Sunday, March 7, 2010

Mind and brain - partners in movement (Books - i of the vortex by Rodolfo Llinas)

Rodolfo Llinas's 2001 book, i of the vortex attempts to bridge our knowledge about the concepts of mind and self and our knowledge about brain cells. Somehow when our brain receives sensory stimuli from some source in the world (say a little red car driving down the street) - light acts upon the retina, waves of compressed air act upon the ear's basilar membrane - if that information is to be used, its gets recreated as an image represented in the language of the brain. If we aspire to own such a car, our interest will perceive the its meaning as the object we are saving to buy. If we are in the middle of the street and the car is driving towards us at 80 miles per hour, we will perceive its meaning as a heavy piece of metal with potential to do us harm and a good reason to move our legs and get out of the way. The pieces of information are reassembled in such a way that they are relevant to given states. An image is made of 'car' in one context or another and yet, if we opened the brain and looked at the tissue that made that image, we would see nothing that looks like a car. The car doesn't drive onto ones retina, and resemble a car as it makes its journey from our eye to our thalamus to our cortex. What goes in does not come out, but is an image translated into the language of electrical changes spoken by our neurons and generated according to a context that gives the image potential use. Mind, according to Llinas, is the present internal state that determines the creation of that image relative to its use given that state. Relative to predictions it makes about the events occurring around us, the brain plans movement, executing the command to carry out such movement if it is necessary.
The central generation of movement and the generation of mindness are deeply related; they are in fact different parts of the same process. In my view, from its very evolutionary inception mindness is the internalization of movement.
However, different states are concurrently overlapping and vying for primacy in each of us at any one moment. In the example above, our red car could be not only our heart's desire but also a potentially lethal projectile at the same time. Yet, if our brain is to make its predictions useful, there must be some arbiter of these concurrent states.
Self is the centralization of prediction.
Llinas then relates how potential movement may have determined the evolution of the brain as its looks today and how the brain's cells carry out the twin functions of creation of states and prediction of future needs, given what we know about their properties. Which has taken me to the half-way point.

Llinas's writing is cogent and quickly paced. This book is really philosophy married with neuroscience and Llinas is skilled at describing abstract concepts, attaching them to the structural and electrical facts of neurons, without losing either thread. Some ability to walk around in the language of contemporary neuroscience is necessary to get through the chapter on neurons. It is written at a graduate text book level, but having only one chapter to spend on these intricacies he writes an effective summary. I don't know if that will make it easier for the first-time reader or more difficult. I will know better when I reach the end of his argument if one could skim this chapter and still get the gist of the integration Llinas is trying to build between brain and mind. His is a grandiose plan - the flip side of Buzsaki's more narrowly focused and longer work on the brain's oscillatory properties. Llinas seems to want to devise the integrated theory of absolutely everything - mind, brain, self, consciousness - we have all the information we need, the premise seems to say, all that's left is for me to tie it all together. I'm glad to report that so far, he builds his story methodically and makes his connections modestly.

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