the decline of inhibitory control has become a focal point in current research. Tai Chi Chuan (TCC) is one effective method used to delay cognitive declines in older adults. However, the specific effects of TCC on inhibitory control and the mechanisms through which TCC may improve cognition in older adults have not been comprehensively investigated. Objective The study explores possible neurological mechanisms related to the effects of TCC interventions on inhibitory control in older people using a functional near-infrared spectroscopy (fNIRS) technique and reaction times (RTs). Methods A total of 26 healthy, elderly people who had not received TCC training completed all study procedures. The subjects were randomized to either the TCC group or the control group. Subjects in the TCC group were taught TCC by a certified instructor and trained for 8 weeks. The control group continued to perform general daily activities. The Flanker task was administered to every participant to evaluate inhibitory control pre- and post-intervention. While participants were performing the Flanker task, fNIRS data were collected. Results Post-intervention, significant differences for incongruent flankers were found only for the TCC intervention group. Faster RTs were observed for the incongruent flankers in the TCC group than in the control group (p < 0.05). Analysis of the fNIRS data revealed an increase in oxy-Hb in the prefrontal cortex during the incongruent flankers after the TCC exercise intervention. Conclusion The TCC intervention significantly improved inhibitory control in older adults, suggesting that TCC is an effective, suitable exercise for improving executive function and neurological health in elderly people. Clinical Trial Registration Chinese Clinical Trial Register, ChiCTR1900028457.
Collapse
Affiliation(s)
- Yuan Yang
- Beijing Key Laboratory of Physical Fitness Evaluation and Technical Analysis, Capital University of Physical Education and Sports, Beijing, China.,The Center of Neuroscience and Sports, Capital University of Physical Education and Sports, Beijing, China
| | - Tingting Chen
- School of Education, Beijing Dance Academy, Beijing, China
| | - Mingming Shao
- Beijing Key Laboratory of Physical Fitness Evaluation and Technical Analysis, Capital University of Physical Education and Sports, Beijing, China.,The Center of Neuroscience and Sports, Capital University of Physical Education and Sports, Beijing, China
| | - Shoufu Yan
- School of Kinesiology and Health, Capital University of Physical Education and Sports, Beijing, China
| | - Guang H Yue
- Center for Mobility and Rehabilitation Engineering, Kessler Foundation, West Orange, NJ, United States.,Rutgers New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, United States
| | - Changhao Jiang
- Beijing Key Laboratory of Physical Fitness Evaluation and Technical Analysis, Capital University of Physical Education and Sports, Beijing, China.,The Center of Neuroscience and Sports, Capital University of Physical Education and Sports, Beijing, China.,School of Kinesiology and Health, Capital University of Physical Education and Sports, Beijing, China
| |
Collapse
|
17
|
Effects of parietal exogenous oscillatory field potentials on subjectively perceived memory confidence. Neurobiol Learn Mem 2019; 168:107140. [PMID: 31843652 DOI: 10.1016/j.nlm.2019.107140] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 11/11/2019] [Accepted: 12/12/2019] [Indexed: 11/20/2022]
Abstract
Previous research suggests involvement of parietal theta (3-7 Hz) power in subjectively perceived memory confidence during retrieval. To obtain further insights into the role of parietal theta activity during retrieval in processes associated with performance and confidence, fifty-four healthy volunteers performed a recognition memory task in a within-subject sham controlled transcranial alternating current stimulation (tACS) study. Participants encoded a subset of words at specific on-screen locations. During the retrieval phase accuracy and subjectively perceived confidence on item and source memory were evaluated while administering exogenous alternating field potentials. Results showed that 3.5 Hz tACS decreased subjectively perceived memory confidence as compared to sham and 8 Hz tACS. No tACS effects were found on accuracy regarding item and source memory. Our findings suggest that theta activity in the parietal cortex is implicated in subjectively perceived confidence in word recognition.
Collapse
|
18
|
Di Rosa E, Brigadoi S, Cutini S, Tarantino V, Dell'Acqua R, Mapelli D, Braver TS, Vallesi A. Reward motivation and neurostimulation interact to improve working memory performance in healthy older adults: A simultaneous tDCS-fNIRS study. Neuroimage 2019; 202:116062. [PMID: 31369810 DOI: 10.1016/j.neuroimage.2019.116062] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 07/25/2019] [Accepted: 07/27/2019] [Indexed: 01/12/2023] Open
Abstract
Several studies have evaluated the effect of anodal transcranial direct current stimulation (tDCS) over the prefrontal cortex (PFC) for the enhancement of working memory (WM) performance in healthy older adults. However, the mixed results obtained so far suggest the need for concurrent brain imaging, in order to more directly examine tDCS effects. The present study adopted a continuous multimodal approach utilizing functional near-infrared spectroscopy (fNIRS) to examine the interactive effects of tDCS combined with manipulations of reward motivation. Twenty-one older adults (mean age = 69.7 years; SD = 5.05) performed an experimental visuo-spatial WM task before, during and after the delivery of 1.5 mA anodal tDCS/sham over the left prefrontal cortex (PFC). During stimulation, participants received performance-contingent reward for every fast and correct response during the WM task. In both sessions, hemodynamic activity of the bilateral frontal, motor and parietal areas was recorded across the entire duration of the WM task. Cognitive functions and reward sensitivity were also assessed with standard measures. Results demonstrated a significant impact of tDCS on both WM performance and hemodynamic activity. Specifically, faster responses in the WM task were observed both during and after anodal tDCS, while no differences were found under sham control conditions. However, these effects emerged only when taking into account individual visuo-spatial WM capacity. Additionally, during and after the anodal tDCS, increased hemodynamic activity relative to sham was observed in the bilateral PFC, while no effects of tDCS were detected in the motor and parietal areas. These results provide the first evidence of tDCS-dependent functional changes in PFC activity in healthy older adults during the execution of a WM task. Moreover, they highlight the utility of combining reward motivation with prefrontal anodal tDCS, as a potential strategy to improve WM efficiency in low performing healthy older adults.
Collapse
Affiliation(s)
- Elisa Di Rosa
- Department of Neuroscience & Padova Neuroscience Center, University of Padova, Padova, Italy; Department of Psychological & Brain Sciences, Washington University in St. Louis, St. Louis, USA.
| | - Sabrina Brigadoi
- Department of Developmental Psychology, University of Padova, Padova, Italy; Department of Information Engineering, University of Padova, Padova, Italy
| | - Simone Cutini
- Department of Developmental Psychology, University of Padova, Padova, Italy; Padova Neuroscience Center, University of Padova, Padova, Italy
| | - Vincenza Tarantino
- Department of Neuroscience & Padova Neuroscience Center, University of Padova, Padova, Italy; Department of Psychology, Educational Science and Human Movement, University of Palermo, Palermo, Italy
| | - Roberto Dell'Acqua
- Department of Developmental Psychology, University of Padova, Padova, Italy; Padova Neuroscience Center, University of Padova, Padova, Italy
| | - Daniela Mapelli
- Department of General Psychology, University of Padova, Padova, Italy
| | - Todd S Braver
- Department of Psychological & Brain Sciences, Washington University in St. Louis, St. Louis, USA
| | - Antonino Vallesi
- Department of Neuroscience & Padova Neuroscience Center, University of Padova, Padova, Italy; Brain Imaging and Neural Dynamics Research Group, IRCCS San Camillo Hospital, Venice, Italy
| |
Collapse
|
19
|
Hilbert A, Ehlis AC. Neurowissenschaftlich fundierte Psychotherapie. PSYCHOTHERAPEUT 2019. [DOI: 10.1007/s00278-019-0355-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
20
|
Ghanavati E, Salehinejad MA, Nejati V, Nitsche MA. Differential role of prefrontal, temporal and parietal cortices in verbal and figural fluency: Implications for the supramodal contribution of executive functions. Sci Rep 2019; 9:3700. [PMID: 30842493 PMCID: PMC6403289 DOI: 10.1038/s41598-019-40273-7] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 02/11/2019] [Indexed: 12/17/2022] Open
Abstract
Verbal and figural fluency are related to executive functions (EFs), but the extent to which they benefit from executive resources and their respective cortical representations is not clear. Moreover, different brain areas and cognitive functions are involved in fluency processing. This study investigated effects of modulation of cortical excitability in the left dorsolateral prefrontal cortex (l-DLPFC), left temporal area and right posterior parietal cortex (r-PPC) with transcranial direct current stimulation (tDCS), on verbal and figural fluency. Fifteen healthy adult participants received anodal l-DLPFC (F3), anodal left temporal (T3), anodal r-PPC (P4) and sham tDCS (15 min, 1.5 mA). After five minutes of stimulation, participants underwent the verbal fluency (i.e., semantic and phonemic fluency tasks) and figural fluency tasks. Participants significantly generated more words with phonemic cues during anodal l-DLPFC tDCS and more words with semantic cues during both anodal left temporal and anodal l-DLPFC tDCS. In contrast, they generated more unique figures under anodal r-PPC and anodal l-DLPFC tDCS. Our results implicate that prefrontal regions and EFs are shared anatomical correlates and cognitive processes relevant for both, verbal and figural fluency (supramodal contribution of DLPFC activation), whereas r-PPC and left temporal cortex are more specifically involved in figural and semantic fluency (modality-specific contribution).
Collapse
Affiliation(s)
- Elham Ghanavati
- Department of Psychology, Islamic Azad University, Science & Research Branch, Tehran, Iran.,Department of Psychology and Neurosciences, Leibniz Research Centre for Working Environment and Human Factors, Dortmund, Germany
| | - Mohammad Ali Salehinejad
- Department of Psychology and Neurosciences, Leibniz Research Centre for Working Environment and Human Factors, Dortmund, Germany. .,Institute for Cognitive and Brain Sciences, Shahid Beheshti University, Tehran, Iran. .,International Graduate School of Neuroscience, Ruhr University Bochum, Bochum, Germany.
| | - Vahid Nejati
- Faculty of Psychology and Educational Sciences, Department of Psychology, Shahid Beheshti University, Tehran, Iran. .,Department of Psychology, University of Regensburg, Regensburg, Germany.
| | - 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, Bochum, Germany
| |
Collapse
|
21
|
Li LM, Violante IR, Leech R, Ross E, Hampshire A, Opitz A, Rothwell JC, Carmichael DW, Sharp DJ. Brain state and polarity dependent modulation of brain networks by transcranial direct current stimulation. Hum Brain Mapp 2019; 40:904-915. [PMID: 30378206 PMCID: PMC6387619 DOI: 10.1002/hbm.24420] [Citation(s) in RCA: 83] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 09/04/2018] [Accepted: 10/03/2018] [Indexed: 01/03/2023] Open
Abstract
Despite its widespread use in cognitive studies, there is still limited understanding of whether and how transcranial direct current stimulation (tDCS) modulates brain network function. To clarify its physiological effects, we assessed brain network function using functional magnetic resonance imaging (fMRI) simultaneously acquired during tDCS stimulation. Cognitive state was manipulated by having subjects perform a Choice Reaction Task or being at "rest." A novel factorial design was used to assess the effects of brain state and polarity. Anodal and cathodal tDCS were applied to the right inferior frontal gyrus (rIFG), a region involved in controlling activity large-scale intrinsic connectivity networks during switches of cognitive state. tDCS produced widespread modulation of brain activity in a polarity and brain state dependent manner. In the absence of task, the main effect of tDCS was to accentuate default mode network (DMN) activation and salience network (SN) deactivation. In contrast, during task performance, tDCS increased SN activation. In the absence of task, the main effect of anodal tDCS was more pronounced, whereas cathodal tDCS had a greater effect during task performance. Cathodal tDCS also accentuated the within-DMN connectivity associated with task performance. There were minimal main effects of stimulation on network connectivity. These results demonstrate that rIFG tDCS can modulate the activity and functional connectivity of large-scale brain networks involved in cognitive function, in a brain state and polarity dependent manner. This study provides an important insight into mechanisms by which tDCS may modulate cognitive function, and also has implications for the design of future stimulation studies.
Collapse
Affiliation(s)
- Lucia M. Li
- Computational, Cognitive, and Clinical Imaging Lab, Division of Brain Sciences, Department of MedicineImperial CollegeLondonUK
| | - Ines R. Violante
- Computational, Cognitive, and Clinical Imaging Lab, Division of Brain Sciences, Department of MedicineImperial CollegeLondonUK
- Sobell Department of Motor Neuroscience and Movement DisordersUCL Institute of Neurology, University College LondonLondonUK
- School of PsychologyUniversity of SurreyGuildfordUK
| | - Rob Leech
- Centre for Neuroimaging ScienceKings College LondonUK
| | - Ewan Ross
- Computational, Cognitive, and Clinical Imaging Lab, Division of Brain Sciences, Department of MedicineImperial CollegeLondonUK
| | - Adam Hampshire
- Computational, Cognitive, and Clinical Imaging Lab, Division of Brain Sciences, Department of MedicineImperial CollegeLondonUK
| | - Alexander Opitz
- Department of Biomedical EngineeringUniversity of MinnesotaMinneapolisMinnesota
| | - John C. Rothwell
- Sobell Department of Motor Neuroscience and Movement DisordersUCL Institute of Neurology, University College LondonLondonUK
| | - David W. Carmichael
- Centre for Neuroimaging ScienceKings College LondonUK
- Department of Biomedical EngineeringKings College LondonUK
| | - David J. Sharp
- Computational, Cognitive, and Clinical Imaging Lab, Division of Brain Sciences, Department of MedicineImperial CollegeLondonUK
| |
Collapse
|
22
|
Schwippel T, Papazova I, Strube W, Fallgatter AJ, Hasan A, Plewnia C. Beneficial effects of anodal transcranial direct current stimulation (tDCS) on spatial working memory in patients with schizophrenia. Eur Neuropsychopharmacol 2018; 28:1339-1350. [PMID: 30292415 DOI: 10.1016/j.euroneuro.2018.09.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 03/23/2018] [Accepted: 09/21/2018] [Indexed: 12/19/2022]
Abstract
Schizophrenia is a severe and often detrimental psychiatric disorder. The individual patients' level of functioning is essentially determined by cognitive, particularly working memory (WM), deficits that are critically linked to dysfunctional activity of the dorsolateral prefrontal cortex (dlPFC). Transcranial direct current stimulation (tDCS) can transiently modulate activity of the dlPFC and remote areas and has been shown to improve WM functions. It may therefore provide a new, targeted treatment option. For this aim, the present study investigated the effect of anodal tDCS of different intensities on spatial WM in patients with schizophrenia. In two experiments, 32 patients performed a spatial n-back task with increasing WM load (1-, 2-, and 3-back) at baseline and in two sessions with anodal or sham tDCS (EXP I [n = 16]: 1 mA; EXP II [n = 16]: 2 mA) to the right dlPFC (cathode: left m. deltoideus). With 1 mA anodal tDCS, no effect on WM performance could be detected. However, 2 mA anodal tDCS increased accuracy (measured by d') of the task with the highest WM load (3-back). This effect was larger in patients with a lower level of general neurocognitive functioning. These results demonstrate a beneficial effect of 2 mA anodal tDCS on deficient WM accuracy in patients with schizophrenia particularly under challenging conditions and in subjects with higher cognitive impairments. This data will inform future clinical trials on tDCS-enhanced cognitive training to improve treatment of schizophrenia.
Collapse
Affiliation(s)
- T Schwippel
- Department of Psychiatry and Psychotherapy, Neurophysiology & Interventional Neuropsychiatry, University of Tübingen, Calwerstrasse 14, 72076 Tübingen, Germany
| | - I Papazova
- Department of Psychiatry and Psychotherapy, Klinikum der Universität München, Ludwig-Maximilians University Munich, Nußbaumstraße 7, 80336 Munich, Germany
| | - W Strube
- Department of Psychiatry and Psychotherapy, Klinikum der Universität München, Ludwig-Maximilians University Munich, Nußbaumstraße 7, 80336 Munich, Germany
| | - A J Fallgatter
- Department of Psychiatry and Psychotherapy, Neurophysiology & Interventional Neuropsychiatry, University of Tübingen, Calwerstrasse 14, 72076 Tübingen, Germany
| | - A Hasan
- Department of Psychiatry and Psychotherapy, Klinikum der Universität München, Ludwig-Maximilians University Munich, Nußbaumstraße 7, 80336 Munich, Germany
| | - C Plewnia
- Department of Psychiatry and Psychotherapy, Neurophysiology & Interventional Neuropsychiatry, University of Tübingen, Calwerstrasse 14, 72076 Tübingen, Germany.
| |
Collapse
|
23
|
Ehlis AC, Barth B, Hudak J, Storchak H, Weber L, Kimmig ACS, Kreifelts B, Dresler T, Fallgatter AJ. Near-Infrared Spectroscopy as a New Tool for Neurofeedback Training: Applications in Psychiatry and Methodological Considerations. JAPANESE PSYCHOLOGICAL RESEARCH 2018. [DOI: 10.1111/jpr.12225] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
|
24
|
Klaus J, Schutter DJLG. Putting focus on transcranial direct current stimulation in language production studies. PLoS One 2018; 13:e0202730. [PMID: 30138361 PMCID: PMC6107198 DOI: 10.1371/journal.pone.0202730] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 08/08/2018] [Indexed: 11/24/2022] Open
Abstract
Previous language production studies targeting the inferior frontal and superior temporal gyrus using anodal tDCS have provided mixed results. Part of this heterogeneity may be explained by limited target region focality of conventionally used electrode montages. We examined the focality of conventionally and alternative electrode montages. Electrical field distributions of anodal tDCS targeting IFG and pSTG were simulated in conventional setups (anodal electrode over left IFG/pSTG, reference electrode over right supraorbital region) and an alternative electrode montage in four different brains. Conventional montages showed maximum field strengths outside of the target regions. Results from alternative electrode montages showed that focality of tDCS could be improved by adjustments in electrode placement. Heterogeneity of findings of language production studies deploying conventional montages may in part be explained by diffuse electrical field distributions. Alternative montages may improve focality and provide more unequivocal results.
Collapse
Affiliation(s)
- Jana Klaus
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands
- * E-mail:
| | - Dennis J. L. G. Schutter
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands
| |
Collapse
|
25
|
Non-invasive brain stimulation to investigate language production in healthy speakers: A meta-analysis. Brain Cogn 2018; 123:10-22. [DOI: 10.1016/j.bandc.2018.02.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 02/01/2018] [Accepted: 02/13/2018] [Indexed: 11/29/2022]
|
26
|
Westwood SJ, Romani C. Null Effects on Working Memory and Verbal Fluency Tasks When Applying Anodal tDCS to the Inferior Frontal Gyrus of Healthy Participants. Front Neurosci 2018; 12:166. [PMID: 29615855 PMCID: PMC5867342 DOI: 10.3389/fnins.2018.00166] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Accepted: 03/01/2018] [Indexed: 01/22/2023] Open
Abstract
Transcranial direct current stimulation (tDCS) is a technique used to modify cognition by modulating underlying cortical excitability via weak electric current applied through the scalp. Although many studies have reported positive effects with tDCS, a number of recent studies highlight that tDCS effects can be small and difficult to reproduce. This is especially the case when attempting to modulate performance using single applications of tDCS in healthy participants. Possible reasons may be that optimal stimulation parameters have yet to be identified, and that individual variation in cortical activity and/or level of ability confound outcomes. To address these points, we carried out a series of experiments in which we attempted to modulate performance in fluency and working memory probe tasks using stimulation parameters which have been associated with positive outcomes: we targeted the left inferior frontal gyrus (LIFG) and compared performance when applying a 1.5 mA anodal current for 25 min and with sham stimulation. There is evidence that LIFG plays a role in these tasks and previous studies have found positive effects of stimulation. We also compared our experimental group (N = 19–20) with a control group receiving no stimulation (n = 24). More importantly, we also considered effects on subgroups subdivided according to memory span as well as to more direct measures of executive function abilities and motivational levels. We found no systematic effect of stimulation. Our findings are in line with a growing body of evidence that tDCS produces unreliable effects. We acknowledge that our findings speak to the conditions we investigated, and that alternative protocols (e.g., multiple sessions, clinical samples, and different stimulation polarities) may be more effective. We encourage further research to explore optimal conditions for tDCS efficacy, given the potential benefits that this technique poses for understanding and enhancing cognition.
Collapse
Affiliation(s)
- Samuel J Westwood
- School of Life & Health Sciences, Aston University, Birmingham, United Kingdom
| | - Cristina Romani
- School of Life & Health Sciences, Aston University, Birmingham, United Kingdom
| |
Collapse
|
27
|
Transcranial electric stimulation (tES) and NeuroImaging: the state-of-the-art, new insights and prospects in basic and clinical neuroscience. Neuroimage 2018; 140:1-3. [PMID: 27633745 DOI: 10.1016/j.neuroimage.2016.08.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Transcranial electric stimulation (tES) of the brain has attracted an increased interest in recent years. Yet, despite remarkable research efforts to date, the underlying neurobiological mechanisms of tES' effects are still incompletely understood. This Special Issue aims to provide a comprehensive and up-to-date overview of the state-of-the-art in studies combining tES and neuroimaging, while introducing most recent insights and outlining future prospects related to this new and rapidly growing field. The findings reported here combine methodological advancements with insights into the underlying mechanisms of tES itself. At the same time, they also point to the many caveats and specific challenges associated with such studies, which can arise from both technical and biological sources. Besides promising to advance basic neuroscience, combined tES and neuroimaging studies may also substantially change previous conceptions about the methods of action of electric or magnetic stimulation on the brain.
Collapse
|
28
|
Prefrontal neuromodulation reverses spatial associations of non-numerical sequences, but not numbers. Biol Psychol 2017; 128:39-49. [DOI: 10.1016/j.biopsycho.2017.07.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Revised: 07/12/2017] [Accepted: 07/12/2017] [Indexed: 11/20/2022]
|
29
|
Taylor ST, Chhabra H, Sreeraj VS, Shivakumar V, Kalmady SV, Venkatasubramanian G. Neural Effects of Transcranial Direct Current Stimulation in Schizophrenia: A Case Study using Functional Near-infrared Spectroscopy. Indian J Psychol Med 2017; 39:691-694. [PMID: 29200573 PMCID: PMC5688904 DOI: 10.4103/ijpsym.ijpsym_238_17] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Schizophrenia is a severe neuropsychiatric disorder characterized by delusions, hallucinations, behavioral symptoms, and cognitive deficits. Roughly, 70%-80% of schizophrenia patients experience auditory verbal hallucinations (AVHs), with 25%-30% demonstrating resistance to conventional antipsychotic medications. Studies suggest a promising role for add-on transcranial direct current stimulation (tDCS) in the treatment of medication-refractory AVHs. The mechanisms through which tDCS could be therapeutic in such cases are unclear, but possibly involve neuroplastic effects. In recent years, functional near-infrared spectroscopy (fNIRS) has been used successfully to study tDCS-induced neuroplastic changes. In a double-blind, sham-controlled design, we applied fNIRS to measure task-dependent cerebral blood flow (CBF) changes as a surrogate outcome of single session tDCS-induced effects on neuroplasticity in a schizophrenia patient with persistent auditory hallucinations. The observations are discussed in this case report.
Collapse
Affiliation(s)
- S Trevor Taylor
- Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee, USA
| | - Harleen Chhabra
- Department of Psychiatry and Translational Psychiatry Laboratory, Neurobiology Research Centre, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India
| | - Vanteemar S Sreeraj
- Department of Psychiatry and Translational Psychiatry Laboratory, Neurobiology Research Centre, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India
| | - Venkataram Shivakumar
- Department of Psychiatry and Translational Psychiatry Laboratory, Neurobiology Research Centre, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India
| | - Sunil V Kalmady
- Department of Psychiatry and Translational Psychiatry Laboratory, Neurobiology Research Centre, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India
| | - Ganesan Venkatasubramanian
- Department of Psychiatry and Translational Psychiatry Laboratory, Neurobiology Research Centre, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India
| |
Collapse
|
30
|
Leite J, Gonçalves ÓF, Pereira P, Khadka N, Bikson M, Fregni F, Carvalho S. The differential effects of unihemispheric and bihemispheric tDCS over the inferior frontal gyrus on proactive control. Neurosci Res 2017; 130:39-46. [PMID: 28842243 DOI: 10.1016/j.neures.2017.08.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 08/14/2017] [Accepted: 08/18/2017] [Indexed: 01/19/2023]
Abstract
This study examined the effects of bihemispheric and unihemispheric transcranial Direct Current Stimulation (tDCS) over the inferior frontal gyrus (IFG) on proactive control. Sixteen participants were randomized to receive (i) bihemispheric tDCS, with a 35cm2 anodal electrode of the right IFG and a 35cm2 cathode electrode of left IFG or (ii) unihemispheric tDCS, with a 35cm2 anodal electrode of the right IFG and a 100cm2 electrode of the left IFG or (iii) sham tDCS, while performing a prepotent inhibition task. There were significant speed-accuracy tradeoff effects in terms of switch costs: unihemispheric tDCS significantly decreased the accuracy when compared to bihemispheric, and sham tDCS, while increased response time when comparing to bihemispheric and sham tDCS. The computational model showed a symmetrical field intensity for the bihemispheric tDCS montage, and an asymmetrical for the unihemispheric tDCS montage. This study confirms that unihemispheric tDCS over the rIFG has a significant impact on response inhibition. The lack of results of bihemispheric tDCS brings two important findings for this study: (i) left IFG seems to be also critically associated with inhibitory response control, and (ii) these results highlight the importance of considering the dual effects of tDCS when choosing the electrode montage.
Collapse
Affiliation(s)
- Jorge Leite
- Neuropsychophysiology Laboratory, CIPsi, School of Psychology (EPsi), University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal; Univ Portucalense, Portucalense Institute for Human Development - INPP, Oporto, Portugal; Spaulding Neuromodulation Center, Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
| | - Óscar F Gonçalves
- Neuropsychophysiology Laboratory, CIPsi, School of Psychology (EPsi), University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal; Spaulding Neuromodulation Center, Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Patrícia Pereira
- Neuropsychophysiology Laboratory, CIPsi, School of Psychology (EPsi), University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - Niranjan Khadka
- Department of Biomedical Engineering, The City College of New York of CUNY, New York, NY, 10031 USA
| | - Marom Bikson
- Department of Biomedical Engineering, The City College of New York of CUNY, New York, NY, 10031 USA
| | - Felipe Fregni
- Spaulding Neuromodulation Center, Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Sandra Carvalho
- Neuropsychophysiology Laboratory, CIPsi, School of Psychology (EPsi), University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal; Spaulding Neuromodulation Center, Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| |
Collapse
|
31
|
Muthalib M, Besson P, Rothwell J, Perrey S. Focal Hemodynamic Responses in the Stimulated Hemisphere During High-Definition Transcranial Direct Current Stimulation. Neuromodulation 2017; 21:348-354. [PMID: 28714545 DOI: 10.1111/ner.12632] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 05/01/2017] [Accepted: 05/25/2017] [Indexed: 12/01/2022]
Abstract
OBJECTIVE High-definition transcranial direct current stimulation (HD-tDCS) using a 4 × 1 electrode montage has been previously shown using modeling and physiological studies to constrain the electric field within the spatial extent of the electrodes. The aim of this proof-of-concept study was to determine if functional near-infrared spectroscopy (fNIRS) neuroimaging can be used to determine a hemodynamic correlate of this 4 × 1 HD-tDCS electric field on the brain. MATERIALS AND METHODS In a three session cross-over study design, 13 healthy males received one sham (2 mA, 30 sec) and two real (HD-tDCS-1 and HD-tDCS-2, 2 mA, 10 min) anodal HD-tDCS targeting the left M1 via a 4 × 1 electrode montage (anode on C3 and 4 return electrodes 3.5 cm from anode). The two real HD-tDCS sessions afforded a within-subject replication of the findings. fNIRS was used to measure changes in brain hemodynamics (oxygenated hemoglobin integral-O2 Hbint ) during each 10 min session from two regions of interest (ROIs) in the stimulated left hemisphere that corresponded to "within" (Lin ) and "outside" (Lout ) the spatial extent of the 4 × 1 electrode montage, and two corresponding ROIs (Rin and Rout ) in the right hemisphere. RESULTS The ANOVA showed that both real anodal HD-tDCS compared to sham induced a significantly greater O2 Hbint in the Lin than Lout ROIs of the stimulated left hemisphere; while there were no significant differences between the real and sham sessions for the right hemisphere ROIs. Intra-class correlation coefficients showed "fair-to-good" reproducibility for the left stimulated hemisphere ROIs. CONCLUSIONS The greater O2 Hbint "within" than "outside" the spatial extent of the 4 × 1 electrode montage represents a hemodynamic correlate of the electrical field distribution, and thus provides a prospective reliable method to determine the dose of stimulation that is necessary to optimize HD-tDCS parameters in various applications.
Collapse
Affiliation(s)
| | - Pierre Besson
- EuroMov, University of Montpellier, Montpellier, France
| | - John Rothwell
- Institute of Neurology, University College London, London, UK
| | | |
Collapse
|
32
|
Metzger FG, Schopp B, Haeussinger FB, Dehnen K, Synofzik M, Fallgatter AJ, Ehlis AC. Brain activation in frontotemporal and Alzheimer's dementia: a functional near-infrared spectroscopy study. ALZHEIMERS RESEARCH & THERAPY 2016; 8:56. [PMID: 27931245 PMCID: PMC5146884 DOI: 10.1186/s13195-016-0224-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Accepted: 11/16/2016] [Indexed: 12/12/2022]
Abstract
Background Frontotemporal dementia is an increasingly studied disease, the underlying functional impairments on a neurobiological level of which have not been fully understood. Patients with the behavioral-subtype frontotemporal dementia (bvFTD) are particularly challenging for clinical measurements such as functional imaging due to their behavioral symptoms. Here, an alternative imaging method, functional near-infrared spectroscopy (fNIRS), is introduced to measure task-related cortical brain activation based on blood oxygenation. The current study investigated differences in cortical activation patterns of patients with bvFTD, Alzheimer’s dementia (AD), and healthy elderly subjects measured by fNIRS. Method Eight probable bvFTD patients completed the semantic, phonological, and control conditions of a verbal fluency task. Eight AD patients and eight healthy controls were compared on the same task. Simultaneously, an fNIRS measurement was conducted and analyzed using a correction method based on the expected negative correlation between oxygenated and deoxygenated hemoglobin. Results Healthy controls show an increase in cortical activation measured in frontoparietal areas such as the dorsolateral prefrontal cortex. The activation pattern of patients with AD is similar, but weaker. In contrast, bvFTD patients show a more frontopolar pattern, with activation of Broca’s area, instead of the dorsolateral prefrontal cortex and the superior temporal gyrus. The frontoparietal compensation mechanisms, seen in the healthy elderly, were missing in bvFTD patients. Conclusion Different frontoparietal cortical activation patterns may indicate a correlate of diverse pathophysiological mechanisms of AD and bvFTD during verbal fluency processing. The AD pattern is weaker and more similar to the healthy pattern, whereas the bvFTD pattern is qualitatively different, namely more frontopolar and without frontoparietal compensation activation. It adheres to a change of cortical activation during the course of the disease. Electronic supplementary material The online version of this article (doi:10.1186/s13195-016-0224-8) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Florian G Metzger
- Department of Psychiatry and Psychotherapy, University Hospital of Tuebingen, Calwerstraße 14, 72076, Tuebingen, Germany. .,Geriatric Center at the University Hospital of Tuebingen, Calwerstraße 14, 72076, Tuebingen, Germany.
| | - Betti Schopp
- Department of Psychiatry and Psychotherapy, University Hospital of Tuebingen, Calwerstraße 14, 72076, Tuebingen, Germany
| | - Florian B Haeussinger
- Department of Psychiatry and Psychotherapy, University Hospital of Tuebingen, Calwerstraße 14, 72076, Tuebingen, Germany
| | - Katja Dehnen
- Department of Psychiatry and Psychotherapy, University Hospital of Tuebingen, Calwerstraße 14, 72076, Tuebingen, Germany
| | - Matthis Synofzik
- Center of Neurology, Department of Neurodegeneration and Hertie Institute for Clinical Brain Research, University Hospital of Tuebingen, Hoppe-Seyler-Straße 3, 72076, Tuebingen, Germany.,German Center of Neurodegenerative Disorders (DZNE), University Hospital of Tuebingen, Otfried-Müller-Straße 23, 72076, Tuebingen, Germany
| | - Andreas J Fallgatter
- Department of Psychiatry and Psychotherapy, University Hospital of Tuebingen, Calwerstraße 14, 72076, Tuebingen, Germany.,German Center of Neurodegenerative Disorders (DZNE), University Hospital of Tuebingen, Otfried-Müller-Straße 23, 72076, Tuebingen, Germany
| | - Ann-Christine Ehlis
- Department of Psychiatry and Psychotherapy, University Hospital of Tuebingen, Calwerstraße 14, 72076, Tuebingen, Germany
| |
Collapse
|
33
|
Effects of HD-tDCS on memory and metamemory for general knowledge questions that vary by difficulty. Brain Stimul 2016; 10:231-241. [PMID: 27876306 DOI: 10.1016/j.brs.2016.10.013] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 10/24/2016] [Accepted: 10/28/2016] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND The ability to monitor one's own memory is an important feature of normal memory and is an aspect of 'metamemory'. Lesion studies have shown dissociations between memory and metamemory, but only single dissociations have been shown using transcranial direct current stimulation (tDCS). One potential reason that only single dissociations have been shown is that tDCS effects may be moderated by task difficulty. OBJECTIVE/HYPOTHESIS We used high definition (HD) tDCS to test for dissociable roles of the dorsolateral prefrontal cortex (DLPFC) and anterior temporal lobe (ATL) in semantic long-term memory and metamemory tasks. We also tested whether general knowledge question difficulty moderated the effects of HD-tDCS. METHODS Across 3 sessions, participants received active HD-tDCS over the left DLPFC or left ATL, or sham HD-tDCS during general knowledge recall and recognition tests, and a 'feeling-of-knowing' metamemory task. General knowledge questions were blocked by difficulty. Repeated measures ANOVAs were used to examine the effects of HD-tDCS on memory and metamemory tasks by memory question difficulty. RESULTS HD-tDCS over the ATL led to improved recall compared to DLPFC and sham HD-tDCS, and this occurred only for medium difficulty questions. In contrast, for non-recalled questions, HD-tDCS over the DLPFC led to improved recognition accuracy and improved feeling-of-knowing accuracy compared to ATL and sham HD-tDCS, and this was not moderated by memory question difficulty. CONCLUSION (S) HD-tDCS can be used to dissociate the roles of the ATL and DLPFC in different memory and 'metamemory' tasks. The effects of HD-tDCS on task may be moderated by task difficulty, depending on the nature of the task and site of stimulation.
Collapse
|
34
|
Joyal M, Fecteau S. Transcranial Direct Current Stimulation Effects on Semantic Processing in Healthy Individuals. Brain Stimul 2016; 9:682-691. [DOI: 10.1016/j.brs.2016.05.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 05/05/2016] [Accepted: 05/08/2016] [Indexed: 11/15/2022] Open
|