Direct visualization of non-human primate subcortical nuclei with contrast-enhanced high field MRI

Subcortical nuclei are increasingly targeted for deep brain stimulation (DBS) and for gene transfer to treat neurological and psychiatric disorders. For a successful outcome in patients, it is critical to place DBS electrodes or infuse viral vectors accurately within targeted nuclei. However current MRI approaches are still limited to localize brainstem and basal ganglia nuclei accurately. By combining ultra-high resolution structural MRI and contrast-enhanced MRI using iron oxide nanoparticles at high field (3T and 7T), we could precisely locate the subcortical nuclei, in particular the subthalamic nucleus in macaques, and validate this location by intracranial electrophysiological mapping. The present data pave the way to a clinical application.