Significant group-level hotspots found in deep brain regions during transcranial direct current stimulation (tDCS): A computational analysis of electric fields

et al. 2021

Sci Rep

Two challenges to optimizing transcranial direct current stimulation (tDCS) are selecting between, often similar, electrode montages and accounting for inter-individual differences in response. These two factors are related by how tDCS montage determines current flow through the brain considered across or within individuals. MRI-based computational head models (CHMs) predict how brain anatomy determines electric field (EF) patterns for a given tDCS montage. Because conventional tDCS produces diffuse brain current flow, stimulation outcomes may be understood as modulation of global networks. Therefore, we developed a network-led, rather than region-led, approach. We specifically considered two common “frontal” tDCS montages that nominally target the dorsolateral prefrontal cortex; asymmetric “unilateral” (anode/cathode: F4/Fp1) and symmetric “bilateral” (F4/F3) electrode montages. CHMs of 66 participants were constructed. We showed that cathode location significantly affects EFs in the limbic network. Furthermore, using a finer parcellation of large-scale networks, we found significant differences in some of the main nodes within a network, even if there is no difference at the network level. This study generally demonstrates a methodology for considering the components of large-scale networks in CHMs instead of targeting a single region and specifically provides insight into how symmetric vs asymmetric frontal tDCS may differentially modulate networks across a population.

Section: Discussionsupporting

confidence: 86%

Group and individual level variations between symmetric and asymmetric DLPFC montages for tDCS over large scale brain network nodes

Soleimani

Saviz

et al. 2021

Sci Rep

“…Within the network nodes, frontal-operculum-insula nodes in the ventral attention network, orbitofrontal cortex and temporal pole in the limbic system, and DLPFC node in the executive control network significantly receive higher EFs by F4-Fp1 arrangement. [18,32,38,48]. Individualized head models for a group of subjects with surface-based registration to standard template allowed us to use standard functional atlas parcellation for network-level analysis of the head models.…”

Section: Discussionmentioning

confidence: 99%

“…Despite the effectiveness of tDCS, one major limitation is inter-individual differences in response [12][13][14]. The intensity and distribution current flow through the brain, reflected in the electric field (EF) magnitude across the brain, is one main reason hypothesized for the individual variations [15][16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Group and Individual Level Variations between Symmetric and Asymmetric DLPFC Montages for tDCS over Large Scale Brain Network Nodes

Soleimani¹,

Saviz²,

et al. 2020

Preprint

Two challenges to optimizing transcranial direct current stimulation (tDCS) are selecting between, often similar, electrode montages and accounting for inter-individual differences in response. These two factors are related by how tDCS montage determines current flow through the brain considered across or within individuals. MRI-based computational head models (CHMs) predict how brain anatomy determine electric field (EF) patterns for a given tDCS montage. Because conventional tDCS produces diffuse brain current flow, stimulation outcomes may be understood as modulation of global networks. Therefore, we developed network-led, rather than region-led, approach. We specifically considered two common frontal tDCS montages that nominally target the dorsolateral prefrontal cortex; asymmetric unilateral (anode/cathode: F4/Fp1) and symmetric bilateral (F4/F3) electrode montages. CHMs of 66 participants were constructed. We showed that cathode location significantly affects EFs in the limbic network. Furthermore, using a finer parcellation of large-scale networks, we found significant differences in some of main nodes within a network, even if there is no difference at the network level. This study generally demonstrates a methodology for considering the components of large-scale networks in CHMs instead of targeting a single region and specifically provides insight into how symmetric vs asymmetric frontal tDCS may differentially modulate networks across a population.

“…Deep brainstem and forebrain regions mediate the immune response throughout the body and can be potential targets for non-invasive neuromodulatory approaches. While it is impractical to activate deep regions selectivity (e.g., without activating superficial cerebral cortex) using tES, deep brain regions can certainly be reached by the electrical current (Dasilva et al, 2012;Huang et al, 2017;Gomez-Tames et al, 2020;Huang and Zhao, 2020) as well as through axonal connections between cortical activated areas (Bestmann et al, 2005;Bestmann and Feredoes, 2013). The cortical regions conventionally targeted with tES, such as frontal (Iseger et al, 2020) and temporal regions (Montenegro et al, 2011), can be used to influence the systemic immune response and prevent neuroinflammation (Dantzer, 2018).…”

Section: Introductionmentioning

confidence: 99%

Update on the Use of Transcranial Electrical Brain Stimulation to Manage Acute and Chronic COVID-19 Symptoms

Pilloni

Badran

et al. 2020

Front. Hum. Neurosci.

The coronavirus disease 19 (COVID-19) pandemic has resulted in the urgent need to develop and deploy treatment approaches that can minimize mortality and morbidity. As infection, resulting illness, and the often prolonged recovery period continue to be characterized, therapeutic roles for transcranial electrical stimulation (tES) have emerged as promising non-pharmacological interventions. tES techniques have established therapeutic potential for managing a range of conditions relevant to COVID-19 illness and recovery, and may further be relevant for the general management of increased mental health problems during this time. Furthermore, these tES techniques can be inexpensive, portable, and allow for trained self-administration. Here, we summarize the rationale for using tES techniques, specifically transcranial Direct Current Stimulation (tDCS), across the COVID-19 clinical course, and index ongoing efforts to evaluate the inclusion of tES optimal clinical care.