This document discusses using diffusion MRI (dMRI) to investigate deep brain stimulation (DBS) and locate the subthalamic nucleus (STN). It describes how DBS involves implanting electrodes in specific brain regions to disable parts of the brain. dMRI techniques like DTI and HARDI are used to visualize white matter connections and better locate the STN by subdividing it into motor, limbic and associative parts based on neurological pathways. Postmortem brains are scanned with high-resolution 3T and 9.4T MRI to acquire diffusion images of small cubes around the STN to further explore its connectivity.