The aim of this thesis is the computational study of the electrical field distribution during
transcranial direct current stimulation (tDCS). Initially, the anatomy and the importance of some
brain tissues are mentioned. In the following, the organization of memory, the stages of sleep and
the relationship between sleep and memory are given. The method of transcranial direct current
stimulation is then described. A brief reference to the electromagnetic theory and the computational
techniques, which were used, follow. Finally, the computational models are described. The first is a
simple brain model (stratified model) and two realistic human models of an adult man and an
adult woman, named as Duke and Ella, from the Virtual Population project. The latter are also
studied with dielectric properties corresponding to an older age. The clinical experiment, which is
closely related to the present work, is also mentioned. Finally, the results of all models (percentage
diagrams and pictures of electrical field distribution) are given and discussed. The last
chapter contains the conclusions of the work.
38. MRI vs. fMRI
MRI fMRI
Only one image collected
(one full head volume)
Series of several images
collected over time
(e.g., 1 full head volume
every 2 seconds over the
course of several minutes)
High Resolution
(<1 mm3)
Lower Resolution
(~3 mm3)