fMRI is an extremely coarse-grained scan and is unlikely to substantially assist in reconstruction. fMRI works by detecting change in blood flow indicating that specific areas of the brain are using more energy to do the task in question. In practice fMRI is so noisy that in order to get good data one generally needs to average a large number of scans of different people together. Otherwise the noise almost completely overrides any data. The smallest region which an fMRI can scan (a voxel) generally has at least millions of distinct neurons. The smallest temporal resolution levels for an fMRI are around a half a second which is a massive length of time for purposes of thought behavior. Overall, the data that this gives for reconstruction is extremely marginal when it is limited to only a handful of scans.