Quote of note:

The brain’s ability to “switch off” the self may have evolved as a protective mechanism, he suggests. “If there is a sudden danger, such as the appearance of a snake, it is not helpful to stand around wondering how one feels about the situation,” Goldberg points out.

Watching the brain 'switch off' self-awareness
18:00 19 April 2006
NewScientist.com news service
Gaia Vince

Everybody has experienced a sense of “losing oneself” in an activity – being totally absorbed in a task, a movie or sex. Now researchers have caught the brain in the act.

Goldberg found that when the sensory stimulus was shown slowly, and when a personal emotional response was required, the volunteers showed activity in the superfrontal gyrus – the brain region associated with self-awareness-related function.

But when the card flipping and musical sequences were rapid, there was no activity in the superfrontal gyrus, despite activity in the sensory cortex and related structures.

“The regions of the brain involved in introspection and sensory perception are completely segregated, although well connected,” says Goldberg, “and when the brain needs to divert all its resources to carry out a difficult task, the self-related cortex is inhibited.”