Mahlon DeLong, a neurobiologist whose investigations of the area of the brain responsible for controlling movement led to a novel therapy for patients suffering from Parkinson’s disease, has passed away at the age of 86.

DeLong was originally from Des Moines, IA but attended high school in California and received his undergraduate education at Stanford University. After receiving his medical degree from Harvard Medical School, DeLong moved to the National Institutes of Health in the late 1960s, where he became interested in the basal ganglia, a region of the brain implicated in movement.

Based on his own work and that of others as well as existing anatomical information, DeLong proposed a model in which basal ganglia neurons operate in separate circuits. Multiple pathways originate from distinct centers in the cerebral cortex, run through the basal ganglia, and wind up back where they started; the circuits work alongside one another and allow parallel processing of emotions, thoughts, and motor functions.

DeLong’s painstaking elucidation of the physiology of the basal ganglia led to a clinical intervention to help patients with Parkinson’s disease. Alim Louis Benabid, a neurosurgeon in France who had been investigating surgical techniques to alleviate symptoms of tremor, read of DeLong’s work with excitement. DeLong’s neural model aided Benabid in the development of deep brain stimulation of the subthalamic nucleus, a surgical technique that reduces tremors and restores motor function in patients with advanced Parkinson’s disease.

DeLong and Benabid shared the 2014 Lasker~DeBakey Clinical Medical Research Award for their work.