The autobiographical self has prompted extended memory, reasoning, imagination, creativity and language. And out of that came the instruments of culture - religions, justice, trade, the arts, science, technology.

More may have been learned about the brain and the mind in the 1990s - the so-called decade of the brain - than during the entire previous history of psychology and neuroscience.

What happens [in a coma] is that you lose the grounding of the self, you no longer have access to any feeling of your own existence.

You're not the same after, say, an incredible love affair that went very well or a love affair that went bad. Or something that happens to your health, or something that happened to somebody else's health, that is close to you. Or something that happens professionally.

There's that effect that is very physical, very down there at the synaptic level, which really means microscopic cellular level, but also molecular level, because all of those structures are operating on an electrochemical basis and so the changes there are very important.

There are ways in which you can make that distinction objective to a certain degree. For example, by looking at responses that could be generated in the brain to exactly the same stimulus and there could be differences there.

In the heart of consciousness is subjectivity, this sense of having a self that observes one's own organism and the world around that organism. That is really the heart of consciousness.