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The Neuroscience of Consciousness


Baroness Susan Greenfield




Baroness Susan Greenfield CBE, is a British scientist, writer, broadcaster and member of the House of Lords. Specialising in the physiology of the brain, Susan researches the impact of 21st century technologies on the mind, how the brain generates consciousness and novel approaches to neurodegenerative diseases such as Alzheimer's and Parkinson's.


Two out of the three fundamental mysteries about our place in the universe have already been

resolved. The first is literally about our place in the universe. Many years ago Copernicus told us

that we were not at its centre, that we were just a tiny dot suspended in the abyss. This is an

image of the earth taken from the probe Voyager 1 as it was leaving the solar system from

about six billion kilometres away. All of human history, all of the history of life on Earth, has

taken place on that pale blue dot. The second mystery, Darwin then revealed that we humans

are just one branch, or one twig, of a beautifully rich and delicate evolutionary tree. And that

much of the machinery of life is shared even with the lowliest of our fellow creatures. The third

mystery is that of consciousness, our inner universe.

Now earlier this year, for the third time in my life, I ceased to exist. As the propofol anaesthetic

flowed from the cannula in my wrist, into my bloodstream and then into my brain, there was a

falling apart. A blackness.An absence. And then, I was back. Drowsy and disoriented, but

definitely there. And when you wake from a deep sleep, you might be confused what time it is,

especially when flying somewhere, but you'll know that some time has passed. There seems to

be some basic continuity between your consciousness then, and your consciousness now. But

coming around from a general anesthetic, it could have been five minutes. It could have been

five hours. It could have been five days, or five years. I was simply not there. A premonition of

the oblivion of death. And general anaesthesia doesn't just work on your brain. It doesn't just

work on your mind. It works on your consciousness. By altering the delicate electrochemical

circuitry inside your head, the basic ground state of what it is to be is temporarily abolished. And

in this process lies one of the greatest remaining mysteries in science and philosophy.

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