Sebastian Sten

I am a fourth year student at Linköping University studying for a M.Sc. in biotechnology engineering. Currently however, I am participating in a research preparatory course at the Center for Medical Image Science and Visualization(CMIV). My project is a collaboration between CMIV and the Integrate Systems Biology(ISB) group under supervision by Maria Engström(CMIV) and Gunnar Cedersund(ISB). I work with applying mechanistical modelling in the form of ordinary differential equations(ODE’s) to functional MRI(fMRI) data. The project goal is to evaluate literature-reviewed hypotheses describing the observed blood oxygen level dependent(BOLD)-response.
The BOLD-response is linked to neural activity and describes how the oxygenation of blood changes as a result of increased neural activity. The underlying mechanisms behind the oxygenation changes are still unknown, but a few key hypotheses exist, which are the subject of our evaluation.

The hypothesis which i mainly work on is the metabolic hypothesis. It suggests that a decrease of glucose works as an instigator to the blood oxygenation changes. During increased neural signaling, energy and oxygen consumption goes up, with the increase in energy consumption exceeding the increase in oxygen consumption. To compensate, cerebral blood flow (CBF) is increased to provide a higher inflow of glucose and oxygen to the activated neurons. The increased CBF restores glucose back to baseline levels, but as a side effect, the blood oxygenation increases above baseline due to the mismatch between energy and oxygen consumption.