The brain and consciousness

[Secular Elation]

What changes does the brain undergo when a person alternates between consciousness and unconsciousness? What is the mechanism in the brain that controls consciousness? Are there certain cells in the brain that "shut down" to cause unconsciousness, such as when we go to sleep? How exactly does the brain function in this regard?

[Magic Primate]

AFAIK there is an architecture of fast 'Re-entrant' pathways, which provide a high degree of integration across certain areas of the brain and which shut down when we are asleep.