Ben Lewis-Evans, who also wrote a very good primer on game user research last year (recommended reading for anyone wanting to get into that space), has released the most well-thought out overviews on neurotransmitter physiology and games that I have seen lately. Ben takes the time to actually examine the neurobiological research in the area (which is a vast field of scientific research – and researchers are even examining games/gambling specifically – see e.g.   ), and explains that when it comes to the brain, there are no easy rules-of-thumb that explains everything. The human brain is a vastly complex piece of machinery and there is no simple relationship between dopamine – a word that has been flung around with abandon lately – and engagement.
Ben’s article is also a stellar example of how you can derive a lot of useful knowledge for game design from various fields of scientific research. His list of suggestions for the design of reward systems for games based on scientific research about rewards is an excellent example. Telecom research, Behavioral Economics, Pscyhology, HCI, Population Biology … the amount of knowledge out there we can harvest for use in games is immense.
Neurobiology and the related behavioral biology and -psychology are areas that are important in game analytics, now and in the near future, as we mature current methodologies to integrate more contextual information.
See also Chris Birke’s feature from 2011 which touches on the same topic.
Related interesting piece on glucose metabolic rates while playing games.