This article was adapted from a lecture given by Nancy Woolf, Ph.D., at the 2nd Annual Workshop on Geoethical Nanotechnology, on July 20th, 2006 at the Green Mountain Retreat of Terasem Movement, Inc., Lincoln, VT.

Dr. Woolf, a Neuroscientist with the University of California at Los Angeles, shares her explorations and theories addressing the latest advances in neuronanotechnology concerning some of the important mental illness issues of our society.

My talk on neuro-technology to cure criminality and mental illness will cover a conceptualization that is motivated by nanotechnology[1] and what this very exciting new field may be able to afford us. I want to point out first that in order to elucidate potential cures, we have to first have a physically detailed model of mind and we don’t yet have that.

What I’m going to present today is in essence a simpler, rather than a more complicated, conceptualization of how the brain might encode a single thought. I want to stress that this is an idea, not established fact, and I welcome your constructive criticism. 

Neural [2] networks are part of the solution of figuring out how the brain produces mind but a bio-molecular or biophysical approach is ultimately going to be the most complete.  These different approaches are in their earliest stages.

"One biomolecule of interest is the microtubule and there has been a number of research forays into how the microtubule might participate in higher consciousness."

I’m going to talk in particular about data that I collected over the past ten to fifteen years relevant to how microtubules participate in learning and memory.



Image # 1 - Neural Networks

There are empirical data that I’m going to present, which I’m going to combine with a theoretical conceptualization. The current approach I’m taking is to define the mind as a unique, interwoven collection of thoughts. I’m going to have as a goal the understanding of a single thought.

Some people in the field have been talking about starting with the single molecule or starting with the single neuron [3]. I’m going to start with the single thought and try to come up with some kind of fingerprint or blueprint for a single thought. I’ll give you a little heads-up, I’m going to conceptualize a single thought as a pattern of electromagnetic current transmitted and amplified along some length of a microtubule [4], let’s say, a few microns to five, maybe even ten microns, which in some cases might be the full length of the microtubule inside of a neuron. We call the transmission of current along a microtubule “conductive signaling.”

"The conceptualization is that we have a fingerprint consisting of a microtubule that stores a template for an electromagnetic wave."

And much like you would have for a sound wave, a complex sound wave with timber, there would be a fundamental frequency along with sub-harmonic components. You have something specific that could represent information.

Then I would envision that this would be redundantly expressed. Let’s compare the present notion to the “grandmother” cell, that’s the neuron that represents your grandmother. This idea of a “grandmother cell” has been widely disputed, but the present idea is that there are a lot of microtubules bearing a particular fingerprint in a few, maybe even as few as one neuron, like a ”grandmother cell,” that would be central to a specific idea or piece of information stored somewhere in our brain.

But memory storage is also highly distributed, so exact copies of this template for a pattern of transmission along a stretch of microtubule would also be expected to occur in multiple neurons and in multiple brain areas. We’d have both storage in a highly concentrated form and wider dispersal. I’ll talk more about this and show a picture illustrating what I’m talking about.

Now, the advantage of looking at microtubules is that microtubules lend themselves to nano and neuro-nanotechnology, which is the new frontier for understanding cell function...

...and they are a good starting point for looking for treatments, and even possible cures, for neurological and psychiatric disorders. I’m going to eventually talk about how the nervous system is plastic, and how microtubules seem to be able to permanently encode information.  And that’s something for which I will present empirical evidence. 

If nanotechnological approaches could permanently change the structure of microtubules and alter transmission and amplification of information, then such an approach could conceivably offer a potential cure or long lasting treatment for certain neurological and psychiatric disorders. I’ll talk a little bit more about that, but bear in mind that’s a long way off, this is an optimistic forecast.



Image # 2 - Thoughts

Thoughts are stored in memory, we all know this. That leads to the question how was a memory stored in the first place? Lots of people have been talking about synapses today. I was trained as a neuroscientist and we learned all about synapses [5] and almost all we talked about were synapses, but I’m going to make arguments for sub-synaptic storage of memory rather than synaptic.

This means moving the storage site from the synapse to the microtubules in the dendrite [6] that lie beneath the synapse. Many of our strongest synapses are on something called spines. These are appendages on dendrites that are filled with actin filaments rather than microtubules, but the actin filaments connect with the microtubules.



Image # 3 - Learning

Since we have good evidence that memory might be stored in microtubules, it follows that perhaps memory is stored in the sub-synaptic zone. Now, it would further follow that these microtubules could still serve very basic housekeeping functions, for example, transporting receptor proteins like the AMPA glutamate receptor protein or the NMDA [7] glutamate receptor protein.



Image # 4 - Arguments

These microtubules, if they indeed store information, could then do more than just transport receptors. They could store information that tells those tracks how and when to start transporting excessive amounts of receptors, and to which synapses.