Multimodal integration of functional neuroimaging data

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More and more non-invasive neuroimaging techniques are now available to study normal brain functions but also brain disorders. However, it does not exist any ideal exploration technique able to measure precisely "when" (at a ms scale) and "where" (at a mm scale) an activity occurred in the brain. Each neuroimaging technique measures through different mechanisms (neuronal electricity, oxygen consumption) part of brain activity, being sometimes more dedicated to the question "where?" (good spatial resolution) or to the question "when?" (good temporal resolution). Each of these techniques having its specific advantages and limitations, analyzing each of them individually only provides partial information on underlying brain activity. The objective of my research project is to develop methods to appropriately combine these multimodal data, i.e., data fusion methods, in order to detect additional information that could be missed by considering each modality individually. A typical challenge is to combine modalities measuring directly neuronal activity with high temporal resolution with other modalities measuring indirectly the same function with high spatial resolution, through hemodynamic processes for instance. Most neuroimaging techniques have been developed in order to be sensitive to different brain signals: (1) direct measurements of neuronal bioelectric activity (from scalp recordings) and (2) indirect measurement of brain activity through hemodynamic processes measuring blood flow providing oxygen to the active neurons. The objective of my work is to accurately characterize the link between these two types of measurements when studying normal brain activity but also abnormal epileptic discharges. The first objective will be to localize, within the brain, fluctuations of blood flow measured using optic fibres placed on the scalp. The second objective will consist in using these different modalities to assess the integrity of this link between neuronal bioelectric activity and hemodynamic processes. The third objective will consist in extracting relevant information on brain activity using these multimodal data to characterize resting state fluctuations.