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Neurons can operate in reverse

eurekalert.org

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Re: Neurons can operate in reverse

#21

Post by a-priori »

ihodes wrote: post #20
a-priori wrote: post #6

I didn't think this was new... I remember hearing about this effect last year and having it attributed to Oligodendrocytes, I believe. That said, it's a very important development, because until the last few years the glial cells have mostly been considered to be support cells (e.g. supplying nutrients to the neurons, removing waste products and dead cells, myelinating axons, etc.). But, now we know that they can aff…

This article was from last year (don't know if it's the one you're thinking of), but the paper just theorizes that glia may be involved in the described mechanism. I think we can be fairly certain that glial cells are involved in neuronal communications, but I'd not say this paper at all proves that.

Now that I think about it, I believe I was remembering an interview on the Brain Science podcast with Douglas Fields[1], author of The Other Brain[2].

So sorry, but I don't have primary sources for what I said in my earlier comment...

[1]: http://www.brainsciencepodcast.com/bsp/2010/5/12/exploring-g...

[2]: http://theotherbrainbook.com/

Re: Neurons can operate in reverse

#23

Post by ihodes »

a-priori wrote: post #21
ihodes wrote: post #20

Earlier quoted context omitted.

This article was from last year (don't know if it's the one you're thinking of), but the paper just theorizes that glia may be involved in the described mechanism. I think we can be fairly certain that glial cells are involved in neuronal communications, but I'd not say this paper at all proves that.

Now that I think about it, I believe I was remembering an interview on the Brain Science podcast with Douglas Fields[1], author of The Other Brain[2]. So sorry, but I don't have primary sources for what I said in my earlier comment... [1]: http://www.brainsciencepodcast.com/bsp/2010/5/12/exploring-g... [2]: http://theotherbrainbook.com/

Oh there have definitely been studies on it (a good review: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2062484/), and without a doubt they communicate. It's just that this paper didn't really address that.

What was remarkable about this paper was that they demonstrated action potentials (basically, the neuron's relative charge depolarizing) could start not only in the soma, but in the axon.

Re: Neurons can operate in reverse

#24

Post by bioh42_2 »

ihodes wrote: post #14
marshray wrote: post #13

What else can they do "after all" ? Is it simply a matter of time before we find a quantum computer in there?

Roger Penrose (among many others) thinks so: http://en.wikipedia.org/wiki/Quantum_mind

We have known that enzymes make use of quantum tunneling for a while: http://en.wikipedia.org/wiki/Enzyme_catalysis#Quantum_tunnel...

And since our brain, like the rest of our bodies, is full of enzymes, I would in no way be surprised if we find other quantum effects.

Re: Neurons can operate in reverse

#25

Post by ihodes »

bioh42_2 wrote: post #24
ihodes wrote: post #14

Earlier quoted context omitted.

Roger Penrose (among many others) thinks so: http://en.wikipedia.org/wiki/Quantum_mind

We have known that enzymes make use of quantum tunneling for a while: http://en.wikipedia.org/wiki/Enzyme_catalysis#Quantum_tunnel... And since our brain, like the rest of our bodies, is full of enzymes, I would in no way be surprised if we find other quantum effects.

Right. The question is not whether or not there eist quantum effects in the brain, but whether they have any effect at all. Right now, there are only theories: no empirical data exists to prove or disprove the theory.

Re: Neurons can operate in reverse

#26

Post by marshray »

ihodes wrote: post #25
bioh42_2 wrote: post #24

Earlier quoted context omitted.

We have known that enzymes make use of quantum tunneling for a while: http://en.wikipedia.org/wiki/Enzyme_catalysis#Quantum_tunnel... And since our brain, like the rest of our bodies, is full of enzymes, I would in no way be surprised if we find other quantum effects.

Right. The question is not whether or not there eist quantum effects in the brain, but whether they have any effect at all. Right now, there are only theories: no empirical data exists to prove or disprove the theory.

Wouldn't it just be cool as heck if it turned out that this enabled "spooky action at a distance" ESP-type stuff under conscious control by the brain?

Heck, I'd settle for a just a built-in magnetometer or something so I didn't get lost.

(Sorry for the content-free post, I'm feeling slightly more whimsical than usual this Friday afternoon.)

Re: Neurons can operate in reverse

#27

Post by Florin_Andrei »

tgflynn wrote: post #17

What I find surprising about this type of news is why the brain would need so much complexity. It seems to me that a network with 10^11 neurons and 10^14 synapses should have sufficient computational power to carry out the information processing tasks that humans perform using only simple function neurons. This belief is based on the following observations : - I have personal experience with ANN's with only thousands…

> why the brain would need so much complexity

Be more successful in avoiding predators, acquiring food, mating.

Mother Nature will get every little advantage she could scrounge up.

Re: Neurons can operate in reverse

#28

Post by Udo »

tgflynn wrote: post #17

What I find surprising about this type of news is why the brain would need so much complexity. It seems to me that a network with 10^11 neurons and 10^14 synapses should have sufficient computational power to carry out the information processing tasks that humans perform using only simple function neurons. This belief is based on the following observations : - I have personal experience with ANN's with only thousands…

It's not about complexity or raw computational power, it's about functionality. One area where brain research still struggles to model the basics is how the brain actually integrates information over time, and how internal models and representations are formed.

The "classical" synaptic response model was always good at explaining basic signal transmission, but it was essentially stateless. Now we know that neurons are far from stateless, there is extensive chemical modification going on working at different timescales and I guess this "new" discovery is also an important piece that was missing from the standard model. It may explain advanced neuronal states that surpasses simple chemical sensitization and suppression - and it may also provide hints about how feedback works in learning and building internal representations.

ANNs and other AI techniques are getting very good and efficient, but one reason why general artificial intelligence (as in artificial persons) continues to escape us is that we still don't have a good model how the brain organizes and improves itself to form a consistent but autonomously adapting unit which can rightfully be called a mind. I hope that AI people can use these pointers provided by bio research and advance toward this goal.

Re: Neurons can operate in reverse

#29

Post by sesqu »

marshray wrote: post #26
ihodes wrote: post #25

Earlier quoted context omitted.

Right. The question is not whether or not there eist quantum effects in the brain, but whether they have any effect at all. Right now, there are only theories: no empirical data exists to prove or disprove the theory.

Wouldn't it just be cool as heck if it turned out that this enabled "spooky action at a distance" ESP-type stuff under conscious control by the brain? Heck, I'd settle for a just a built-in magnetometer or something so I didn't get lost. (Sorry for the content-free post, I'm feeling slightly more whimsical than usual this Friday afternoon.)

People may have a crappy built-in magnetometer, but it seems you don't need one - just a lot of practice. There are cultures that put such weight on the cardinal directions that they always maintain a sense of where they are facing.

en.wikipedia.org/wiki/Magnetoception#In_humans http://www.isegoria.net/2010/08/does-your-language-shape-how...

Re: Neurons can operate in reverse

#30

Post by tocomment »

streptomycin wrote: post #11
busyant wrote: post #4

Earlier quoted context omitted.

> contrary to what was always believed This is the statement that always comes back to bite biologists. If it's "theoretically possible", biology is probably already doing it somewhere.

Not really. For instance, people have been looking for 5'-3' DNA polymerase for decades, because it seems like it would be a simpler mechanism for DNA replication than how it really works. But it doesn't seem to exist anywhere.

That sounds interesting. Would you be able to explain it a bit more?
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