10/23/2006

Review: I of the Vortex

What is the "self" in neural terms? Few would be bold enough to claim an answer to that question. Yet in "I of the Vortex: From Neurons to Self," Rodolfo Llinas sketches a very compelling picture of how the self, consciousness, and intelligence may arise in the brain.

Essentially, Llinas's argument goes as follows. First, brains are really only found in animals that move (so, obviously, plants do not have brains). In fact, at least one animal - the sea squirt - actually devours its own brain once it no longer needs to move. Although simple movements might be caused by oscillatory pattern generators in the spinal cord, the brain is necessary for more complex, sensory-guided movement. Why should this be so?

The answer Llinas provides is prediction, or in other words, a sensorimotor internal model of the world based on "dt lookahead" functions, interfacing the motor and sensory systems. Synchronized oscillations from the cerebellum (Llinas's area of expertise) carry out the motor-side of this computation, giving rise to the characteristic 8-12 Hz periodicity of the neural signals that command voluntary movements. At a higher frequency (40 Hz), other neuronal oscillations throughout the thalamocortical system serve to bind sensory representations together. And the subjective, cognitive correlate of the intersection of these oscillations is no less than the self: "this temporally coherent event that binds, in the time domain, the fractured components of external and internal reality into a single construct is what we call the 'self.'"

But wait, doesn't that mean that all animals have a sense of "self"- even the lowly sea squirt (at least before it eats its brain)? It would seem so. But that's not the end of Llinas's more controversial claims. Llinas also suggests that neural networks explain "very little concerning the actual functioning of the nervous system itself," advocating instead the idea that most of our cognitive abilities are genetically prewired at birth. Along these lines, Llinas endorses Chomsky's idea that genes may to a large extent determine language, and furthermore that language exists in many species besides homo sapiens.

It is here that "I of the Vortex" starts to seem more like a manifesto than a careful scientific analysis. For example, after introducing the basics of neurophysiology and comparative neurology in the first half of the book, Llinas skips the cognitive level of analysis almost altogether and starts extrapolating directly to issues of consciousness, awareness, and selfhood. This bias against direct investigations of cognition (something arguably very important for understanding consciousness) is nowhere more apparent than when he refers to cognitive neuroscience as "neophrenology." But without this important middle-level of analysis, Llinas is mostly shooting from the hip in the second half of the book - and aiming for concepts that are simply too far removed from Llinas's expertise in cellular neurophysiology.

On the whole, Llinas has done an admirable job of outlining one particular view of how neuronal dynamics may give rise to consciousness in an embodied cognition framework. In this sense, "I of the Vortex" makes an excellent companion to books such as Jeff Hawkins' "On Intelligence," and to Steven Rose's "The Future of the Brain," both of which come to similar conclusions but based on very different assumptions, biases, and areas of expertise.

Other Book Review Posts at Developing Intelligence:
Review: Darwin Among the Machines
Review: The Three Pound Enigma
Review: Everything Bad Is Good For You
Review: The Future of the Brain

2 Comments:

Blogger whitewhale said...

Llinas may be shooting from the hip but he's a marksman.

Its hard to describe consciousness, and I think Llinas book is more succint and clear than similar "broad ideas on neuro" books by Baars, Koch, Hobson, Sejnowski, or Edelman.

There may be little cost of ignoring cognitive science completely, when chemistry is remembered. I think that "i of the vortex" gets credit for its short manuscript and stellar title.

10/28/2006 08:42:00 PM  
Blogger Chris Chatham said...

Hey Whitewhale - I may have been a little hard on "i of the vortex," and I agree with you that it's a catchy title and a clear & succinct book. I haven't read all of the other "broad ideas on neuro" books you mention either.

10/29/2006 08:32:00 AM  

Post a Comment

Links to this post:

Create a Link

<< Home