Anterior cingulate cortex
It appears to play a role in a wide variety of autonomic functions, such as regulating blood pressure and heart rate.
Effects of sleep deprivation on cognitive performance
The anterior cingulate cortex has been implemented in the process of inhibiting a habitual response or detecting possible conflicts in responses; this is shown by the Stroop test. Studies have found that as little as 36 hours of sleep deprivation cause a performance reduction in tasks requiring these executive functions.
The processes above illustrate a model of controlled versus automatic behavior that was hypothesized by Shallice et al. (1989), called the supervisory attentional system. This system is believed to come into play when intervention of habitual response is necessary. Damage to the prefrontal cortex will cause a breakdown in this system, resulting in utilization behaviors. These behaviors would include spontaneous sequences of action on irrelevant objects in the surroundings with no clear goal in mind. This theory has helped to extend the knowledge we now have on executive functions.