Multimodal investigation of brain activation

The investigation of brain activation patterns belongs to the key aspects in psychiatric and neurological research. The most common approach utilizes functional magnetic resonance imaging (fMRI). Thereby, brain activation is calculated from changing levels of oxygen in the blood. Thus, it is assumed that brain regions that show more activity need more oxygen. However, the derived signal comprises a lot of other aspects including blood flow or volume. Hence, it is a very indirect measure of brain activation. Another possibility to measure brain activation is functional positron emission tomography (fPET). Thereby, radioactive-marked glucose (FDG) is used as a tracer. Active cells use glucose to gain energy. Thus, fPET shows more signal in active brain regions compared to others. However, FDG cannot be fully processed by the cells, which limits the insights into the energy metabolism. The novel MR-based method deuterium magnetic resonance spectroscopy (H-MRS) allows the quantification of certain tracer molecules, without any radiation burden compared to PET. During the deuteration, the hydrogen atoms in the glucose molecule are exchanged with deuterium, a hydrogen isotope with an additional neutron. Active brain regions can use deuterated glucose similar to regular sugar (glucose). Thus, we can use this approach to get deeper insights into energy metabolism of active brain regions. Within the course of this project, we aim to implement a functional H-MRI sequence that allows the investigation of brain activation using a visual stimulation paradigm. Moreover, activation patterns of the brain will be compared between these three approaches.