Theorizing Consciousness

“Theorizing Consciousness” is the fifth chapter of “Consciousness and the Brain:  Deciphering How the Brain Codes our Thoughts” an outstanding book by the French neuroscientist Stanislas Dehaene who is the Chair of Experimental Psychology at the College of France.  This is the sixth consecutive post on this outstanding book.   At this point a theory is needed to explain how subjective introspection relates to objective measurements.  Dr. Dehaene does this  by introducing the notion of a global neuronal workspace.  This global workspace theory was developed along with the psychologist Bernard Baars.

The notion is simple.  Consciousness is brain-wide information sharing.  The human brain has developed efficient long-distance networks, particularly in the prefrontal cortex, to select relevant information and disseminate it throughout the brain.  Consciousness has evolved  to allow us to attend to a piece of information and disseminate it throughout the brain.  Once the information is conscious, it can be flexibly be routed  to other areas according to our current goals.  We can name this information, evaluate it, memorize it, and use it to plan for the future.  We can use it to simulate the prospects of different courses of action.  Computer simulations of neural networks have been run and shown that the global neuronal workspace hypothesis generates precisely the signatures we see in experimental brain recordings.

Many neurons  in the brain differ substantially from other cells in the body.  These are the neurons with exceptionally long axons.   These neurons are most abundant in the prefrontal cortex.   Moreover, each human prefrontal neuron  may host fifteen thousand spines or more. This allows these neurons to transmit information to distant parts of the brain, making the global neuronal workspace truly global.   The prefrontal cortex is the area responsible for decision making and executive control.

The global neuronal workspace hypothesis also explains why vast amounts of knowledge remain inaccessible to our consciousness, namely, there is too much of it. Global workspace theory helps bring order to this jungle of information.  It leads us to pigeonhole our unconscious feats in distinct bins whose brain mechanisms differ radically. There is only a limited amount of attentional resources that can be devoted to conscious processing.  One can argue that the judicious selection of what information to attend to and to devote conscious thought is one of the primary determinant of a happy and successful life.  This is a primary reason why meditation is important.  Contemplation and meditative exercises provide practice in training our attention.

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