Factors Influencing Current Flow Through the Skin during Transcranial Electrical Stimulation: Role of Waveform, Tissue Properties, and Macro-Pores

2017 ◽  
Vol 10 (1) ◽  
pp. e16
Author(s):  
Niranjan Khadka ◽  
Ole Seibt ◽  
Vaishali Patel ◽  
Chris Thomas ◽  
Albert Mokrejs ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Current Flow ◽  
Transcranial Electrical Stimulation ◽  
Tissue Properties ◽  
Factors Influencing ◽  
Flow Through

scholarly journals A Future of Current Flow Modelling for Transcranial Electrical Stimulation?

2021 ◽  
Author(s):  
J. S. A. Lee ◽  
S. Bestmann ◽  
C. Evans
Keyword(s):  
Electrical Stimulation ◽  
Current Flow ◽  
Brain Activity ◽  
Cost Effective ◽  
Electrical Current ◽  
Transcranial Electrical Stimulation ◽  
Concentric Spheres ◽  
Mri Scans ◽  
Dose Control ◽  
Health And Disease

Abstract Purpose of Review Transcranial electrical stimulation (tES) is used to non-invasively modulate brain activity in health and disease. Current flow modeling (CFM) provides estimates of where and how much electrical current is delivered to in the brain during tES. It therefore holds promise as a method to reduce commonplace variability in tES delivery and, in turn, the outcomes of stimulation. However, the adoption of CFM has not yet been widespread and its impact on tES outcome variability is unclear. Here, we discuss the potential barriers to effective, practical CFM-informed tES use. Recent Findings CFM has progressed from models based on concentric spheres to gyri-precise head models derived from individual MRI scans. Users can now estimate the intensity of electrical fields (E-fields), their spatial extent, and the direction of current flow in a target brain region during tES. Here. we consider the multi-dimensional challenge of implementing CFM to optimise stimulation dose: this requires informed decisions to prioritise E-field characteristics most likely to result in desired stimulation outcomes, though the physiological consequences of the modelled current flow are often unknown. Second, we address the issue of a disconnect between predictions of E-field characteristics provided by CFMs and predictions of the physiological consequences of stimulation which CFMs are not designed to address. Third, we discuss how ongoing development of CFM in conjunction with other modelling approaches could overcome these challenges while maintaining accessibility for widespread use. Summary The increasing complexity and sophistication of CFM is a mandatory step towards dose control and precise, individualised delivery of tES. However, it also risks counteracting the appeal of tES as a straightforward, cost-effective tool for neuromodulation, particularly in clinical settings.

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.

Electrical stimulation of the liver cell: activation of glycogenolysis

1981 ◽  
Vol 240 (3) ◽  
pp. E226-E232
Author(s):  
K. A. Freude ◽  
L. S. Sandler ◽  
F. J. Zieve
Keyword(s):  
Electrical Stimulation ◽  
Metabolic Regulation ◽  
Glycogen Phosphorylase ◽  
Cell Activation ◽  
Current Flow ◽  
Glycogen Synthase ◽  
Rat Hepatocytes ◽  
Glycogen Metabolism ◽  
Liver Glycogen

To examine the role of ionic factors in the regulation of glycogen metabolism, we examined the effects of electrical stimulation on liver glycogen cycle enzymes. Passage of electric current through a suspension of rat hepatocytes caused the conversion of glycogen phosphorylase to its active (a) form and the simultaneous conversion of glycogen synthase to its inactive (D) form. The rise in phosphorylase a activity was dependent on the magnitude of current flow, was detectable after 5 s of current flow, and was rapidly reversible on cessation of stimulation. The activation of phosphorylase by shocking was completely eliminated by depletion of cellular Ca2+ and was restored by readdition of Ca2+. Cyclic AMP and cyclic GMP levels were unaffected by shocking. It is concluded that shocking, in the absence of any hormone or exogenous chemical, causes an increase in cytosol Ca2+, which in turn leads to activation of phosphorylase and inactivation of synthase. Electrical stimulation may serve as a model system for studying the role of ions in metabolic regulation.

scholarly journals Toward integrative approaches to study the causal role of neural oscillations via transcranial electrical stimulation

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Valeriia Beliaeva ◽  
Iurii Savvateev ◽  
Valerio Zerbi ◽  
Rafael Polania
Keyword(s):  
Electrical Stimulation ◽  
Causal Role ◽  
Neural Oscillations ◽  
Transcranial Electrical Stimulation ◽  
Integrative Research ◽  
Critical Issues ◽  
Neural Entrainment ◽  
Approaches To Study ◽  
Translational Approach

AbstractDiverse transcranial electrical stimulation (tES) techniques have recently been developed to elucidate the role of neural oscillations, but critically, it remains questionable whether neural entrainment genuinely occurs and is causally related to the resulting behavior. Here, we provide a perspective on an emerging integrative research program across systems, species, theoretical and experimental frameworks to elucidate the potential of tES to induce neural entrainment. We argue that such an integrative agenda is a requirement to establish tES as a tool to test the causal role of neural oscillations and highlight critical issues that should be considered when adopting a translational approach.

scholarly journals A future of current flow modelling for transcranial electrical stimulation?

2021 ◽  
Author(s):  
Jenny lee ◽  
Sven Bestmann ◽  
Carys Evans
Keyword(s):  
Electrical Stimulation ◽  
Current Flow ◽  
Brain Activity ◽  
Cost Effective ◽  
Electrical Current ◽  
Transcranial Electrical Stimulation ◽  
Clinical Settings ◽  
Dose Control ◽  
Health And Disease ◽  
The Brain

Transcranial electrical stimulation (tES) is used to non-invasively modulate brain activity in health and disease. Current flow modeling (CFM) provides estimates of where, and how much electrical current is delivered to the brain during tES. It therefore holds promise as a method to reduce commonplace variability in tES delivery and, in turn, the outcomes of stimulation. However, the adoption of CFM has not yet been widespread and its impact on tES outcome variability is unclear. Here we discuss the potential barriers to effective, practical CFM-informed tES use. We first consider the multi-dimensional challenge of optimising stimulation dose. CFMs estimate the intensity of electrical fields (E-fields), their spatial extent, and the direction of current flow in a target brain region during tES. Researchers must make informed decisions to prioritise E-field characteristics most likely to result in desired stimulation outcomes, though the physiological consequences of the modelled current flow are often unknown. Second, we address the issue of a disconnect between predictions of E-field characteristics provided by CFMs, and predictions of the physiological consequences of stimulation which CFMs are not designed to address. Third, we discuss how ongoing development of CFM in conjunction with other modelling approaches could overcome these challenges while maintaining accessibility for widespread use. The increasing complexity and sophistication of CFM is a mandatory step towards dose control and precise, individualised delivery of tES, but also risks counteracting the appeal of tES as a straight-forward, cost effective tool for neuromodulation, particularly in clinical settings.

Transcranial Electrical Stimulation in Post-Stroke Cognitive Rehabilitation

2016 ◽  
Vol 21 (1) ◽  
pp. 55-64 ◽  
Author(s):  
Silvia Convento ◽  
Cristina Russo ◽  
Luca Zigiotto ◽  
Nadia Bolognini
Keyword(s):  
Electrical Stimulation ◽  
Cognitive Rehabilitation ◽  
Cognitive Disorders ◽  
Spatial Neglect ◽  
Transcranial Electrical Stimulation ◽  
Clinical Settings ◽  
Post Stroke ◽  
Neuropsychological Disorders ◽  
Current State ◽  
Stimulation Technique

Abstract. Cognitive rehabilitation is an important area of neurological rehabilitation, which aims at the treatment of cognitive disorders due to acquired brain damage of different etiology, including stroke. Although the importance of cognitive rehabilitation for stroke survivors is well recognized, available cognitive treatments for neuropsychological disorders, such as spatial neglect, hemianopia, apraxia, and working memory, are overall still unsatisfactory. The growing body of evidence supporting the potential of the transcranial Electrical Stimulation (tES) as tool for interacting with neuroplasticity in the human brain, in turn for enhancing perceptual and cognitive functions, has obvious implications for the translation of this noninvasive brain stimulation technique into clinical settings, in particular for the development of tES as adjuvant tool for cognitive rehabilitation. The present review aims at presenting the current state of art concerning the use of tES for the improvement of post-stroke visual and cognitive deficits (except for aphasia and memory disorders), showing the therapeutic promises of this technique and offering some suggestions for the design of future clinical trials. Although this line of research is still in infancy, as compared to the progresses made in the last years in other neurorehabilitation domains, current findings appear very encouraging, supporting the development of tES for the treatment of post-stroke cognitive impairments.

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