Deep Brain Stimulation (DBS) is a neurological intervention that can treat drug-resistant neurologic and neuropsychiatric disorders such as Parkinson's disease. It involves implanting electrodes into a specific brain region and applying electrical stimulation. This surgical procedure has proven effective in relieving the motor symptoms of such patients, but there needs to be more clarity on the pathways it affects to better refine it. To improve the understanding of one of these pathways called the hyperdirect pathway that is a main focus in PD DBS, nanoparticle-driven fluorescent beads were used to map the regions around the subthalamic nucleus (target of DBS), the primary motor cortex (potential DBS effector), and the ventral anterior nucleus of the thalamus (input to the primary motor cortex). Red and green Lumafluor Retrobeads were injected into four rat brains in these three areas. Histology was collected two days after perfusions, followed by imaging using a fluorescent microscope to identify the nanoparticles. From imaging over 100 slices of these brains, it could be seen that there were a multitude of areas that projected to each of the three areas injected. However, there were only some that displayed a rather strong connection. Furthermore, some areas projected to more than one injection site, displaying just how intricate these pathways are. All the projection sites for the subthalamic nucleus, primary motor cortex, and the ventral anterior nucleus of the thalamus are laid out in a table with the color indigo indicating the strength of the projections. All the data collected provides more specific anatomical information for ongoing DBS work for PD.
