Basal ganglia (BG) are a group of nuclei in our brain and control voluntary movements, and their malfunctions induce motor disorders, such as Parkinson’s disease and dystonia. Among BG nuclei, the subthalamic nucleus (STN) plays an important role; its lesion induces a motor disorder called hemiballismus, and applying high-frequency electrical stimulation to the STN, known as deep brain stimulation of the STN (STN-DBS), can treat Parkinson’s disease. In the present study, we used Japanese monkeys and investigated how STN neurons receive cortical inputs by recording neuronal activity in the STN and chemical blockade of signal transmission with local drug injections. We have found that the STN receives cortical inputs through two different pathways with different timing; one is the hyperdirect pathway by which the motor cortex projects directly to the STN, and the other is the indirect pathway by which the motor cortex projects to the STN indirectly through the putamen and the external segment of the globus pallidus, other basal ganglia nuclei.

This study will give us basic knowledge to understand the pathophysiology of movement disorders and beneficial mechanism of STN-DBS, and will lead us to development of new therapies.  

Summary figure showing that information originating from the motor cortex reaches the subthalamic nucleus (STN) through the putamen (Put) and the external segment of the globus pallidus (GPe).

Funding

Ministry of Education, Culture, Sports, Science and Technology (MEXT) KAKENHI (“Non-linear Neuro-oscillology,”), Japan Society for the Promotion of Science KAKENHI, Japan Science and Technology Agency Core Research for Evolutional Science and Technology, Japan Agency for Medical Research and Development, and MEXT Scholarship.