scholarly journals Intracranial Electric Field Recording During Multichannel Transcranial Electrical Stimulation

2021 ◽  
Author(s):  
Minmin Wang ◽  
Jiawei Han ◽  
Hongjie Jiang ◽  
Junming Zhu ◽  
Wuwei Feng ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Simulation Model ◽  
Electric Fields ◽  
Simulation Models ◽  
Transcranial Electrical Stimulation ◽  
Induced Voltage ◽  
Linear Superposition ◽  
In Vivo Measurements ◽  
Highly Correlated

Background: Multichannel transcranial electrical stimulation (tES) modeling and optimization have been widely studied in recent years. Its theoretical bases include quasi-static assumption and linear superposition. However, there is still a lack of direct in vivo evidence to validate the simulation model and theoretical assumptions. Methods: We directly measured the multichannel tES-induced voltage changes with implanted stereotactic-electroencephalographic (sEEG) electrodes in 12 epilepsy subjects. By combining these measured data, we investigate the linear superposition and prediction accuracy of simulation models for multi-electrode stimulation and further compare the induced EF differences between transcranial direct current stimulation (tDCS) and transcranial alternating current stimulation (tACS). Results: Our in vivo measurements demonstrated that the multi-electrode tES-induced voltages were almost equal to the sum of the voltages generated independently by bipolar stimulation. Both measured voltages and electric fields obtained in vivo were highly correlated with the predicted values in our cohort (Voltages: r = 0.92, p < 0.001; electric fields: r = 0.74, p < 0.001). Under the same stimulation intensity, the tDCS-induced peak-zero voltages were highly correlated with the values of tACS (r = 0.99, p < 0.001; s = 0.99). Conclusions: The in vivo measurements provides confirmatory results for linear superposition and quasi-static assumption within the human brain. Furthermore, we found that the individualized simulation model reliably predicted the multi-electrode tES-induced electric fields.

Role of BKCa Channels in Cephalic Vasodilation Induced by CGRP, NO and Transcranial Electrical Stimulation In The Rat

Cephalalgia ◽  
2007 ◽  
Vol 27 (10) ◽  
pp. 1120-1127 ◽  
Author(s):  
A Gozalov ◽  
I Jansen-Olesen ◽  
D Klaerke ◽  
J Olesen
Keyword(s):  
Nitric Oxide ◽  
Electrical Stimulation ◽  
Selective Inhibitor ◽  
Transcranial Electrical Stimulation ◽  
Bkca Channels ◽  
No Donor ◽  
Calcitonin Gene

Both calcitonin gene-related peptide (CGRP) and nitric oxide (NO) are potent vasodilators that have been shown to induce headache in migraine patients. Their antagonists are effective in the treatment of migraine attacks. In the present study, we hypothesize that vasodilation induced by the NO donor glyceryltrinitrate (GTN) or by CGRP is partially mediated via large conductance calcium-activated potassium (BKCa) channels. The effects of the BKCa channel selective inhibitor iberiotoxin on dural and pial vasodilation induced by CGRP, GTN and endogenously released CGRP by transcranial electrical stimulation (TES) were examined. Iberiotoxin significantly attenuated GTN-induced dural and pial artery dilation in vivo and in vitro, but had no effect on vasodilation induced by CGRP and TES. Our results show that GTN- but not CGRP-induced dural and pial vasodilation involves opening of BKCa channels in rat.

O-48 Interictal discharges neuromodulation using transcranial electrical stimulation : a simultaneous tDCS-SEEG study in human in vivo

2019 ◽  
Vol 130 (7) ◽  
pp. e36-e37
Author(s):  
Samuel Louviot ◽  
Jacek Dmochowski ◽  
Louise Tyvaert ◽  
Sophie Colnat-Coulbois ◽  
Louis Maillard ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Transcranial Electrical Stimulation ◽  
Interictal Discharges

scholarly journals Inter-individual and age-dependent variability in simulated electric fields induced by conventional transcranial electrical stimulation

NeuroImage ◽  
2021 ◽  
Vol 224 ◽  
pp. 117413
Author(s):  
Daria Antonenko ◽  
Ulrike Grittner ◽  
Guilherme Saturnino ◽  
Till Nierhaus ◽  
Axel Thielscher ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Electric Fields ◽  
Transcranial Electrical Stimulation ◽  
Age Dependent

scholarly journals Electrical neuromodulation biases brightness perception of flickering light

2021 ◽  
Author(s):  
Marina Fiene ◽  
Jan-Ole Radecke ◽  
Jonas Misselhorn ◽  
Malte Sengelmann ◽  
Christoph S. Herrmann ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Electric Fields ◽  
Subjective Experience ◽  
Phase Synchronization ◽  
Temporal Dynamics ◽  
Cortical Excitability ◽  
Brightness Discrimination ◽  
Transcranial Electrical Stimulation ◽  
Subjective Perception ◽  
Brightness Perception

Human brightness estimation often pronouncedly dissociates from objective viewing conditions. Yet, the physiological substrate underlying subjective perception is still poorly understood. Rather than physical illumination, the subjective experience of brightness has been shown to correlate with temporal dynamics in the amplitude of cortical neural responses. Here, we aimed to experimentally manipulate visual flicker-evoked steady-state responses and related perception via concurrent modulation of cortical excitability by transcranial alternating current stimulation. Participants performed a brightness discrimination task of two visual flicker stimuli, one of which was targeted by same-frequency electrical stimulation at varying phase shifts. Transcranial electrical stimulation was applied with an occipital and a periorbital active control montage, based on finite-element method simulations of electric fields. Experimental results reveal that flicker brightness perception is modulated dependent on the phase shift between sensory and electrical stimulation, solely under stable flicker entrainment and exclusively under occipital electrical stimulation. The degree of induced brightness modulation was positively correlated with the strength of neuronal phase locking to the flicker, recorded prior to electrical stimulation. This finding was corroborated by a neural network model, demonstrating a comparable dependency between flicker-evoked phase synchronization and amplitude modulations of entrained neural rhythms by phase shifted visual and electric inputs. Our data suggest a causal role of the amplitude of neural activity in visual cortex for brightness perception in humans. This finding provides an important step towards understanding the basis of visual perception and further confirms electrical stimulation as a tool for advancing controlled modulations of neural excitability and related behavior.

scholarly journals Promoting osseointegration with electrical stimulation: a review

2021 ◽  
Author(s):  
Emily Pettersen ◽  
Jenna Anderson ◽  
Max Ortiz-Catalan
Keyword(s):  
Electrical Stimulation ◽  
Electric Fields ◽  
Meta Analysis ◽  
Implant Surface ◽  
Power Sources ◽  
Stimulation Parameters ◽  
Bone Quantity ◽  
Major Factors

<p>Electrical stimulation has shown to be a promising approach for promoting osseointegration in bone-anchored implants, where osseointegration defines the biological bonding between an implant surface and bone tissue. Bone-anchored implants are used in the rehabilitation of hearing and limb loss, and extensively in edentulous patients. Inadequate osseointegration is one of the major factors of implant failure that could be prevented by accelerating or enhancing the osseointegration process by artificial means. In this article, we reviewed the efforts to enhance the biofunctionality at the implant-bone interface with electrical stimulation using various approaches such as different electrode configurations, power sources, and waveform-dependent stimulation parameters tested in different <i>in vitro</i> and <i>in vivo</i> models. We reviewed and compared studies from the last 45 years and found nonuniform protocols with disparities in cell type and animal model, implant location, experimental timeline, implant material, evaluation assays, and type of electrical stimulation. The reporting of stimulation parameters was also found to be inconsistent and incomplete throughout the literature. Studies using <i>in vitro</i> models showed that osteoblasts were sensitive to the magnitude of the electric field and duration of exposure, and such variables similarly affected bone quantity around implants in <i>in vivo </i>investigations. Most studies showed benefits of electrical stimulation in the underlying processes leading to osseointegration, and therefore we found the idea of promoting osseointegration by using electric fields to be supported by the available evidence. However, such an effect has not been demonstrated conclusively nor optimally in humans. We found that optimal stimulation parameters have not been thoroughly investigated and this remains an important step towards the clinical translation of this concept. In addition, there is a need for reporting standards to enable meta-analysis for evidence-based treatments.</p>

scholarly journals Transcranial Electrical Stimulation generates electric fields in deep human brain structures

2021 ◽  
Author(s):  
Samuel Louviot ◽  
Louise Tyvaert ◽  
Louis G. Maillard ◽  
Sophie Colnat-Coulbois ◽  
Jacek Dmochowski ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Human Brain ◽  
Electric Fields ◽  
Brain Structures ◽  
Transcranial Electrical Stimulation

scholarly journals Modeling implanted metals in electrical stimulation applications

2021 ◽  
Author(s):  
Borja Mercadal ◽  
Ricardo Salvador ◽  
Maria Chiara Biagi ◽  
Fabrice Bartolomei ◽  
Fabrice Wendling ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Electric Fields ◽  
Strong Field ◽  
Numerical Models ◽  
The Body ◽  
Transcranial Electrical Stimulation ◽  
Head Model ◽  
Perfect Conductor ◽  
Theoretical Argument ◽  
Metal Implants

AbstractBackgroundMetal implants impact the dosimetry assessment in electrical stimulation techniques. Therefore, they need to be included in numerical models. While currents in the body are ionic, metals only allow electron transport. In fact, charge transfer between tissues and metals requires electric fields to drive the electrochemical reactions at the interface. Thus, metal implants may act as insulators or as conductors depending on the scenario.Objective/HypothesisThe aim of this paper is to provide a theoretical argument that guides the choice of the correct representation of metal implants using purely electrical models but considering the electrochemical nature of the problem in the technology of interest.MethodsWe built a simple model of a metal implant exposed to a homogeneous electric field of various magnitudes to represent both weak (e.g., tDCS), medium (TMS) or strong field stimulation. The same geometry was solved using two different models: a purely electric one (with different conductivities for the implant), and an electrochemical one. As an example of application, we also modeled a transcranial electrical stimulation (tES) treatment in a realistic head model with a skull plate using a high and low conductivity value for the plate.ResultsMetal implants generally act as electric insulators when exposed to electric fields up to around 100 V/m (tES and TMS range) and they only resemble a perfect conductor for fields in the order of 1000 V/m and above. The results are independent of the implant’s metal, but they depend on its geometry.Conclusion(s)Metal implants can be accurately represented by a simple electrical model of constant conductivity, but an incorrect model choice can lead to large errors in the dosimetry assessment. In particular, tES modeling with implants incorrectly treated as conductors can lead to errors of 50% in induced fields or more. Our results can be used as a guide to select the correct model in each scenario.

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