Brian Hansen1, Jeremy Flint2,3, Peter Vestergaard-Poulsen1, Stephen J. Blackband2,3
1Center of Functionally Integrative Neuroscience, University of Aarhus, Aarhus, Denmark; 2Department of Neuroscience, University of Florida, Gainesville, FL, USA; 3The McKnight Brain Institute, University of Florida, Gainesville, FL, USA
Functional magnetic resonance imaging (fMRI) has become the leading modality for studying the working brain but the spatiotemporal resolution of the method is somewhat limited. Therefore, alternative MR-based methods for detection of brain activity have been proposed and investigated. Studies have reported functional imaging based on diffusion weighted (DW) MRI. The basis for such DW fMRI is believed to be the sensitivity of DW MRI to changes in tissue micro-structure. However, it remains unclear whether the observed signal changes reflect cell swelling related to neural activation, residual vascular effects, or a combination of both. Here we present evidence of a detectable activity related change in the diffusion weighted MR-signal from the cellular level in live hippocampal slices in the absence of vasculature. Slices are exposed to several substances and the effects evaluated and compared.