Monday, November 19, 2007

Brain Complexity: An Update

A smart$#%, or a modern-day imaginary academic Walter Mitty(?), suggests how recent research into electromagnetic fields in the brain might show that brain operations might are far more complex than previously imagined:
I couldn't take it anymore. I raised my hand.

"Yes?" Karmel [an imaginary lecturer] boomed.

I cleared my throat. "I have a question about neurons."

"What is it?" He seemed slightly irritated by having to deviate from the portrait of the hypothalamus that he was so masterfully painting.

"Is the action potential, the electrical charge that travels down the axon of a neuron, in any way similar to electric current that passes through wires in a circuit?"

"The action potential is an electrochemical impulse, whereas the current in wires is purely electrical - though there are some similarities."

"Well, I guess what I was wondering about is this - we know when current passes through a wire it creates an electromagnetic field around that wire. Is it true, then, that when a neuron fires, an electromagnetic field appears around the axon?"

"Yes, in fact some research has actually measured the strength of these magnetic fields." He seemed pleased with his answer.

I twirled my pen between my fingers. "That's interesting, because the magnetic field around a wire alters or creates current in a wire lying near it. Does that mean that any single neuron can influence the action potential of other nearby neurons not just through the synapse, but also through the changes in its magnetic field - and doesn't that add a level of complexity to how the brain functions that far surpasses our current knowledge, especially since our theories primarily emphasize synaptic transmission?"

Karmel's pipe dropped from a stout, upright angle to a limp, downward slant. He pulled it out of his mouth and leaned across his desk towards me, squinting slightly, as if trying to bring me into sharper focus. "I suppose the magnetic fields around axons might influence the activity of other axons, but the communication of information in the brain is primarily through the synapses.... Now, as I was saying, the hypothalamic nuclei are intricately interconnected and receive information from motor systems and from olfactory, gustatory, visual, and somatosensory systems..."

&&&

If quantum computing is what the brain does, the complexity of the brain's opreations is almost boundless. See, e.g., the brief discussion here; the author -- Stuart Hameroff, M.D. -- there states (in part):

Beginning in the early 1980's Benioff, Feynman and others proposed that states in a system - bits in a computer - could interact while in quantum superposition of all possible states, effecting near-infinite parallel computation. Rather than classical Boolean bit states 1 or 0, quantum computers would utilize interactive "qubits" of 1 and 0. If quantum computers can ever be constructed they will have huge advantages in important applications. As the brain/mind has always been cast as current information technology, consciousness may inevitably be seen as some form of quantum computation.
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