Transcranial direct current stimulation modulates pattern separation
Neuroreport 2016 DOI: 10.1097/WNR.0000000000000621
Marcus Cappiello, Weizhen Xie, Alexander David, Marom Bikson and Weiwei Zhang
Abstract: Maintaining similar memories in a distinct and nonoverlapping manner, known as pattern separation, is an important mnemonic process. The medial temporal lobe, especially the hippocampus, has been implicated in this crucial memory function. The present study thus examines whether it is possible to modulate pattern separation using bilateral transcranial direct current stimulation (tDCS) over the temporal lobes. Specifically, in this study, pattern separation was assessed using the Mnemonic Similarity Task following 15-min offline bilateral temporal lobe tDCS (left cathode and right anode or left anode and right cathode) or sham stimulation. In the Mnemonic Similarity Task, participants studied a series of sequentially presented visual objects. In the subsequent recognition memory test, participants viewed a series of sequentially presented objects that could be old images from study, novel foils, or lures that were visually similar to the studied images. Participants reported whether these images were exactly the same as, similar to, or different from the studied images. Following both active tDCS conditions, participants were less likely to identify lures as ‘similar’ compared with the sham condition, indicating a reduction in pattern separation resulting from temporal lobe tDCS. In contrast, no significant difference in overall accuracy was found for participants’ discrimination of old and new images. Together, these results suggest that temporal lobe tDCS can selectively modulate the pattern separation function without changing participants’ baseline recognition memory performance.
Dr. Marom Bikson lectures at the National Institutes of Health (NIH) National Cancer Institute (NCI)
6/13/2016 NCI Shady Grove Campus Room TE406 9:30 AM
Medical Device Device for Innovative Cancer Therapies: Preclinical Evaluation, Clinical Trial Preparation, and a Prospective Clinical Trial of Intraoperative Real-Time Tissue Oxygenation Monitoring by Wireless Pulse Oximetry
Gozde Unal MS in Biomedical Engineering 2016 (mentor Marom Bikson)
Asif Rahman PhD in Biomedical Engineering 2016 (mentor Marom Bikson)
Alam M, Truong DQ, Khadka N , Bikson M
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Download: PDF Published in Physics in Medicine & Biology DOI
Abstract:
Transcranial direct current stimulation (tDCS) is a non-invasive neuromodulation technique that applies low amplitude current via electrodes placed on the scalp. Rather than directly eliciting a neuronal response, tDCS is believed to modulate excitability—enhancing or suppressing neuronal activity in regions of the brain depending on the polarity of stimulation. The specificity of tDCS to any therapeutic application derives in part from how electrode configuration determines the brain regions that are stimulated. Conventional tDCS uses two relatively large pads (>25 cm2) whereas high-definition tDCS (HD-tDCS) uses arrays of smaller electrodes to enhance brain targeting. The 4 × 1 concentric ring HD-tDCS (one center electrode surrounded by four returns) has been explored in application where focal targeting of cortex is desired. Here, we considered optimization of concentric ring HD-tDCS for targeting: the role of electrodes in the ring and the ring’s diameter. Finite element models predicted cortical electric field generated during tDCS. High resolution MRIs were segmented into seven tissue/material masks of varying conductivities. Computer aided design (CAD) model of electrodes, gel, and sponge pads were incorporated into the segmentation. Volume meshes were generated and the Laplace equation ( (σ V) = 0) was solved for cortical electric field, which was interpreted using physiological assumptions to correlate with stimulation and modulation. Cortical field intensity was predicted to increase with increasing ring diameter at the cost of focality while uni-directionality decreased. Additional surrounding ring electrodes increased uni-directionality while lowering cortical field intensity and increasing focality; though, this effect saturated and more than 4 surround electrode would not be justified. Using a range of concentric HD-tDCS montages, we showed that cortical region of influence can be controlled while balancing other design factors such as intensity at the target and uni-directionality. Furthermore, the evaluated concentric HD-tDCS approaches can provide categorical improvements in targeting compared to conventional tDCS. Hypothesis driven clinical trials, based on specific target engagement, would benefit by this more precise method of stimulation that could avoid potentially confounding brain regions.
Neuromodulation: Technology at the Neural Interface doi: 10.1111/ner.12430
Transcranial Direct Current Stimulation Is Feasible for Remotely Supervised Home Delivery in Multiple Sclerosis
Margaret Kasschau; Jesse Reisner; Kathleen Sherman; Marom Bikson; Abhishek Datta; Leigh E. Charvet
Objectives: Transcranial direct current stimulation (tDCS) has potential clinical application for symptomatic management in mul- tiple sclerosis (MS). Repeated sessions are necessary in order to adequately evaluate a therapeutic effect. However, it is not feasible for many individuals with MS to visit clinic for treatment on a daily basis, and clinic delivery is also associated with sub- stantial cost. We developed a research protocol to remotely supervise self- or proxy-administration for home delivery of tDCS using specially designed equipment and a telemedicine platform.
Materials and Methods: We targeted ten treatment sessions across two weeks. Twenty participants (n 5 20) diagnosed with MS (any subtype), ages 30 to 69 years with a range of disability (Expanded Disability Status Scale or EDSS scores of 1.0 to 8.0) were enrolled to test the feasibility of the remotely supervised protocol.
Results: Protocol adherence exceeded what has been observed in studies with clinic-based treatment delivery, with all but one participant (95%) completing at least eight of the ten sessions. Across a total of 192 supervised treatment sessions, no session required discontinuation and no adverse events were reported. The most common side effects were itching/tingling at the elec- trode site.
Conclusions: This remotely supervised tDCS protocol provides a method for safe and reliable delivery of tDCS for clinical studies in MS and expands patient access to tDCS.
Effects of High-Definition and Conventional tDCS on Response Inhibition
Brain Stimulation doi:10.1016/j.brs.2016.04.015. Read the full PDF
J. Hogeveen , J. Grafman , M. Aboseria , A. David , M. Bikson , K.K. Hauner
ABSTRACT Background: Response inhibition is a critical executive function, enabling the adaptive control of behavior in a changing environment. The inferior frontal cortex (IFC) is considered to be critical for response inhibition, leading researchers to develop transcranial direct current stimulation (tDCS) montages attempting to target the IFC and improve inhibitory performance. However, conventional tDCS montages produce diffuse current through the brain, making it difficult to establish causality between stimulation of any one given brain region and resulting behavioral changes. Recently, high-definition tDCS (HDtDCS) methods have been developed to target brain regions with increased focality relative to conventional tDCS. Objective: Remarkably few studies have utilized HD-tDCS to improve cognitive task performance, however, and no study has directly compared the behavioral effects of HD-tDCS to conventional tDCS. Methods: In the present study, participants received either HD-tDCS or conventional tDCS to the IFC during performance of a response inhibition task (stop-signal task, SST) or a control task (choice reaction time task, CRT). A third group of participants completed the same behavioral protocols, but received tDCS to a control site (mid-occipital cortex). Post-stimulation improvement in SST performance was analyzed as a function of tDCS group and the task performed during stimulation using both conventional and Bayesian parameter estimation analyses. Results: Bayesian estimation of the effects of HD- and conventional tDCS to IFC relative to control site stimulation demonstrated enhanced response inhibition for both conditions. No improvements were found after control task (CRT) training in any tDCS condition. Conclusion: Results support the use of both HD- and conventional tDCS to the IFC for improving response inhibition, providing empirical evidence that HD-tDCS can be used to facilitate performance on an executive function task.
A simple method for EEG guided transcranial electrical stimulation without models
Andrea Cancelli , Carlo Cottone , Franca Tecchio , Dennis Q Truong , Jacek Dmochowski and Marom Bikson
J. Neural Eng. 13 (2016) 036022
Full PDF: 2016 Cancelli A simple method
Abstract: Objective. There is longstanding interest in using EEG measurements to inform transcranial Electrical Stimulation (tES) but adoption is lacking because users need a simple and adaptable recipe. The conventional approach is to use anatomical head-models for both source localization (the EEG inverse problem) and current flow modeling (the tES forward model), but this approach is computationally demanding, requires an anatomical MRI, and strict assumptions about the target brain regions. We evaluate techniques whereby tES dose is derived from EEG without the need for an anatomical head model, target assumptions, difficult case-by-case conjecture, or many stimulation electrodes. Approach. We developed a simple two-step approach to EEG-guided tES that based on the topography of the EEG: (1) selects locations to be used for stimulation; (2) determines current applied to each electrode. Each step is performed based solely on the EEG with no need for head models or source localization. Cortical dipoles represent idealized brain targets. EEG-guided tES strategies are verified using a finite element method simulation of the EEG generated by a dipole, oriented either tangential or radial to the scalp surface, and then simulating the tES-generated electric field produced by each model-free technique. These model-free approaches are compared to a ‘gold standard’ numerically optimized dose of tES that assumes perfect understanding of the dipole location and head anatomy. We vary the number of electrodes from a few to over three hundred, with focality or intensity as optimization criterion. Main results. Model-free approaches evaluated include (1) voltage-to-voltage, (2) voltage-to-current; (3) Laplacian; and two Ad-Hoc techniques (4) dipole sink-to-sink; and (5) sink to concentric. Our results demonstrate that simple ad hoc approaches can achieve reasonable targeting for the case of a cortical dipole, remarkably with only 2–8 electrodes and no need for a model of the head. Significance. Our approach is verified directly only for a theoretically localized source, but may be potentially applied to an arbitrary EEG topography. For its simplicity and linearity, our recipe for model-free EEG guided tES lends itself to broad adoption and can be applied to static (tDCS), time-variant (e.g., tACS, tRNS, tPCS), or closed-loop tES.
Nature Scientific Reports Full paper link PDF: srep25160
Selective alteration of human value decisions with medial frontal tDCS is predicted by changes in attractor dynamics
D. Hämmerer, J. Bonaiuto, M. Klein-Flügge, M. Bikson & S. Bestmann
Scientific Reports 6, Article number: 25160 (2016)
doi:10.1038/srep25160
Abstract:During value-based decision making, ventromedial prefrontal cortex (vmPFC) is thought to support choices by tracking the expected gain from different outcomes via a competition-based process. Using a computational neurostimulation approach we asked how perturbing this region might alter this competition and resulting value decisions. We simulated a perturbation of neural dynamics in a biophysically informed model of decision-making through in silico depolarization at the level of neuronal ensembles. Simulated depolarization increased baseline firing rates of pyramidal neurons, which altered their susceptibility to background noise, and thereby increased choice stochasticity. These behavioural predictions were compared to choice behaviour in healthy participants performing similar value decisions during transcranial direct current stimulation (tDCS), a non-invasive brain stimulation technique. We placed the soma depolarizing electrode over medial frontal PFC. In line with model predictions, this intervention resulted in more random choices. By contrast, no such effect was observed when placing the depolarizing electrode over lateral PFC. Using a causal manipulation of ventromedial and lateral prefrontal function, these results provide support for competition-based choice dynamics in human vmPFC, and introduce computational neurostimulation as a mechanistic assay for neurostimulation studies of cognition.
Andoni has been working under the supervision of Dr. Marom Bikson for over 3 years. In that time he has published several papers, presented at national scientific meetings, and won several prestigious national awards including the Goldwater Scholarship (the 3rd from the Bikson lab). Andoni: We are very proud of all you have accomplished and all you will!!!
Dr. Marom Bikson quoted on his tDCS research in Science. Link
Cadaver study casts doubts on how zapping brain may boost mood, relieve pain. April 20, 2016.
Neuromodulation (S Taylor, Section Editor) Current Behavioral Neuroscience Reports pp 1-7
Current Status of Transcranial Direct Current Stimulation in Posttraumatic Stress and Other Anxiety Disorders
Benjamin M. Hampstead , Emily M. Briceño, Nathan Mascaro, Andoni Mourdoukoutas, Marom Bikson
10.1007/s40473-016-0070-9
Full PDF: Hampstead_tDCS_PTSD_Status
Abstract: Several empirically supported treatments have been identified for posttraumatic stress disorder (PTSD), yet a sizable number of patients are either unable to tolerate these approaches or remain symptomatic following treatment. Transcranial direct current stimulation (tDCS) is a well-tolerated method of modulating neuronal excitability that may hold promise as a novel intervention in PTSD and related disorders. The current review summarizes literature on the disrupted neural circuitry in PTSD and discusses the rationale for the commonly targeted prefrontal cortex (PFC) as it relates to PTSD. We then review the few prior (case) studies that have evaluated tDCS in patients with PTSD (1 study) and other anxiety disorders (4 studies). There was considerable variability in both the methods/justification for selecting the targeted brain region(s) and the tDCS montage used, which obscured any clear trends in the data. Finally, we describe the rationale for our ongoing study that specifically targets the lateral temporal cortex as a method of treating the symptoms of hyperarousal and re-experiencing in PTSD. Overall, it is clear that additional work is needed to establish dosing (e.g., intensity and duration of sessions, number of sessions) and optimal treatment targets, as well as to identify synergistic effects with existing treatments.
Polarity-Dependent Misperception of Subjective Visual Vertical during and after Transcranial Direct Current Stimulation (tDCS)
PLoS ONE 11(3): e0152331. doi:10.1371/journal.pone.0152331
Free online here
Taiza E. G. Santos-Pontelli 1*, Brunna P. Rimoli 1, Diandra B. Favoretto 1, Suleimy C. Mazin 1, Dennis Q. Truong 2, Joao P. Leite 1, Octavio M. Pontes-Neto 1, Suzanne R. Babyar 3, Michael Reding 3, Marom Bikson 2, Dylan J. Edwards 3
1 Department of Neuroscience and Behavioral Sciences, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, SP, Brazil, 2 Neural Engineering Laboratory, Department of Biomedical Engineering, The City College of New York of the City University of New York, New York, New York, United States of America, 3 Non-invasive Brain Stimulation and Human Motor Control Laboratory, Burke Medical Research Institute, White Plains, New York, United States of America; Neurology Department, Weill Medical College, Cornell University, New York, New York, United States of America
Abstract: Pathologic tilt of subjective visual vertical (SVV) frequently has adverse functional conse- quences for patients with stroke and vestibular disorders. Repetitive transcranial magnetic stimulation (rTMS) of the supramarginal gyrus can produce a transitory tilt on SVV in healthy subjects. However, the effect of transcranial direct current stimulation (tDCS) on SVV has never been systematically studied. We investigated whether bilateral tDCS over the tempo- ral-parietal region could result in both online and offline SVV misperception in healthy sub- jects. In a randomized, sham-controlled, single-blind crossover pilot study, thirteen healthy subjects performed tests of SVV before, during and after the tDCS applied over the tempo- ral-parietal region in three conditions used on different days: right anode/left cathode; right cathode/left anode; and sham. Subjects were blind to the tDCS conditions. Montage-spe- cific current flow patterns were investigated using computational models. SVV was signifi- cantly displaced towards the anode during both active stimulation conditions when compared to sham condition. Immediately after both active conditions, there were rebound effects. Longer lasting after-effects towards the anode occurred only in the right cathode/left anode condition. Current flow models predicted the stimulation of temporal-parietal regions under the electrodes and deep clusters in the posterior limb of the internal capsule. The present findings indicate that tDCS over the temporal-parietal region can significantly alter human SVV perception. This tDCS approach may be a potential clinical tool for the treat- ment of SVV misperception in neurological patients.
Full conference details here
Dr. Bikson to speak on April 7th.
Update: Our article on sport performance in athletics features in Nature. Link to news feature.
Complete original paper: pubmed link Full PDF: tDCS_autonomic_Paper
Br J Sports Med. 2013 Feb 27. [Epub ahead of print]
Brain stimulation modulates the autonomic nervous system, rating of perceived exertion and performance during maximal exercise.
Okano AH, Fontes EB, Montenegro RA, Farinatti PD, Cyrino ES, Li LM, Bikson M, Noakes TD.
BACKGROUND: The temporal and insular cortex (TC, IC) have been associated with autonomic nervous system (ANS) control and the awareness of emotional feelings from the body. Evidence shows that the ANS and rating of perceived exertion (RPE) regulate exercise performance. Non-invasive brain stimulation can modulate the cortical area directly beneath the electrode related to ANS and RPE, but it could also affect subcortical areas by connection within the cortico-cortical neural networks. This study evaluated the effects of transcranial direct current stimulation (tDCS) over the TC on the ANS, RPE and performance during a maximal dynamic exercise.
METHODS: Ten trained cyclists participated in this study (33±9 years; 171.5±5.8 cm; 72.8±9.5 kg; 10-11 training years). After 20-min of receiving either anodal tDCS applied over the left TC (T3) or sham stimulation, subjects completed a maximal incremental cycling exercise test. RPE, heart rate (HR) and R-R intervals (as a measure of ANS function) were recorded continuously throughout the tests. Peak power output (PPO) was recorded at the end of the tests.
RESULTS: With anodal tDCS, PPO improved by ∼4% (anodal tDCS: 313.2±29.9 vs 301.0±19.8 watts: sham tDCS; p=0.043), parasympathetic vagal withdrawal was delayed (anodal tDCS: 147.5±53.3 vs 125.0±35.4 watts: sham tDCS; p=0.041) and HR was reduced at submaximal workloads. RPE also increased more slowly during exercise following anodal tDCS application, but maximal RPE and HR values were not affected by cortical stimulation.
CONCLUSIONS: The findings suggest that non-invasive brain stimulation over the TC modulates the ANS activity and the sensory perception of effort and exercise performance, indicating that the brain plays a crucial role in the exercise performance regulation.
Schizophr Res. 2015 Aug;166(1-3):362-3. doi: 10.1016/j.schres.2015.05.029.
Targeting negative symptoms in schizophrenia: results from a proof-of-concept trial assessing prefrontal anodic tDCS protocol.
Kurimori M, Shiozawa P, Bikson M, Aboseria M, Cordeiro Q.
Full paper: kurimori2015 Pubmed link
“….In the present study anodic tDCS protocol was found to ameliorate negative symptoms in schizophrenia. The present results need to be taken as hypothesis-driven given the study design. Limitations to this study include its unblinded nature, small sample size, lack of a control group, and short length. Moreover, our results may be overestimated due to intrinsic characteristics such as the placebo effect and Hawthorne effect. However, the current “proof-of-concept” trial is aimed at evaluat- ing preliminary effects of a new experimental tDCS protocol. We under- stand that the trends seen in the completers shall strongly justify a larger double-blind study with better estimation of sample size.”
Arthritis Rheumatol. 2015 Feb;67(2):576-81.
Excitatory and inhibitory brain metabolites as targets of motor cortex transcranial direct current stimulation therapy and predictors of its efficacy in fibromyalgia.
Foerster BR, Nascimento TD, DeBoer M, Bender MA, Rice IC, Truong DQ, Bikson M, Clauw DJ, Zubieta JK, Harris RE, DaSilva AF.
Paper PDF: Foerster_et_al-2015-Arthritis_&_Rheumatology Journal link here
Abstract: OBJECTIVE: Transcranial direct current stimulation (tDCS) has been shown to improve pain symptoms in fibromyalgia (FM), a central pain syndrome whose underlying mechanisms are not well understood. This study was undertaken to explore the neurochemical action of tDCS in the brain of patients with FM, using proton magnetic resonance spectroscopy (1H-MRS). METHODS: Twelve patients with FM underwent sham tDCS over the left motor cortex (anode placement) and contralateral supraorbital cortex (cathode placement) for 5 consecutive days, followed by a 7-day washout period and then active tDCS for 5 consecutive days. Clinical pain assessment and 1H-MRS testing were performed at baseline, the week following the sham tDCS trial, and the week following the active tDCS trial. RESULTS: Clinical pain scores decreased significantly between the baseline and active tDCS time points (P = 0.04). Levels of glutamate + glutamine (Glx) in the anterior cingulate were significantly lower at the post–active tDCS assessment compared with the post–sham tDCS assessment (P = 0.013), and the decrease in Glx levels in the thalami between these time points approached significance (P = 0.056). From baseline to the post–sham tDCS assessment, levels of N-acetylaspartate (NAA) in the posterior insula increased significantly (P = 0.015). There was a trend toward increased levels of γ-aminobutyric acid (GABA) in the anterior insula after active tDCS, compared with baseline (P = 0.064). Baseline anterior cingulate Glx levels correlated significantly with changes in pain score, both for the time period from baseline to sham tDCS (β1 = 1.31, P < 0.001) and for the time period from baseline to active tDCS (β1= 1.87, P < 0.001). CONCLUSION: The present findings suggest that GABA, Glx, and NAA play an important role in the pathophysiology of FM and its modulation by tDCS.