Estimation of brain tissue response by electrical stimulation in a subject-specific model implemented by conductivity tensor imaging

• Published in: Frontiers in neuroscience Vol. 17; p. 1197452
• Main Authors: Katoch, Nitish, Kim, Youngsung, Choi, Bup Kyung, Ha, Sang Woo, Kim, Tae Hoon, Yoon, Eun Ju, Song, Sang Gook, Kim, Jin Woong, Kim, Hyung Joong
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Research Foundation 23.05.2023; Frontiers Media S.A
• Subjects: Brain; Cerebrospinal fluid; Computational neuroscience; conductivity tensor; current density; electric field; Electric fields; electrical stimulation; Electrical stimulation of the brain; Electrical stimuli; Electrodes; ESB; Experiments; Feasibility studies; magnetic resonance imaging; Mathematical models; Mental disorders; Neuroimaging; Neurological diseases; Neuroscience; Scanners; Software; Substantia alba; Substantia grisea; Tomography; transcranial direct current stimulation; United Kingdom > UK; conductivity tensor; current density; electrical stimulation; magnetic resonance imaging; electric field; transcranial direct current stimulation
• ISSN: 1662-453X; 1662-4548; 1662-453X
• DOI: 10.3389/fnins.2023.1197452

Electrical stimulation such as transcranial direct current stimulation (tDCS) is widely used to treat neuropsychiatric diseases and neurological disorders. Computational modeling is an important approach to understand the mechanisms underlying tDCS and optimize treatment planning. When applying computational modeling to treatment planning, uncertainties exist due to insufficient conductivity information inside the brain. In this feasibility study, we performed in vivo MR-based conductivity tensor imaging (CTI) experiments on the entire brain to precisely estimate the tissue response to the electrical stimulation. A recent CTI method was applied to obtain low-frequency conductivity tensor images. Subject-specific three-dimensional finite element models (FEMs) of the head were implemented by segmenting anatomical MR images and integrating a conductivity tensor distribution. The electric field and current density of brain tissues following electrical stimulation were calculated using a conductivity tensor-based model and compared to results using an isotropic conductivity model from literature values. The current density by the conductivity tensor was different from the isotropic conductivity model, with an average relative difference | rD | of 52 to 73%, respectively, across two normal volunteers. When applied to two tDCS electrode montages of C3-FP2 and F4-F3, the current density showed a focused distribution with high signal intensity which is consistent with the current flowing from the anode to the cathode electrodes through the white matter. The gray matter tended to carry larger amounts of current densities regardless of directional information. We suggest this CTI-based subject-specific model can provide detailed information on tissue responses for personalized tDCS treatment planning.