Conscious perception, like the sight of a coffee cup, seems to involve the brain's identification of a stimulus. But conscious input activates more brain regions than are needed to identify coffee cups and faces. It spreads beyond sensory cortex to frontal-parietal association areas, which do not serve stimulus identification as such. What is the role of those regions? Parietal cortex may support the "first person perspective" on the visual world, unconsciously framing the visual object stream. Some prefrontal areas may select and interpret conscious events for executive control. Such functions can be viewed as properties of the subject rather than the object of experience, the "observing self" that may be needed to maintain the conscious state.

Selected references:
Baars BJ, Ramsoy TZ, Laureys S. Brain, conscious experience and the observing self. Trends Neurosci. 2003 ; 26 :671-5
Baars BJ. The conscious access hypothesis: origins and recent evidence. Trends Cogn Sci. 2002; 6 :47-52
Baars BJ. A cognitive theory of consciousness. NY: Cambridge University Press, 1988 Available at www.nsi.edu/users/baars