Modeling sequence and quasi-uniform assumption in computational neurostimulation

Bikson, Marom; Truong, Dennis Q.; Mourdoukoutas, Antonios P.; Aboseria, Mohamed; Khadka, Niranjan; Adair, Devin; Rahman, Asif

doi:10.1016/bs.pbr.2015.08.005

Cited by 54 publications

(48 citation statements)

References 124 publications

(135 reference statements)

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“…Conductivity value for each tissue mask was based on prior literature (Bikson et al, 2015). Electrodes for uni-hemisphere montage (35/100 cm 2 scalp contact area) and bi-hemisphere montage (35/35 cm 2 scalp contact area) positioned over IFG (Fig.…”

Section: Methodsmentioning

confidence: 99%

The differential effects of unihemispheric and bihemispheric tDCS over the inferior frontal gyrus on proactive control

Leite

Gonçalves

Pereira

et al. 2018

Neuroscience Research

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This study examined the effects of bihemispheric and unihemispheric transcranial Direct Current Stimulation (tDCS) over the inferior frontal gyrus (IFG) on proactive control. Sixteen participants were randomized to receive (i) bihemispheric tDCS, with a 35 cm2 anodal electrode of the right IFG and a 35 cm2 cathode electrode of left IFG or (ii) unihemispheric tDCS, with a 35 cm2 anodal electrode of the right IFG and a 100 cm2 electrode of the left IFG or (iii) sham tDCS, while performing a prepotent inhibition task. There were significant speed-accuracy tradeoff effects in terms of switch costs: unihemispheric tDCS significantly decreased the accuracy when compared to bihemispheric, and sham tDCS, while increased response time when comparing to bihemispheric and sham tDCS. The computational model showed a symmetrical field intensity for the bihemispheric tDCS montage, and an asymmetrical for the unihemispheric tDCS montage. This study confirms that unihemispheric tDCS over the rIFG has a significant impact on response inhibition. The lack of results of bihemispheric tDCS brings two important findings for this study: (i) left IFG seems to be also critically associated with inhibitory response control, and (ii) these results highlight the importance of considering the dual effects of tDCS when choosing the electrode montage.

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Section: Methodsmentioning

confidence: 99%

The differential effects of unihemispheric and bihemispheric tDCS over the inferior frontal gyrus on proactive control

Leite

Gonçalves

Pereira

et al. 2018

Neuroscience Research

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“…We feel increased emphasis on translational animal studies that increase clinical relevance, and recognition in the clinical space that more sophisticated strategies are needed, may correct this trend. Central to enhancing the sophistication of tDCS, including leveraging animal studies, is the notion of “computational neurostimulation” where interventional strategies are informed by quantitative models (Bestmann, 2015, Bikson et al, 2015, Rahman et al, 2015). …”

Section: Summary: 3 Tier Approach Beyond the Somatic Doctrine Exmentioning

confidence: 99%

Animal models of transcranial direct current stimulation: Methods and mechanisms

Jackson

Rahman

Lafon

et al. 2016

Clinical Neurophysiology

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The objective of this review is to summarize the contribution of animal research using direct current stimulation (DCS) to our understanding of the physiological effects of transcranial direct current stimulation (tDCS). We comprehensively address experimental methodology in animal studies, broadly classified as: 1) transcranial stimulation; 2) direct cortical stimulation in vivo and 3) in vitro models. In each case advantages and disadvantages for translational research are discussed including dose translation and the overarching “quasi-uniform” assumption, which underpins translational relevance in all animal models of tDCS. Terminology such as anode, cathode, inward current, outward current, current density, electric field, and uniform are defined. Though we put key animal experiments spanning decades in perspective, our goal is not simply an exhaustive cataloging of relevant animal studies, but rather to put them in context of ongoing efforts to improve tDCS. Cellular targets, including excitatory neuronal somas, dendrites, axons, interneurons, glial cells, and endothelial cells are considered. We emphasize neurons are always depolarized and hyperpolarized such that effects of DCS on neuronal excitability can only be evaluated within subcellular regions of the neuron. Findings from animal studies on the effects of DCS on plasticity (LTP/LTD) and network oscillations are reviewed extensively. Any endogenous phenomena dependent on membrane potential changes are, in theory, susceptible to modulation by DCS. The relevance of morphological changes (galvanotropy) to tDCS is also considered, as we suggest microscopic migration of axon terminals or dendritic spines may be relevant during tDCS. A majority of clinical studies using tDCS employ a simplistic dose strategy where excitability is singularly increased or decreased under the anode and cathode, respectively. We discuss how this strategy, itself based on classic animal studies, cannot account for the complexity of normal and pathological brain function, and how recent studies have already indicated more sophisticated approaches are necessary. One tDCS theory regarding “functional targeting” suggests the specificity of tDCS effects are possible by modulating ongoing function (plasticity). Use of animal models of disease are summarized including pain, movement disorders, stroke, and epilepsy.

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“…We will also introduce more recent NIBS approaches like transcranial alternating current stimulation (tACS) and transcranial random noise stimulation (tRNS). With respect to the application of these techniques, the emerging field of computational neurostimulation [5] might substantially advance the experimental and clinical use of NIBS by establishing quantitative models that link stimulation dose to behavioural and clinical outcomes and provide insight into the physiological underpinnings of the stimulation effects [6]. …”

Section: An Introduction To the Study Of Language Networkmentioning

confidence: 99%

“…It is generally assumed that the strongest tDCS effect should occur at the stimulated area under the electrode [52], but functional effects also engage distant neural networks [53], and the position of the second electrode probably affects the effects under the first one [54]. Common montages place both electrodes on the head in a bipolar arrangement, although in theory, the reference electrode can be placed anywhere on the body to ensure that it exerts no physiological effects of its own [6]. Given the overall low focality of tDCS, a direct structure-function relationship is hard to establish, especially with respect to the induced behavioral changes [55].…”

Section: An Introduction To Noninvasive Brain Stimulationmentioning

confidence: 99%

Adaptive Plasticity in the Healthy Language Network: Implications for Language Recovery after Stroke

Hartwigsen

2016

Neural Plasticity

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Across the last three decades, the application of noninvasive brain stimulation (NIBS) has substantially increased the current knowledge of the brain's potential to undergo rapid short-term reorganization on the systems level. A large number of studies applied transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) in the healthy brain to probe the functional relevance and interaction of specific areas for different cognitive processes. NIBS is also increasingly being used to induce adaptive plasticity in motor and cognitive networks and shape cognitive functions. Recently, NIBS has been combined with electrophysiological techniques to modulate neural oscillations of specific cortical networks. In this review, we will discuss recent advances in the use of NIBS to modulate neural activity and effective connectivity in the healthy language network, with a special focus on the combination of NIBS and neuroimaging or electrophysiological approaches. Moreover, we outline how these results can be transferred to the lesioned brain to unravel the dynamics of reorganization processes in poststroke aphasia. We conclude with a critical discussion on the potential of NIBS to facilitate language recovery after stroke and propose a phase-specific model for the application of NIBS in language rehabilitation.

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Modeling sequence and quasi-uniform assumption in computational neurostimulation

Cited by 54 publications

References 124 publications

The differential effects of unihemispheric and bihemispheric tDCS over the inferior frontal gyrus on proactive control

The differential effects of unihemispheric and bihemispheric tDCS over the inferior frontal gyrus on proactive control

Animal models of transcranial direct current stimulation: Methods and mechanisms

Adaptive Plasticity in the Healthy Language Network: Implications for Language Recovery after Stroke

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