Volume 1, Issue 4 
4th Quarter, 2006


The Dynamics of C-termini of Microtubules in Dendrites: A Possible Clue for the Role of Neural Cytoskeleton in the Functioning of the Brain

Jack Tuszynski, Ph.D.

This article was adapted from a lecture given by Jack Tuszynski at the Second Annual Workshop on Geoethical Nanotechnology on July 20, 2006, at the Green Mountain Retreat of Terasem Movement, Inc., Lincoln, VT.

In this article, Tuszynski explains the complexity of the computational capabilities of the brain and neurons. He demonstrates that these systems are dynamic and programmable, and extrapolates this potential to the idea of building a new nano-universe.

As a humble physicist, I will try to address some simple questions related to computational capabilities within the brain and inside neurons. The cytoskeleton is the main objective of this article, but I will start from a more general perspective by looking at the complexity and diversity of living systems, which are sources of awe to me as a physicist.

When you look at the number of different types of cells in the body and how they cooperate and organize their activities, it is just amazing. There are about two hundred types of cells in the body and ten to the fourteenth cells altogether. They are organized by having about 100,000 different kinds of proteins. They make copies and assemble into intricate structures that perform very complex functions and processes.

Let’s narrow down our inquiry to the neuron system and compare it to the world. I would like to risk a statement that the human brain is as complex as the universe because it has many areas responsible for different activities and roughly ten billion members. This is roughly the size of the planet and the number of people on this planet is about the same as the number of neurons. Yet neurons interact with hundreds of thousands of other neurons on a routine basis. The level of complexity is quite immense. On a daily basis, we humans interact only with maybe a dozen to one hundred people a day.

Speaking of the size and dimensions, I also want to raise the issue of the level of understanding that is required at the different levels of living systems. At the largest level, we use thermodynamics - basically classical concepts - and the lower on the scale you go, the more advanced a theory you must use. There is a pattern. Thus, the complications arise at the intermediate level, cell, and below.

Take a cytoskeleton, where the dimensions and the time scale of processes overlap between the types of classical and quantum regimes. Nanotechnology is very much implicated here. This is indeed a regime where classical meets quantum.

The mathematician and physicist, Walter M. Elsasser[1], coined a very significant number, which is ten to the power of 110. Some of us are very ambitious in saying that, by using this number, we can understand the universe and can predict the future of the universe or evolution of the species.

This number is a humbling wake up call, because there are some inherent limitations in our computational capabilities. This is one of them. It is the product of the size of the universe measured in proton masses times the age of the universe in picoseconds. The meaning is this: If the entire universe was one big computer operating for the age of the universe (fifteen billion years), making transitions on picoseconds times scale which is basic quantum transition, this number would result.

Ten to the power of 110; what does it mean? It means that if you had a set consisting of that many members, you could never even inspect a set. This is an absolute limit. Thus, it is very, very large.

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Footnote
1. Dr. Walter Elsasser (1904-1991) was a physicist and is considered "father" of the geodynamo theory. Wikipedia.com Nov. 7, 2006 11:52AM EST (back to top)

 

 

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