Abstract: A system and method for mental arousal level regulation of a subject. The system includes at least one sensor and an interface configured to provide a virtual object in a virtual reality environment. A controller is configured to perform a method of mental arousal level regulation including: providing at least one stimulus in the virtual reality environment for a time duration; and acquiring bioelectric signals from the subject via the at least one sensor concurrently with the providing of the at least one stimulus. Based on the bioelectric signals, a mental arousal score for the subject for the time duration is determined. The controller is configured to controllably vary at least one of the virtual object and the at least one stimulus in response to the mental arousal score.