A technique will be developed to determine where in the brain the signal in an electroencephalogram (EEG) is originating from in order to generate a voxel-specific EEG, much like the signal coming from an implanted electrode. We propose to call this VIrtual Brain Electrode (VIBE) imaging. The method is based on the principle that red blood cells (RBCs), due to their specific shape and their insulating cell surface, affect the conductivity of the surrounding volume in dependence of their orientation. We propose to influence the orientation of the RBCs by loading them with magnetic nanoparticles and subjecting them to oscillating magnetic fields in a small volume around a field-free point (FFP), as known from Magnetic Particle Imaging (MPI). If, at the same time, we record an EEG, we expect a small modulation to be visible in the recorded signal originating from this volume. We are then able to determine the spatial origin of the EEG signal with high precision and, using methods similar to those used as in MR spectroscopic imaging, we will be able to create a specific 3D map for the origin of the EEG signal. This new methodology would contribute significantly to a better understanding of the normal functioning of the brain, applicable in healthy human subjects. In comparison to fMRI, our method would provide a higher temporal resolution of neuronal activation (equivalent to EEG) and reflect direct electric activation, as opposed to the indirect blood oxygenation-level dependent (BOLD) effect.
This proposal is a planning grant to develop a new imaging technique, termed 'VIBE' (Virtual Brain Electrode). During the planning phase, we will bring together 4 groups with different expertise to demonstrate the feasibility of changing the recorded EEG signal by magnetically labeled blood when applying a localized oscillating magnetic field. This approach will be used to localize the origin of neuronal electrical signals in rats, which could be translated to human subjects in the subsequent 5-year grant phase.
|Khandhar, A P; Keselman, P; Kemp, S J et al. (2017) Evaluation of PEG-coated iron oxide nanoparticles as blood pool tracers for preclinical magnetic particle imaging. Nanoscale 9:1299-1306|