The study hypothesized that subthalamic nucleus deep brain stimulation (STN-DBS), a treatment for patients with Parkinson’s Disease, can influence post-stimulation movement depending on the motor state during stimulation. This was based on previous studies where optogenetic stimulation of dorsal striatum neurons in mice revealed that movement speed during stimulation can affect subsequent kinematics. Following electrode implantation, 24 patients were given a visuomotor task to guide a pen to target rectangles oscillating between two halves of a screen, and stimulation was applied during relatively fast and slow motions. MRI-based connectomics and electrocorticography (ECoG) signals over the sensorimotor cortex were also utilized. It was found that electrode stimulation during fast motor states, compared to slow ones, was more successful at counteracting bradykinesia, but stimulation during slow motor states declined movement speed after stimulation. This was further tested during a recovery phase without stimulation, which demonstrated that the observed beneficial effects persisted beyond the stimulation phase. Magnetic resonance imaging (MRI) based connectomics were used to locate areas associated with the speed-dependent effects, identifying the supplementary motor area (SMA) as the optimal region, followed by the putamen, substantia nigra, and globus pallidus externus and internus. Additionally, the study revealed oscillations in electrocorticography (ECoG) signals from the motor cortex that, together with local field potential signals, could decode and predict motor speeds. While the evidence proved that the motor effects of STN-DBS are dependent on the acute motor state at the time of stimulation, as well as highlighting the use of ECoG in future DBS applications, the authors indicate a limitation of not being able to deduce the clinical benefit of speed-selective DBS compared to traditional stimulation.