Is the Brain a Spintronic Device?

Spintronics is a new paradigm of electronics based on the spin degree of freedom of the electron. Either adding the spin degree of freedom to conventional charge-based electronic devices or using the spin alone has the potential advantages of nonvolatility, increased data processing speed, decreased electric power consumption, and increased integration densities compared with conventional semiconductor devices.

All spintronic devices act according to the simple scheme: (1) information is stored (written) into spins as a particular spin orientation (up or down), (2) the spins, being attached to mobile electrons, carry the information along a wire, and (3) the information is read at a terminal. Spin orientation of conduction electrons survives for a relatively long time (nanoseconds, compared to tens of femtoseconds during which electron momentum decays), which makes spintronic devices particularly attractive for memory storage and magnetic sensors applications, and, potentially for quantum computing where electron spin would represent a bit (called qubit) of information.

Given the incredible intricacies of the brain's ultrastructure and the billions of years it has had to evolve, it is certainly conceivable that the brain may utilize spintronics. Of course, any talk of quantum mechanical effects in the brain is often greeted with scepticism, thanks to the shameless shenanigans of Roger Penrose and Stuart Hameroff involving Bose-Einstein condensates and microtubules. However, there may be a role for quantum mechanical effects in neural computation yet, and it may be spintronics. Definitely worth further consideration.

Very interesting line of thought lucid, and one that I will do further research into now that you have brought it to my attention. Seriously, I really am intrigued right now. Would you happen to have any formal literature on this subject?

Regardless though, if one subscribes to some sort of dualism where consciousness is more than information processing, then this line of inquiry would be seen as addressing the "easy problem".

I really wish a dualist would come up with an idea on how to address their hard problem.

BTW, I never responded to one of your previous questions about the inadequacies of present day computation and the need to focus on understanding biological cognition. I couldn't agree more. I hope you didn't mistake me for being some crude computationalist because nothing could be further from the truth. My interest in consciousness studies is directed towards all approaches that have the potential to yield real gains in understanding. Unfortunately, I've never witness a dualist framework make any headway whatsoever...although I always invite people to try and amaze me.

The main point I was trying to make to you in the other thread was the apparent theoretical validity of functionalism and the general belief (hope?) that consciousness will eventually be adequately understood to the point where it can be modeled/altered/convalesced/augmented.

hey Technologist, here are a few links to the literature:

http://w3.rz-berlin.mpg.de/~michaeli/membe...ntronicspdf.pdf
http://arxiv.org/pdf/cond-mat/0405528

It seems one potential problem with spintronics is whether spin states are stable long enough to be used in computation. If it turns out that spintronics is not feasible in the brain for one reason or another, then there are still other possibilities for nonconventional classical computation on the molecular scale.

Btw, I don't think you're in any way crude; quite the contrary.

Hmm, well what really has to be looked at here is the relationship between the neurons and how they communicate. Let's not forget that regardless of the biochemical communication of the brain, those chemical molecules used to communicate between individual neurons is made up of elements and those elements are made up of protons, electrons and neutrons. Then we can go deeper into quantum mechanics but anyways

The real question is, does the biochemical structure of the brain denote memory and learning functions or does the physics makeup of the individual chemicals decide the communication? We do know a few things which can lead to further deduction.

First, all electrical currents generate a magnetic field. Since the brain generates its own magenetic field we can logically conclude that a electrical current must run through it.

Since we also know that magentic fields affect the brain state and can change them through devices such as TMS, we can conclude that magnetic fields, acting upon electrical fields are causing changes in the thinking process of the brain.

Since we can logically conclude that electrons do indeed have a influence over the brain and that the chemicals within the brain do have electrons, we know that electrons must play some role.

It is to the extent of this role that is prehaps more important. Magnetic fields can change and affect electron rotation, they can cause electrical alignment and so much more. Since we have deduced that magnetic fields when strong enough, are placed onto the brain, there is a significant change in the brains state - which affects the individuals mind.

Therefore we know that the biochemicals released by neurons are not in themselves soley the communication medium of the brain. Rather we may find through Quantum Electrochemistry, that electrons are at the heart of the biochemical structure of the brain. With this in mind it may be that both theories are somewhat right, since electrons decide the structure and properties of molecules we see that they are essential to the way in which the brain communicates.

I suppose it is to the extent in which one can place Quantum Chemistry or Traditional Neuroscience BioChemistry that is in question. I do not think any answer could be settled upon readily soon, but that the answer itself should lie in testing changes to electrons and measuring their effect. If you were to disrupt electrons in rats brains, what would the effect be?

Surely if electrons are the method of communication between neurons then any disruption should yield strange behaviour from a subject.

Need very strong magnetic field to atract electrons in neurons, brain, becouse field strenght decrease quadraticaly when distance increase linarly. Spin can be only in two states so how it can do somthing? And all thus quantum mechanics is very sensitivy to noise, so I don't think that neurons use somthing more than charge...