Saturday, March 01, 2008

Oscillatory Matters

Ginger Campbell at Brain Science Podcasts has put out a very nice podcast interviewing György Buzsáki (pronounced Yuri Bu-shock-i) about his book, Rhythms of the Brain. I have read this book, and posted about it here a number of times here and also here.

My favorite line in the book is still the very first sentence -
"The short punch line of this book is that brains are foretelling devices and their predictive powers emerge from the various rhythms they perpetually generate. At the same time, brain activity can be tuned to become an ideal observer of the environment, due to an organized system of rhythms."

In the interview, Buzsáki points out that oscillations are part of nature, and that neurons, being part of nature, are just doing what comes naturally. In his interview, he stresses that oscillations are economical for the nervous system to produce, that they provide a means by which the whole system can synchronize itself "almost for free."

The reason I found his book and this podcast so riveting is because my line of work (Physical Therapy/Physiotherapy) has always been to do with "movement" at every level of the human system. I have read lots about it, tracking "movement":

1. all the way in to the motor cortex, then premotor, where firing patterns precede "awareness", conscious will, decision-making,

2. embryology, "movement" of cells to destinations through mechanisms of chemo-attraction/repulsion,

3. evolution or "movement" of life through time and form,

4. "movement" that occurs in organisms without nervous systems,

5. "movement" generated in humans (and other multicellular creatures) that do have nervous systems,

6. remembering that "movement" begins before the nervous system ever gets any sensory perturbation at all (e.g., chicks etc. pecking their way out of an egg, fetuses "kicking"),

... all presumably because life can stir, can "move" of its own accord, simply because of biochemical processes.

I loved hearing that oscillation (or neural "movement") seems to be so inherent, so fundamental, such an energy saver for an oxygen-expensive system like the nervous system - a means by which it can "perturb" itself.

Buzsáki used a clapping example in the podcast and in his video as well. My understanding is that this illustrates that any signal (including any neuronal signal) can be perturbed, amplified, sharpened, synchronized, stretched into greater contrast without wasting energy.

Logically then, neuroplasticity is merely an outcome, therefore, a simple function of this inherent oscillatory "movement", taking advantage of this ability "nature"/neuron cell assembly/ brains have to be able to talk to "it"self/ themselves. Do neurons see a chance to save some energy and go for it? or is it a completely passive process like woodchips being washed up on a beach by ocean waves? I'd bank on the latter but who knows, maybe Varela/Maturana are right about "living" cells having "cognition" of a sort, maybe "cognition" that boils down to a simple proclivity for being "lazy" thermodynamically. Get enough of these lazy cells together and you have a functional multicellular organism that runs on "almost free" oscillatory synchrony, by cooperating to rectify/enhance the signal.

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