Abstract: Disclosed herein is a system and method for training a subject to self-regulate neural variability. The system and method implements a prefrontal cortex brain-computer interface (BCI) and a method that allows subjects to use neurofeedback to produce a desired neural activity by regulation of their arousal levels to stabilize their neural activity across a timescale of seconds or minutes. The system comprises a prefrontal cortex brain-computer interface (BCI) to train subjects to use neurofeedback to produce desired neural activity. Subjects used the disclosed system and method, which includes BCI feedback, to self-regulate their arousal levels and successfully stabilize their neural activity.