Anatomical and fMRI-network comparison of multiple DLPFC targeting strategies for repetitive transcranial magnetic stimulation treatment of depression

Cardenas, Valerie A.; Bhat, Jyoti; Horwege, Andrea M; Ehrlich, Tobin J.; Lavacot, James A.; Mathalon, Daniel H.; Glover, Gary H.; Roach, Brian; Badran, Bashar W.; Forman, Steven D.; George, Mark S.; Thase, Michael E.; Yesavage, Jerome A.; Yurgelun‐Todd, Deborah; Rosen, Allyson

doi:10.1016/j.brs.2021.11.008

Cited by 40 publications

(19 citation statements)

References 80 publications

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“…Using functional MRI as an example, functional connectivity-based DLPFC targeting for the treatment of major depressive disorders has been well developed and evaluated [ 23 , 34 , 35 ]. Although there were significant differences in target-based functional connectivity among DLPFC targets [ 25 , 36 , 37 ], the heterogeneity in targeting highlights the necessity and importance of pinpointing the optimal stimulation sites within the DLPFC rather than a general anatomical area. Despite these informative findings, a pertinent question is concerned with the more efficient strategy for determining the precise targets for TMS treatment or, alternatively, whether optimal targeting within a TMS target is a quick and plausible way for clinical populations, particularly those with neurodegenerative diseases.…”

Section: Discussionmentioning

confidence: 99%

Pinpointing the precise stimulation targets for brain rehabilitation in early-stage Parkinson’s disease

Zhang

et al. 2023

BMC Neurosci

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Background Transcranial magnetic stimulation (TMS) is increasingly used as a promising non-pharmacological treatment for Parkinson’s disease (PD). Scalp-to-cortex distance (SCD), as a key technical parameter of TMS, plays a critical role in determining the locations of treatment targets and corresponding dosage. Due to the discrepancies in TMS protocols, the optimal targets and head models have yet to be established in PD patients. Objective To investigate the SCDs of the most popular used targets in left dorsolateral prefrontal cortex (DLPFC) and quantify its impact on the TMS-induced electric fields (E-fields) in early-stage PD patients. Methods Structural magnetic resonance imaging scans from PD patients (n = 47) and normal controls (n = 36) were drawn from the NEUROCON and Tao Wu datasets. SCD of left DLPFC was measured by Euclidean Distance in TMS Navigation system. The intensity and focality of SCD-dependent E-fields were examined and quantified using Finite Element Method. Results Early-stage PD patients showed an increased SCDs, higher variances in the SCDs and SCD-dependent E-fields across the seven targets of left DLPFC than normal controls. The stimulation targets located on gyral crown had more focal and homogeneous E-fields. The SCD of left DLPFC had a better performance in differentiating early-stage PD patients than global cognition and other brain measures. Conclusion SCD and SCD-dependent E-fields could determine the optimal TMS treatment targets and may also be used as a novel marker to differentiate early-stage PD patients. Our findings have important implications for developing optimal TMS protocols and personalized dosimetry in real-world clinical practice.

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Section: Discussionmentioning

confidence: 99%

Pinpointing the precise stimulation targets for brain rehabilitation in early-stage Parkinson’s disease

Zhang

et al. 2023

BMC Neurosci

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“…Our computational approach with a substantial sample size underlies the utility of head models for uncovering potentially stimulated brain regions based on EF peaks. As investigated in previous brain stimulation studies [33], the efficacy of the stimulation protocol may vary depending on the brain region being modulated. However, systematic analysis of EF distribution patterns and finding the association between tES-induced EFs and stimulation outcomes requires a decision about which EF measures (e.g., maximum (99 th percentile to remove outliers), mean, median, or a binary thresholded EF map) are appropriate to use.…”

Section: Importance Of Peak Efs In Brain Stimulation Studiesmentioning

confidence: 99%

Are we really targeting and stimulating DLPFC by placing transcranial electrical stimulation (tES) electrodes over F3/F4?

Soleimani

Kuplicki

Camchong

et al. 2022

Preprint

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Background: Most transcranial electrical stimulation (tES) clinical trials place target electrodes over DLPFC based on the assumption that it would mainly stimulate the underlying brain region. Here, we assessed delivered electric fields (EF) using a symmetric and asymmetric DLPFC stimulation montage to identify additional prefrontal regions that are inadvertently targeted beyond DLPFC. Methods: Head models were generated from the human connectome project database's T1+T2-weighted MRIs of 80 healthy adults. Two common DLPFC montages (symmetric: F4/F3, asymmetric: F4/Fp1 with 5x7cm electrodes, 2mA intensity) were simulated. Averaged EF was extracted from (1) the center of the target electrode (F4), and (2) the top 1% of voxels that showed the strongest EF in individualized EF maps. Inter-individual variabilities were quantified with standard deviation (SD) of EF peak location and value. These steps were replicated with 66 participants with methamphetamine use disorder (MUD) as an independent clinical population. Results: In the healthy adults, EFs in the frontopolar area were significantly higher than EF under the target electrode in both symmetric (peak:0.41+-0.06, F4:0.22+-0.04) and asymmetric (peak:0.38+-0.04, F4:0.2+-0.04) montages (Heges g>0.7). Group-level location for EF peaks in MNI space was located in medial-frontopolar cortex, such that individualized EF peaks were placed in a cube with a volume of symmetric/asymmetric: 29cm3/46cm3. Similar results (with slight between-group differences) were found for MUDs that highlighted the role of the medial frontopolar cortex in both healthy and clinical populations. Conclusions: We highlighted that in common DLPFC tES montages, DLPFC was not maximally targeted and the frontopolar area was the area that received the highest EFs. Considering inter-individual and inter-groups variability, we specifically recommended that the frontopolar role should be considered as a potential mechanism underlying the clinical efficacy of DLPFC stimulation.

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“…Our computational approach with a substantial sample size underlies the utility of head models for uncovering potentially stimulated brain regions based on EF peaks. As investigated in previous brain stimulation studies [33], the e cacy of the stimulation protocol may vary depending on the brain region being modulated. However, systematic analysis of EF distribution patterns and nding the association between tES-induced EFs and stimulation outcomes requires a decision about which EF measures (e.g., maximum (99th percentile to remove outliers), mean, median, or a binary thresholded EF map) are appropriate to use.…”

Section: Importance Of Peak Efs In Brain Stimulation Studiesmentioning

confidence: 99%

Are we really targeting and stimulating DLPFC by placing tES electrodes over F3/F4?

Ekhtiari

Soleimani²,

Kuplicki

et al. 2022

Preprint

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Background: Most transcranial electrical stimulation (tES) clinical trials place target electrodes over DLPFC based on the assumption that it would mainly stimulate the underlying brain region. Here, we assessed delivered electric fields (EF) using a symmetric and asymmetric DLPFC stimulation montage to identify additional prefrontal regions that are inadvertently targeted beyond DLPFC. Methods: Head models were generated from the human connectome project database's T1+T2-weighted MRIs of 80 healthy adults. Two common DLPFC montages (symmetric: F4/F3, asymmetric: F4/Fp1 with 5×7cm electrodes, 2mA intensity) were simulated. Averaged EF was extracted from (1) the center of the target electrode (F4), and (2) the top 1% of voxels that showed the strongest EF in individualized EF maps. Inter-individual variabilities were quantified with standard deviation (SD) of EF peak location and value. These steps were replicated with 66 participants with methamphetamine use disorder (MUD) as an independent clinical population. Results: In the healthy adults, EFs in the frontopolar area were significantly higher than EF “under” the target electrode in both symmetric (peak:0.41±0.06, F4:0.22±0.04) and asymmetric (peak:0.38±0.04, F4:0.2±0.04) montages (Heges’g>0.7). Group-level location for EF peaks in MNI space was located in the medial-frontopolar cortex, such that individualized EF peaks were placed in a cube with a volume of symmetric/asymmetric: 29cm3/46cm3. Similar results (with slight between-group differences) were found for MUDs that highlighted the role of the medial frontopolar cortex in both healthy and clinical populations. Conclusions: We highlighted that in common DLPFC tES montages, DLPFC was not maximally targeted and the frontopolar area was the area that received the highest EFs. Considering inter-individual and inter-groups variability, we specifically recommended that the frontopolar role should be considered as a potential mechanism underlying the clinical efficacy of DLPFC stimulation.

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Anatomical and fMRI-network comparison of multiple DLPFC targeting strategies for repetitive transcranial magnetic stimulation treatment of depression

Cited by 40 publications

References 80 publications

Pinpointing the precise stimulation targets for brain rehabilitation in early-stage Parkinson’s disease

Pinpointing the precise stimulation targets for brain rehabilitation in early-stage Parkinson’s disease

Are we really targeting and stimulating DLPFC by placing transcranial electrical stimulation (tES) electrodes over F3/F4?

Are we really targeting and stimulating DLPFC by placing tES electrodes over F3/F4?

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