Inter-Individual Variation during Transcranial Direct Current Stimulation and Normalization of Dose Using MRI-Derived...

Area of Science:

• Neuroscience
• Biomedical Engineering

Background:

• Transcranial Direct Current Stimulation (tDCS) is a non-invasive neuromodulation technique used for neuropsychiatric disorders, rehabilitation, and cognitive enhancement.
• Variability in tDCS response is a challenge, potentially due to differences in applied current intensity influenced by electrode montage and individual anatomy.
• Computational Finite Element Method (FEM) simulations using subject-specific MRI data are crucial for predicting brain current flow.

Purpose of the Study:

• To investigate the variability of current flow in the brain during tDCS across different anatomical individuals.
• To model multiple tDCS montages in typical adults to understand inter-individual differences in current distribution.
• To explore methods for normalizing tDCS dose by customizing it to individual anatomy.

Main Methods:

• Modeling of multiple tDCS montages in three adult subjects (ages 34-41).
• Utilizing computational FEM simulations based on subject-specific anatomical MRI data.
• Comparison of conventional pad stimulation and High-Definition tDCS (HD-tDCS) montages.

Main Results:

• Conventional tDCS resulted in diffuse current modulation, with peak flow between electrodes, varying in intensity and location across subjects.
• HD-tDCS demonstrated more restricted current flow within the electrode perimeter for all subjects.
• Individual cortical anatomy, including gyri and sulci, significantly influenced the current flow profile for both stimulation types.

Conclusions:

• Subject-specific modeling is essential for predicting and understanding tDCS current flow.
• Customizing tDCS dose based on individual anatomy can lead to more consistent and effective neuromodulation.
• This approach holds promise for optimizing tDCS therapy for various applications.