They report that "neighborhoods" of 10 or 20 synapses "influence each other cooperatively," strengthening discrete groups of synapses.
What's more, this type of synaptic teamwork happens within a specific time-frame -- about 10 minutes, a perfect amount of time for laying down the kinds of memories that can lead to learning, Svoboda said.
"That's a very behavioral timescale for learning and memory," he said. For example, a mouse can be placed in a chamber, explore it for a few minutes, then be removed from the chamber and yet retain a working memory of that chamber once it has been reintroduced to it.
That's probably due to the fact that the mouse's brain formed synaptic clusters (i.e., memory) specific to the new chamber while it was exploring it, Svoboda explained.
"In this way, they can be dissociated [from the stimulus] over several minutes but still lead to learning," he said.
While many of these experiments were done in mice, the human brain should work similarly, albeit on a much larger scale, Svoboda said. While the mouse brain contains about 100 million neurons, human brains top out at a trillion such cells, he said.
And even though the research looked at healthy brain function, it may have implications for research into aging or diseased brains, as well.
"You need to understand the fundamental mechanisms. Then you can gain better insight into what might go wrong during neurodevelopmental and neurodegenerative disorders," Svoboda said.
"This work clearly shows us that all cells are important, and we should try and maintain and keep as many brain cells as possible," he said. "But the number is always flexible and, as you can see, even one cell can influence a number of others."
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