• Posted: Jun 12, 2014 11:29:46
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Per an article posted Sunday by the BBC, scientists in China and the U.S. have now observed the mechanism by which learning is consolidated during sleep by the physical growth of new synapses, connections between brain cells. Using microscopy, researchers at New York University and Peking University observed the brains of mice during sleep. While awake, attempts were made to teach the mice a new trick, walking on a spinning rod. Mice allowed undisturbed normal deep sleep learned the task more readily than mice whose sleep was disturbed. The observed difference between the two sets of mice were the numbers of new neuronal synapses formed during sleep. What the scientist believe happened was that during slow wave deep sleep, the mouse brains were "replaying" temporary memories from their day while, at the same time, cell mechanisms were being turned on that promote the learning or "fixing" of knowledge from those memories within new more permanent networks of connections amongst brain cells via the growth of new synapses. Synapses, of course, are the tips of fingers on the ends of cell dendritic extensions that excrete neurotransmitters like serotonin and dopamine, chemicals that make transient connection between two or more cells, allowing them to communicate. The researchers concluded that if such processes were interrupted, as in the mice whose sleep cycles were disturbed, learning was also interrupted. The practical implication is that undisturbed sleep is important for learning.
Their discovery recalls and seems to validate something I wrote many years ago, which seemed self-evident to me at the time, and which I presented to a forum on dreaming. Back then, my thoughts were received with great skepticism, not unlike what is happening in the picture above. I will not now include those thoughts, but consider what seems to be happening during dreaming, and relatedly within remembering, thinking, and imagining. During sleep, we are overwhelmingly passive, like relaxing before a movie. Our brains sort through temporarily held memories of things from our days, trying to relate and connect them to more substantial networks of knowledge we already possess, apparently via mechanisms observed above. Within that process, fleeting novel connections are made, which we see in dreams as novel sequences of images. For the most part, we passively experience that undirected process as mildly amusing. But sometimes, we find those sequences of images disturbing. And, we wake in agitation.
Now consider thinking and imagining, day dreaming if you will. What we experience by day seems quite similar to what we experience during sleep, a series of novel juxtapositions of images and remembrances. But for at least some of us, the awake process is not entirely passive. We can willfully direct the course such novel sequences take, first including this and then that, rearranging that thing and then this. In other words, some locus within our brains is adept at exercising willful control over other more passively experienced cascades of processes within our brains. So, where is that locus of control? How does it work? And, why do some folks seem to lose control of those subsequent cascades of images, as in PTSD and schizophrenia? And then again, why do many of us have some control, but then the subsequent cascades peter out early and our imaginations fail to make insightful connections? Dim bulbs, we may be called.
I suspect the above research and researches to follow will eventually offer answers to those intriguing questions. One hopes so, at least.
Saturday, June 9th, 2012
30.7 mm 145 mm