Functional magnetic resonance imaging (fMRI) and Diffusion Tensor Imaging (DTI) are both methods used to visualize the functioning of the brain. Easily said, fMRI displays the computers of the brain (in the gray matter) and DTI displays the wires from the computers (in the white matter). In the past I have worked with SPM and experimented a little with FSL, now I work with BrainVoyager.
fMRI | 
DTI |