Designing the tools to probe integrative brain functions
Coordinators: Prof. Christoph Braun, Prof. Nikos Logothetis, Prof. Klaus Scheffler
This area focuses on the development of new imaging methods to investigate the healthy and diseased brain. These tools include the non-invasive techniques magnetoencephalography (MEG), electroencephalography (EEG), transcranial magnetic and electrical stimulation (TMS, TES), magnetic resonance methods (MR), positron emission tomography (PET), near-infrared spectroscopy (NIRS), as well as invasive methods with cellular/subcellular resolution, such as multi-photon (MP) microscopy, multichannel extracellular recording and optogenetics. A major goal is to combine information provided by these complementary techniques to improve speed, resolution and sensitivity of reading out brain activity. The CIN has established several research groups and laboratories in this research area. The initiative achieves the pooling of cutting-edge brain imaging methods in centres (MEG, MRI) ensuring a more efficient and appropriate deployment of the more costly tools by users. The CIN has succeeded in implementing a joint professorship in BIomedical Magnetic Resonance, serving as a structural link between the University and the MPI for Biological Cybernetics. The reinforcements and reorganisations made in the first funding period provide a firm basis for future attempts to explore the potential of the high-field systems available at MPI and University (9.4T and 7T scanners for humans plus several high field systems for animals), leading to better non-invasive studies of brain anatomy, connectivity, function and metabolism, in humans and in animals. With the unique high-field MR facilities available in Tübingen we are confident that we will be able substantially to boost MR neuroimaging towards higher spatial (e.g. to assess functional units within cortical layers) and temporal resolution.
The combination of extracellular recordings, optical imaging and multi-photon microscopy with MRI in animals will allow us to get a handle on the basis of MR signal formation in neuronal tissue. Two new junior research groups on complementary aspects of MR physics at the MPI High-Field MR Centre will be conceived so as to further increase the momentum of this research programme.
Planned methodological developments in MEG focus on connectivity analysis using anatomical and functional priors obtained from complementary imaging modalities such as diffusion tensor imaging (DTI), fMRI and from neurophysiological recordings in animals. In the very near future, we will supplement the foetal and adult MEG systems, already available at the CIN, with a mobile mini-SQUID system suitable for studies of infants, thereby allowing CIN researchers to study neuromagnetic activity across the entire human lifespan. The same system will allow studies of neuromagnetic activity in non-human primates, combining non-invasive MEG and invasive microelectrode recordings. To enable the investigation of brain-state dependent information processing, a further target of MEG and MRI research will be the development of advanced online data analysis.
A substantial methodological boost can also be expected from work at the second MR-PET scanner worldwide, which started operating in Tübingen only recently. This system allows for the simultaneous acquisition of anatomical structures, functional activations and metabolic processes. The new device not only offers new diagnostic opportunities, but will also open new possibilities in exploring basic brain mechanisms.