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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. "
It's the human brain's ablility to recognise patterns and small details in complex systems that seems to allow it to remember so much. It is only in fact, remembering a concept from a book or the outline of an object. Many test have been done to show that the human brain actually remembers very little of it's surroundings. Most of it is just filtered out as noise.
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.
forma3
The chip preparation seems cool, but this experiment doesn't prove a thing about learning or memory.
Changes in individual neurons have been observed in many ways (electrically, visually) in many preparations (live animals, brain slices, brain cultures) in response to artificially induced activity like what these guys used.
The problem is the assertion that the artificially induced activity is anything like what happens during real learning in an intact, awake brain. This is a hard problem, and the present study doesn't address it at all.
The study therefore has no real relevance to learning and memory.