scholarly journals Electric Field Dynamics in the Brain During Multi-Electrode Transcranial Electric Stimulation

2018 ◽  
Author(s):  
Ivan Alekseichuk ◽  
Arnaud Y. Falchier ◽  
Gary Linn ◽  
Ting Xu ◽  
Michael P. Milham ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Stimulation ◽  
Brain Regions ◽  
Neural Oscillations ◽  
Non Invasive ◽  
Multiple Electrodes ◽  
Transcranial Electric Stimulation ◽  
Mechanistic Understanding ◽  
Linear Manner ◽  
The Brain

ABSTRACTNeural oscillations play a crucial role in communication between remote brain areas. Transcranial electric stimulation with alternating currents (TACS) can manipulate these brain oscillations in a non-invasive manner. Of particular interest, TACS protocols using multiple electrodes with phase shifted stimulation currents were developed to alter the connectivity between two or more brain regions. Typically, an increase in coordination between two sites is assumed when they experience an in-phase stimulation and a disorganization through an anti-phase stimulation. However, the underlying biophysics of multi-electrode TACS has not been studied in detail, thus limiting our ability to develop a mechanistic understanding. Here, we leverage direct invasive recordings from two non-human primates during multi-electrode TACS to show that the electric field magnitude and phase depend on the phase of the stimulation currents in a non-linear manner. Further, we report a novel phenomenon of a “traveling wave” stimulation where the location of the electric field maximum changes over the stimulation cycle. Our results provide a basis for a mechanistic understanding of multi-electrode TACS, necessitating the reevaluation of previously published studies, and enable future developments of novel stimulation protocols.

scholarly journals Spatiotemporal structure of intracranial electric fields induced by transcranial electric stimulation in human and nonhuman primates

2016 ◽  
Author(s):  
Alexander Opitz ◽  
Arnaud Falchier ◽  
Chao-Gan Yan ◽  
Erin Yeagle ◽  
Gary Linn ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Electric Stimulation ◽  
Brain Regions ◽  
Electrode Arrays ◽  
Non Invasive ◽  
Crucial Information ◽  
Cebus Monkeys ◽  
Transcranial Electric Stimulation ◽  
The Brain

AbstractTranscranial electric stimulation (TES) is an emerging technique, developed to non-invasively modulate brain function. However, the spatiotemporal distribution of the intracranial electric fields induced by TES remains poorly understood. In particular, it is unclear how much current actually reaches the brain, and how it distributes across the brain. Lack of this basic information precludes a firm mechanistic understanding of TES effects. In this study we directly measure the spatial and temporal characteristics of the electric field generated by TES using stereotactic EEG (s-EEG) electrode arrays implanted in cebus monkeys and surgical epilepsy patients. We found a small frequency dependent decrease (10%) in magnitudes of TES induced potentials and negligible phase shifts over space. Electric field strengths were strongest in superficial brain regions with maximum values of about 0.5 mV/mm. Our results provide crucial information for the interpretation of human TES studies and the optimization and design of TES stimulation protocols. In addition, our findings have broad implications concerning electric field propagation in non-invasive recording techniques such as EEG/MEG.

scholarly journals Electric field dynamics in the brain during multi-electrode transcranial electric stimulation

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Ivan Alekseichuk ◽  
Arnaud Y. Falchier ◽  
Gary Linn ◽  
Ting Xu ◽  
Michael P. Milham ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Stimulation ◽  
Transcranial Electric Stimulation ◽  
The Brain

scholarly journals Can transcranial electric stimulation with multiple electrodes reach deep targets?

2018 ◽  
Author(s):  
Yu Huang ◽  
Lucas C Parra
Keyword(s):  
Electric Stimulation ◽  
Target Location ◽  
Head Model ◽  
Multiple Electrodes ◽  
Realistic Head Model ◽  
Transcranial Electric Stimulation ◽  
The Brain ◽  
Deep Target ◽  
Deep Brain ◽  
Intense Stimulation

To reach a deep target in the brain with transcranial electric stimulation (TES), currents have to pass also through the cortical surface. Thus, it is generally thought that TES cannot achieve focal deep brain stimulation. Recent efforts with interfering waveforms and pulsed stimulation have argued that one can achieve deeper or more intense stimulation in the brain. Here we argue that conventional transcranial stimulation with multiple current sources is just as effective as these new approaches. The conventional multi-electrode approach can be numerically optimized to maximize intensity or focality at a desired target location. Using such optimal electrode configurations we find in a detailed and realistic head model that deep targets may in fact be strongly stimulated, with cerebrospinal fluid guiding currents deep into the brain.

scholarly journals High spatial correlation in brain connectivity between micturition and resting states within bladder-related networks using 7 T MRI in multiple sclerosis women with voiding dysfunction

2021 ◽  
Author(s):  
Zhaoyue Shi ◽  
Khue Tran ◽  
Christof Karmonik ◽  
Timothy Boone ◽  
Rose Khavari
Keyword(s):  
Multiple Sclerosis ◽  
Resting State ◽  
Voiding Dysfunction ◽  
Brain Connectivity ◽  
Resting State Fmri ◽  
Brain Regions ◽  
Functional Magnetic Resonance ◽  
Non Invasive ◽  
Potential Alternative ◽  
The Brain

Abstract Background Several studies have reported brain activations and functional connectivity (FC) during micturition using functional magnetic resonance imaging (fMRI) and concurrent urodynamics (UDS) testing. However, due to the invasive nature of UDS procedure, non-invasive resting-state fMRI is being explored as a potential alternative. The purpose of this study is to evaluate the feasibility of utilizing resting states as a non-invasive alternative for investigating the bladder-related networks in the brain. Methods We quantitatively compared FC in brain regions belonging to the bladder-related network during the following states: ‘strong desire to void’, ‘voiding initiation (or attempt at voiding initiation)’, and ‘voiding (or continued attempt of voiding)’ with FC during rest in nine multiple sclerosis women with voiding dysfunction using fMRI data acquired at 7 T and 3 T. Results The inter-subject correlation analysis showed that voiding (or continued attempt of voiding) is achieved through similar network connections in all subjects. The task-based bladder-related network closely resembles the resting-state intrinsic network only during voiding (or continued attempt of voiding) process but not at other states. Conclusion Resting states fMRI can be potentially utilized to accurately reflect the voiding (or continued attempt of voiding) network. Concurrent UDS testing is still necessary for studying the effects of strong desire to void and initiation of voiding (or attempt at initiation of voiding).

scholarly journals Transcranial electric stimulation seen from within the brain

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Angel V Peterchev
Keyword(s):  
Electric Stimulation ◽  
Computer Models ◽  
Transcranial Electric Stimulation ◽  
The Brain

Computer models can make transcranial electric stimulation a better tool for research and therapy.

scholarly journals SimNIBS 2.1: A Comprehensive Pipeline for Individualized Electric Field Modelling for Transcranial Brain Stimulation

2018 ◽  
Author(s):  
Guilherme B. Saturnino ◽  
Oula Puonti ◽  
Jesper D Nielsen ◽  
Daria Antonenko ◽  
Kristoffer Hougaard H Madsen ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Brain Stimulation ◽  
Head Model ◽  
Non Invasive ◽  
Field Modelling ◽  
Transcranial Brain Stimulation ◽  
Automated Tools ◽  
Automated Placement ◽  
The Brain

Numerical simulation of the electric fields induced by Non-Invasive Brain Stimulation (NIBS), using realistic anatomical head models has gained interest in recent years for understanding the NIBS effects in individual subjects. Although automated tools for generating the head models and performing the electric field simulations have become available, individualized modelling is still not standard practice in NIBS studies. This is likely partly explained by the lack of robustness and usability of the previously available software tools, and partly by the still developing understanding of the link between physiological effects and electric field distributions in the brain. To facilitate individualized modelling in NIBS, we have introduced the SimNIBS (Simulation of NIBS) software package, providing easy-to-use automated tools for electric field modelling. In this article, we give an overview of the modelling pipeline in SimNIBS 2.1, with step-by-step examples of how to run a simulation. Furthermore, we demonstrate a set of scripts for extracting average electric fields for a group of subjects, and finally demonstrate the accuracy of automated placement of standard electrode montages on the head model. SimNIBS 2.1 is freely available at www.simnibs.org.

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