David Chalmers defined consciousness as two problems a while ago, and that's been picked up by the scientific community pretty widely since then.
The "easy problem" is comprised of the neuronal correlates of consciousness: when we "experience" something, as the subject reports it, what's going on in the brain? This is amenable to fMRI, electrophysiological studies, so on. This is considered in the domain of psychology and there's been a lot of progress in recent years. I'd recommend checking out Dr. Christof Koch's work at Caltech for an introduction; he's become a leading figure in the area.
The "hard problem" is the only scientific question which has had no progress since the scientific method was first developed hundreds of years ago. It is the question, "why is there anything at all?" So we can identify precisely what the brain is up to during different cognitive processes and states, even down to the single cell level, but this says nothing as to why it should qualitatively "feel like anything." The classic example is the "redness of red." Why should red look red? We can have a perfect physical explanation for the basis of color, but that doesn't explain the origin of qualia. (Google "qualia," I still can't post links yet). For the moment this isn't usually considered inside the domain of psychology, and the study of the hard problem of consciousness is called phenomenology.
I could understand Dr. Greenfield making such a claim for the hard problem, but not so for the easy problem. Especially with Blue Brain in Lausanne, we should be developing pretty solid models of cognitive processes easily within the next decade.
And madanthonywayne: night terrors aren't associated with imagery. They're a deep sinking feeling, strongly emotional, that somethings terrible and wrong--like a very strong presence of the emotion "fear" itself--but not a specific experience or hallucination. They're pretty common among children, but what you had sounds like normal nightmares.
uh? What else could it be? 