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Neuronal Learning Observed
Gregg Favalora writes "According to this week's EE Times, R. Colin Johnson reports that researchers at UC San Diego have directly observed the physical changes that neurons undergo during learning.
His article explains that neurons were cultured on a smooth, photoconductive silion substrate. Using optical techniques, they were able to trigger individual neurons into firing -- and were actually able to observe some of the physical changes that underly short- and long-term learning.
According to the article, "[The team] tested out the theory that learning results from a physical change that strengthens the connections between selected neurons. [They showed] how short- and long-term memories result from different physical effects in the brain. Short-term memories, it turns out, result from the instant assembly of more filaments to strengthen the skin of the cell temporarily, whereas long-term memories result from the growing of a new synapse to strengthen the connection permanently."
Besides the interesting cellular observations they're making, I am also intrigued by the process the article describes which uses properties of the silicon substrate to aid in firing individual neurons. "
I know, I know, why not a human. I start getting all ethical when I think of that.
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This would be interesting to see. In The Natural Mind, Dr. Andrew Weil elaborates on his 1960's Harvard research which showed that short-term recall and task performance were dependent on whether the task/info was learned while the subject was in the same state of mind for the testing (learned stoned, performed straight; learned stoned, performed stoned; ...). Emperical evidence illustrated that difficulty in short-term recall was a product of the subject's anxiety about being stoned in a test situation.
But let's see some biology in action and the physical results. Don't get your hopes up, though: Presidents Nixon and Reagan declared drug wars despite the findings of scientists they commissioned to study the effects of illegal drug usage on society.
"What is the sound of one belly slapping?"
Here is a link to the lab's home page. The project is described briefly here. It would be nice if web-based included those links. It would also be nice if people in the biological sciences followed CS and put their publications on-line.
For more background info on how neurons work: see How stuff works sub-page on the brain. I was hoping that they would have a good discussion on how sodium and potasium ions move through the cell membranes creating a charge, but at least it's a good intro.
Kind thoughts do not change the world
forma3
[The team] tested out the theory that learning results from a physical change that strengthens the connections between selected neurons. [They showed] how short- and long-term memories result from different physical effects in the brain
They showed physical effects that MAY be responsible for the phenomenon that we call memory. This is very good work, and it shows that these physical effects occur in the brain (there is some possibility that it's an artifact of their method but it's pretty slim.) They also occur on about the right timescale to explain memory. HOWEVER that is NOT sufficient to show that these physical effects are responsible for the phenomenon we call memory, just that they very well could be.
The point at which you call something "proven" can be fairly subjective but in this case we haven't eliminated other potential physical effects that might play some role, possibly a crucial or pivotal one, in actual memory.
As a scientist, I am convinced (just short of certain) that the effects that they've observed play some role in real memory. That doesn't mean that they play the definitive role.
I suspect that the scientists responsible for the research couched there statements in a number of caveats that the reporter simply ignored.
The good and new comes from no quarter where it is looked for, and is always something different from what is expected.
It's very cool to read that the basic research to verify neural models is being done. Like someone else said, it's not definitive, but it certainly does give us good evidence that certain electro-chemical situations strengthen existing synapses and even form new ones (the filaments).
I've always felt (intuitively, not scientifically) that the brain was made up of a series of interconnected networks, each fulfilling different roles. There's a very special role, though -- our point of interest.
If synapses are altered by the current that flows through them, then point of interest is critically important because it directs where the current goes.
The upshot is that the things you find interesting (and think about) are the things that get strengthened. So what determines your interest?
Well, we're very visual creatures, so a lot of what interests us is stuff we can see. We are continually interested in a great deal of the information that comes in from our five senses.
This sort of implies that you can strengthen different points of your mind by focusing on them, directing your interest towards those points. Your interest excites those neural pathways in your mind, strengthening them.
Want to get better at programming? THINK about it. A lot. Stop thinking about what you're seeing, and move in an abstract direction instead. Don't waste your valuable brain electricity on strengthening visual neurons that take too much already.