WP3: Optimize parameters for effective stimulation based on individual modeling
WP3 focuses on two general objectives:
- To characterize interaction between brain development and effects of tDCS on neuropsychological function.
- To apply individual head modeling and electrical current estimation to guide individualized treatment with tDCS in different stages of development.
The main tasks in this work package are:
- To standardize a neuropsychological battery and MRI, DTI, and EEG protocols between the centers that will perform recruitment of subjects and acquisition of data (Kiel and Coimbra). This will allow the data from the two centers to be pooled together for analysis. Scientists involved in applying these protocols will receive appropriate training.
- To investigate the impact of developmental changes in gray and white matter, of functional and effective connectivity, as well as of cortical information processing on the effects of brain stimulation. Stimulation will be performed following standard protocols to target cortical areas known to be affected in ADHD and ASD: left DLPFC (working memory), right IFG (response inhibition) and bilateral TPJ (perspective taking).
- To study the influence of a concurrent task on effects of tDCS in young subjects.
- To develop and implement a semi-automatic or automatic software pipeline for the pre-processing of the structural and diffusion MRI data and for creating individual paediatric head models based on structural MR images, including electrical conductivity estimates from diffusion tensor MRI. These models will be used to calculate the electric field in the head for standard stimulation protocols mentioned above.
- To pre-process structural and diffusion MRI data and build head models for all subjects of the STIPED project using the development pipeline.
- To optimize stimulation parameters for tDCS on an individual basis, based on the models created in the previous task. The stimulator used in this project (Starstim R32, Neuroelectrics) allows for multiple stimulation electrodes. Optimization therefore involves determining the number and position of the electrodes as well as the current into each one that produces the desired electric field strength in the cortical target area while minimizing the electric field strength in other areas.
- To test the hypothesis that optimized stimulation parameters based on individual models improve effects of brain stimulation. For this purpose, subjects will be stimulated using the standard tDCS protocols and the proposed personalized tDCS protocols. The efficacy of the two types of protocols will be compared by assessing performance during standard cognitive tasks.