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Heya, Fabi, science has made a great deal of progress on where consciousness resides in the body in the last 30 years. For example, they recently found an area in the brain that will turn off consciousness when electrically stimulated. A book called Consciousness and the Brain may be of interest to your son. Here's a thought-provoking review from a Stanford researcher (http://www.bobblum.com/) that summarizes what the book is about

(Five Stars) Ignition, a self-reinforcing avalanche (and with panache!)

As a physician and Stanford researcher (initially in artificial intelligence and currently in cognitive neuroscience), I have been interested in consciousness research for 50 years. How does the brain create consciousness? And, if this is "simply" a story of billions of spiking neurons talking to one another, can it be done in silicon? (If so, this may occasion a profound turning point in human history.)

I have followed Professor Stan Dehaene's prestigious journal publications for a decade as he has amassed a wealth of evidence supporting the view that consciousness is 1) experimentally accessible, 2) has reliable neural correlates (signatures), and 3) is functionally important . Dehaene (a professor at the College de France in Paris and director of the INSERM Cognitive Neuroimaging Unit) is one of the world's leading scholars of consciousness. Fortunately for us, his literary agent, John Brockman (of "Edge" fame) persuaded him to write this popular work.

That Dehaene writes this well in English makes me wonder how spectacularly he must write in his native French. We are not only transported to the cutting edge of research on consciousness, but the voyage is a thrill. As expected, Dehaene is thoroughly steeped in the history of consciousness from Plato, through Descartes, Hume, and the Continental philosophers. His writing is also filled with references to French art, literature, and humanism (like serotonin molecules, that culture seems to have diffused from the Louvre down the Boulevard Saint-Michel and become bound in this book.)

Right from the start (see the beautiful, free Introduction on Amazon) he reminds us that it all began in the caves at Lascaux with the depiction of a dreamer's soul wafting about like a sparrow. Deftly weaving ancient Egyptian mythology with the Upanishads, he transitions to Descartes and his alleged "Error." Rightfully defending his countryman, Dehaene takes contemporary pop-neurosci to task. Descartes was no dualist (body + immaterial soul) blinded by religion. Rather, he was genuinely grappling with the central problem of this book and the field. How does conscious perception, reflection, and deliberation emanate from a machine?

In seven chapters, Dehaene carefully steps us through all the evidence (from his large Paris group and the world's other top labs) of the brain's signatures of consciousness.

How can one even study consciousness in the lab? (Chapter 1) The key innovation was the discovery and exploitation of "minimal contrast" phenomena. When presented just too faintly, too rapidly. or when masked they are completely invisible. But, increase the intensity, duration, or remove the mask and there they are, plain as day. I'll list these, but do yourself a favor and go to YouTube to see them for yourself: motion-induced blindness, change blindness, attentional blink, binocular rivalry, multistable perception. Now you see it; now you don't. (Also, go to Charlie Rose's website and look at the episode on consciousness in which Nobelist Eric Kandel interviews Dehaene and other stars of this field.)

We are obviously conscious, but is there any neural processing of which we are NOT conscious?
(Chapter 2) Yes, most of it! Non-conscious and pre-conscious processing is ubiquitous, functional, and essential. He reviews fascinating experiments that reveal the pervasive and essential role of non-conscious processing in language, vision, hearing, and action. Consciousness is the tip of the iceberg.

Perhaps consciousness is epiphenomenal (a non-functional add-on, like the roar of a jet plane). In Chapter 3 he dismisses that old, profoundly counter-intuitive proposition. His argument here is reminiscent of Kahneman's Thinking Fast and Slow. Fast (nonconscious) thought is fine for practiced, routine, reflexive speech and action. But thinking and action marked by careful deliberation and planning requires consciousness: the ability to maintain a percept in working memory and mull it over.

Chapter 4 displays the core findings of the experimental work: the neural signatures of consciousness. These are what Nobelist Francis Crick and collaborator Christof Koch called the neural correlates of consciousness. (See Koch's excellent work "The Quest for Consciousness") Even invisible, unseen (subliminal) stimuli excite chains of neural firing but only in primary sensory areas. However, when a stimulus crosses the threshold into consciousness, the neural firing is strongly amplified in intensity and distribution as many brain regions ignite and communicate especially prefrontal, parietal, and anterior temporal areas.

In Chapter 5 he describes a tentative theory that accounts for the experimental findings: the global neuronal workspace theory. I'm old enough to recall the origin of this theory as the blackboard model from 1970s AI research sponsored by DARPA that led to the then famous Hearsay-II speech understanding system from CMU. In an interesting quirk of history, this excellent work was dragged into oblivion by the AI Winter of the 1980s. But, the theory itself became resurrected as a theory of consciousness by psychologist Bernard Baars. (See Baars' 1988 A Cognitive Theory of Consciousness). With the 1990 advent of fMRI, this theory became ripe for experimental verification. Entrez Professeur Dehaene. Not only can he explain the lab details from Chapter 4, he has also built a computer simulation of a spiking neural network that exhibits the same behavior.

As you may know, Europe has just embarked on a ten year 1.5 billion dollar project to simulate the human brain. While this project may seem to be irrationally ambitious, I am comforted in knowing that Dehaene is one of the scientists at the helm.

Chapter 6 deals with the crucial topic of coma and vegetative states. It opens poignantly with the case of Jean-Dominique Bauby, the Editor of Elle, who had a brain stem stroke, and though entirely paralyzed (save for one eye), wrote an entire book "The Diving Bell and The Butterfly" by blinking that eye. EEG, MEG, and fMRI signatures of consciousness may in the future help us to decide which coma patients are conscious and which are not.

He closes in Chapter 7 with the future: tests for animal consciousness and machine consciousness. While machine consciousness may someday be possible, it will not happen soon. Nonetheless, this work paves the way to it by showing the functional properties of the only system that we know is conscious: ourselves.

Although I've read widely on this topic (and cover AI and Stanford neuroscience on my website: bobblum) , there was much here that was new to me. This is an outstanding work on the basis of both scientific and literary merit.​