Neurons of the human subthalamic nucleus engage with local delta frequency processes during action cancellation.

The subthalamic nucleus (STN) is a critical hub for inhibitory control, implicated in decision making under conflict and impulsivity. Delta frequency oscillations have also been associated with inhibitory control processes, yet the relationship between human STN neuronal activity and local delta frequencies during response inhibition remains unresolved. Here we recorded STN neurons and local field potentials in patients with Parkinson's disease performing a stop-signal reaction time task during deep brain stimulation surgery. Approximately half of STN neurons responded to a diverse set of behaviorally relevant events including go and stop signals, with stronger go-related firing and enhanced delta phase coupling linked to failed inhibition. Notably, a specific population of bursting STN neurons showed increased delta coupling. These findings suggest that STN neurons integrate go and stop information, and that enhanced delta engagement and bursting may impair inhibitory control, providing insights into the neuronal mechanism of action cancellation.