Assuming an individual is physically fit and does not experience abnormalities related to lack of circulation, obesity, or immune disease...what on a neurological level is the basis for feeling like life is on "auto-pilot" for most of the time.
A case study who is well known, is an intelligent individual. He is a male, Caucasian computer scientist under no duress such as financial problems, lack of romance or friendships, lack of nutrition, etc. This individual has the ability to learn things quickly, solve problems robustly, and can pick up spoken languages quickly. However, from experience, any small perturbations in his sleep cycle will cause him to be very, very agitated, very impulsive, have anxiety, and crash/melt down if sustained without sleep for long. By slight perturbation, I mean not an all nighter, but something many people around the world go through from time to time, like two back to back 5 hour nights. In detailed interviews, the person has admitted to feeling like life is on "auto-pilot" most of the time. They cannot explain their actions for every day tasks, and although self admittedly pious (but not overly extremist), wonders if their life is just a multivariable system, one in which everything around them from their coffee cop to their car are just "elements" in a set they call reality, with in their own words, "have properties that detail information relative to to other elements". This person communicates very, very well with others, to the point that they are seen as one of the most social people in mutual inner circles. This person is non violent and does not have any habits or crimes. This person has a high libido. In times of stress, or at random times, this person randomly will text a few close loved ones, "Do you love me?" or "Are you mad?".
Note: This is NOT a real case study nor a request for a medical diagnosis of an individual, as I know both are highly unethical to post here on online. This is part of an educational journal club at a neurophysiology and psychiatry institution. I have submitted my response as it was due last night at midnight. I understand asking others to help me with work is also highly unethical. However, I was just curious if I could sample the waters and see what others think. I am genuinely curious as I thought it was interesting, and I thought it was an interesting case and I had to spend quite a bit researching and explaining my views. Answers are welcome from psychology, neuroscience, psychiatry, biochemistry,, and other offshoots relatable to the cognitive sciences.