His discoveries are technical. Just what you would expect. instead of a blinding realization of something overlooked, this research is building up lots of technical detail which at some point in the future will enable us to have a better model of "consciousness":
What do we see when we do these experiments? The first thing that we discovered is that, even when you cannot see a word or a picture, because it is presented in a subliminal condition, it does not mean that your cortex is not processing it. Some people initially thought that subliminal processing meant sub-cortical processing — processing that is not done in the cortex. It's of course completely false and we've known this for a while now. We can see a lot of cortical activation created by a subliminal word. It enters the visual parts of the cortex, and travels through the visual areas of the ventral face of the brain. If the conditions are right, a subliminal word can even access higher levels of processing, including semantic levels. This is something that was highly controversial in psychology, but is now very clear from brain imaging: a subliminal message can travel all the way to the level of the meaning of the word. Your brain can take a pattern of shapes on the retina, and successively turn it into a set of letters, recognize it as word, and access a certain meaning — all of that without any form of consciousness.Put crudely as "consciousness is state of synchrony" doesn't create the "aha!" moment. But I suspect that as the full implication of consciousness is unraveled, there will be no "aha!" moments. But bits and pieces will make sense and there will be the necessary experimental evidence backing up the model. We will simply come to live with the "understanding" that this model implies.
Next comes the obvious question: where is there more activity when you are conscious of the word? If we do this experiment with fMRI, what we see is that two major differences occur. You first see an amplification of activation in the early areas: the very same areas begin to activate much more, as much as tenfold, in for instance, this area that we have been studying and which looks at the spelling of words: the visual word form area.
The second aspect is that several other distant areas of the brain activate. These include areas in the so-called prefrontal cortex, which is in the front of the brain here. In particular, we see activation in the inferior frontal region, as well as in the inferior parietal sectors of the brain. What we find also is that these areas begin to correlate with each other — they co-activate in a coordinated manner. I am for the moment just giving you the facts: amplification and access to distant areas are some of the signatures of consciousness.
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What I propose is that "consciousness is global information in the brain" — information which is shared across different brain areas. I am putting it very strongly, as "consciousness is", because I literally think that's all there is. What we mean by being conscious of a certain piece of information is that it has reached a level of processing in the brain where it can be shared.
Because it is sharable, your Broca's area (or the part of it involved in selecting the words that you are going to speak) is being informed about the identity of what you are seeing, and you become able to name what you are seeing. At the same time, your hippocampus is perhaps informed about what you have just seen, so you can store this representation in memory. Your parietal areas also become informed of what you have seen, so they can orient attention, or decide that this is not something you want to attend to… and so on and so forth. The criterion of information sharing relates to the feeling that we have that, whenever a piece of information is conscious, we can do a very broad array of things with it. It is available.
Now, for such global sharing to occur, at the brain level, special brain architecture is needed. In line with Bernard Baars, who was working from a psychological standpoint and called it a "global workspace", Jean-Pierre Changeux and I termed it the global neuronal workspace. If you look at the associative brain areas, including dorsal parietal and prefrontal cortex, anterior temporal cortex, anterior cingulate, and a number of other sites, what you find is that these areas are tightly intertwined with long distance connections, not just within a hemisphere, but also across the two hemispheres through what is called the corpus callosum. Given the existence of this dense network of long-distance connections, linking so many regions, here is our very simple idea: these distant connections are involved in propagating messages from one area to the next, and at this very high level where areas are strongly interconnected, the density of exchanges imposes a convergence to a single mental object out of what are initially multiple dispersed representations. So this is where the synchronization comes about.
Synchronization is probably a signal for agreement between different brain areas. The areas begin to agree with each other. They converge onto a single mental object. In this picture, each area has its own code. Broca's area has an articulatory record and slightly more anterior to it there is a word code. In the posterior temporal regions, we have an acoustic code, a phonological code, or an orthographic code. The idea is that when you become aware of a word, these codes begin to be synchronized together, and converge to a single integrated mental content.
According to this picture, consciousness is not accomplished by one area alone. There would be no sense in trying to pinpoint consciousness in a single brain area, or in computing the intersection of all the images that exist in the literature on consciousness, in order to find the area for consciousness. Consciousness is a state that involves long distance synchrony between many regions. And during this state, it's not just higher association areas that are activated, because these areas also amplify, in a top-down manner, the lower brain areas that received the sensory message in the first place.
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