Modelling of axonal B fields for Direct Neuronal Detection (DND) using MRI

Medical imaging has seen great advances over the last twenty years since the introduction of Magnetic Resonance Imaging (MRI). MRI has proved to be a very powerful technique providing the opportunity to observe very detailed body images which has taken the field of body and neuro-imaging to a new level. In addition MRI is widely used for functional imaging with a high spatial resolution. Functional imaging of the brain for the purpose of medical diagnosis and research has relied previously on the hemodynamic response based technique BOLD (Blood Oxygen Level Dependent) fMRI (functional Magnetic Resonance Imaging). Although this is a very powerful and informative imaging method the temporal resolution can be improved by exploiting other information that might be present when imaging the brain. The hypothesis tested here is that the weak neuronal magnetic fields that result from the local neuronal currents cause scanner field perturbations strong enough to appear as contrast on MR images. Such Direct Neuronal Detection (DND) of neuronal currents would allow real time imaging of the electrical activity of detailed regions of the brain, potentially leading to a better understanding of brain functionality.