Modeling the current density generated by transcutaneous spinal direct current stimulation (tsDCS)

AbstractTranscranial direct current stimulation (tDCS) have revealed the capability to augment various types of behavioural interventions. We aimed to augment the effects of mindfulness, suggested for reducing anxiety, with concurrent use of tDCS. We conducted a double-blind randomized study with 58 healthy individuals. We introduced treadmill walking for focused meditation and active or sham tDCS on the left dorsolateral prefrontal cortex for 20 min. We evaluated outcomes using State-Trait Anxiety Inventory-State Anxiety (STAI) before the intervention as well as immediately, 60 min, and 1 week after the intervention, and current density from electroencephalograms (EEG) before and after the intervention. The linear mixed-effect models demonstrated that STAI-state anxiety showed a significant interaction effect between 1 week after the intervention and tDCS groups. As for alpha-band EEG activity, the current density in the rostral anterior cingulate cortex (rACC) was significantly reduced in the active compared with the sham stimulation group, and a significant correlation was seen between changes in STAI-trait anxiety and the current density of the rACC in the active stimulation group. Our study provided that despite this being a one-shot and short intervention, the reduction in anxiety lasts for one week, and EEG could potentially help predict its anxiolytic effect.

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𝓲-SATA: A MATLAB based toolbox to estimate Current Density generated by Transcranial Direct Current Stimulation in an Individual Brain

10.1101/2020.05.28.120774 ◽

2020 ◽

Author(s):

Rajan Kashyap ◽

Sagarika Bhattacharjee ◽

Ramaswamy Arumugam ◽

Kenichi Oishi ◽

John E. Desmond ◽

...

Keyword(s):

Direct Current ◽

Current Density ◽

Transcranial Direct Current Stimulation ◽

Anterior Commissure ◽

Weak Current ◽

Posterior Commissure ◽

Direct Current Stimulation ◽

Total Current Density ◽

Magnetic Resonance Imaging Mri ◽

The Brain

AbstractBackgroundTranscranial Direct Current Stimulation (tDCS) is a technique where a weak current is passed through the electrodes placed on the scalp. The distribution of the electric current induced in the brain due to tDCS is provided by simulation toolbox like Realistic-volumetric-Approach-based-Simulator-for-Transcranial-electric-stimulation (ROAST). However, the procedure to estimate the total current density induced at the target and the intermediary region of the cortex is complex. The Systematic-Approach-for-tDCS-Analysis (SATA) was developed to overcome this problem. However, SATA is limited to standardized headspace only. Here we develop individual-SATA (𝓲-SATA) to extend it to individual head.MethodT1-weighted images of 15 subjects were taken from two Magnetic Resonance Imaging (MRI) scanners of different strengths. Across the subjects, the montages were simulated in ROAST. 𝓲-SATA converts the ROAST output to Talairach space. The x, y and z coordinates of the anterior commissure (AC), posterior commissure (PC), and Mid-Sagittal (MS) points are necessary for the conversion. AC and PC are detected using the acpcdetect toolbox. We developed a method to determine the MS in the image and cross-verified its location manually using BrainSight®.ResultDetermination of points with 𝓲-SATA is fast and accurate. The 𝓲-SATA provided estimates of the current-density induced across an individual’s cortical lobes and gyri as tested on images from two different scanners.ConclusionResearchers can use 𝓲-SATA for customizing tDCS-montages. With 𝓲-SATA it is also easier to compute the inter-individual variation in current-density across the target and intermediary regions of the brain. The software is publicly available.

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Multifocal Transcranial Direct Current Stimulation Modulates Resting-State Functional Connectivity in Older Adults Depending on the Induced Current Density

Frontiers in Aging Neuroscience ◽

10.3389/fnagi.2021.725013 ◽

2021 ◽

Vol 13 ◽

Author(s):

Kilian Abellaneda-Pérez ◽

Lídia Vaqué-Alcázar ◽

Ruben Perellón-Alfonso ◽

Cristina Solé-Padullés ◽

Núria Bargalló ◽

...

Keyword(s):

Older Adults ◽

Electric Current ◽

Direct Current ◽

Current Density ◽

Transcranial Direct Current Stimulation ◽

Resting State ◽

Electric Current Density ◽

Direct Current Stimulation ◽

Induced Changes ◽

The Brain

Combining non-invasive brain stimulation (NIBS) with resting-state functional magnetic resonance imaging (rs-fMRI) is a promising approach to characterize and potentially optimize the brain networks subtending cognition that changes as a function of age. However, whether multifocal NIBS approaches are able to modulate rs-fMRI brain dynamics in aged populations, and if these NIBS-induced changes are consistent with the simulated electric current distribution on the brain remains largely unknown. In the present investigation, thirty-one cognitively healthy older adults underwent two different multifocal real transcranial direct current stimulation (tDCS) conditions (C1 and C2) and a sham condition in a crossover design during a rs-fMRI acquisition. The real tDCS conditions were designed to electrically induce two distinct complex neural patterns, either targeting generalized frontoparietal cortical overactivity (C1) or a detachment between the frontal areas and the posteromedial cortex (C2). Data revealed that the two tDCS conditions modulated rs-fMRI differently. C1 increased the coactivation of multiple functional couplings as compared to sham, while a smaller number of connections increased in C1 as compared to C2. At the group level, C1-induced changes were topographically consistent with the calculated electric current density distribution. At the individual level, the extent of tDCS-induced rs-fMRI modulation in C1 was related with the magnitude of the simulated electric current density estimates. These results highlight that multifocal tDCS procedures can effectively change rs-fMRI neural functioning in advancing age, being the induced modulation consistent with the spatial distribution of the simulated electric current on the brain. Moreover, our data supports that individually tailoring NIBS-based interventions grounded on subject-specific structural data might be crucial to increase tDCS potential in future studies amongst older adults.

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Spinal cord direct current stimulation: finite element analysis of the electric field and current density

Medical & Biological Engineering & Computing ◽

10.1007/s11517-011-0756-9 ◽

2011 ◽

Vol 49 (4) ◽

pp. 417-429 ◽

Cited By ~ 36

Author(s):

Gabriel R. Hernández-Labrado ◽

José L. Polo ◽

Elisa López-Dolado ◽

Jorge E. Collazos-Castro

Keyword(s):

Spinal Cord ◽

Finite Element Analysis ◽

Finite Element ◽

Electric Field ◽

Direct Current ◽

Current Density ◽

Element Analysis ◽

Direct Current Stimulation

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Role of human variability on the estimation of the electric field and of the current density during transcranial direct current stimulation

International Symposium on Electromagnetic Compatibility - EMC EUROPE ◽

10.1109/emceurope.2012.6396801 ◽

2012 ◽

Cited By ~ 1

Author(s):

M. Parazzini ◽

E. Rossi ◽

S. Fiocchi ◽

I. Liorni ◽

L. Rossi ◽

...

Keyword(s):

Electric Field ◽

Direct Current ◽

Current Density ◽

Transcranial Direct Current Stimulation ◽

Direct Current Stimulation

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Transspinal direct current stimulation immediately modifies motor cortex sensorimotor maps

Journal of Neurophysiology ◽

10.1152/jn.00784.2014 ◽

2015 ◽

Vol 113 (7) ◽

pp. 2801-2811 ◽

Cited By ~ 32

Author(s):

Weiguo Song ◽

Dennis Q. Truong ◽

Marom Bikson ◽

John H. Martin

Keyword(s):

Finite Element ◽

Motor Cortex ◽

Direct Current ◽

Current Density ◽

H Reflex ◽

Cervical Cord ◽

Sensory Response ◽

Motor Representation ◽

Direct Current Stimulation ◽

Sensory Evoked

Motor cortex (MCX) motor representation reorganization occurs after injury, learning, and different long-term stimulation paradigms. The neuromodulatory approach of transspinal direct current stimulation (tsDCS) has been used to promote evoked cortical motor responses. In the present study, we used cathodal tsDCS (c-tsDCS) of the rat cervical cord to determine if spinal cord activation can modify the MCX forelimb motor map. We used a finite-element method model based on coregistered high-resolution rat MRI and microcomputed tomography imaging data to predict spinal current density to target stimulation to the caudal cervical enlargement. We examined the effects of cathodal and anodal tsDCS on the H-reflex and c-tsDCS on responses evoked by intracortical microstimulation (ICMS). To determine if cervical c-tsDCS also modified MCX somatic sensory processing, we examined sensory evoked potentials (SEPs) produced by wrist electrical stimulation and induced changes in ongoing activity. Cervical c-tsDCS enhanced the H-reflex, and anodal depressed the H-reflex. Using cathodal stimulation to examine cortical effects, we found that cervical c-tsDCS immediately modified the forelimb MCX motor map, with decreased thresholds and an expanded area. c-tsDCS also increased SEP amplitude in the MCX. The magnitude of changes produced by c-tsDCS were greater on the motor than sensory response. Cervical c-tsDCS more strongly enhanced forelimb than hindlimb motor representation and had no effect on vibrissal representation. The finite-element model indicated current density localized to caudal cervical segments, informing forelimb motor selectivity. Our results suggest that c-tsDCS augments spinal excitability in a spatially selective manner and may improve voluntary motor function through MCX representational plasticity.

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