Your Brain Creates New Cells When Learning and Then Kills Them
Each time you learn a skill, new cells burst into life in your brain. Then one by one those cells die off since your mind figures out which ones it needs.
Journal Trends in Cognitive Sciences published online on Nov. 14 a research that proposed that this swelling and shrinking of the mind is a Darwinian process.
An initial burst of cells helps the brain cope with information, according to the paper. The mind works out which are unnecessary, killing the extras off at a survival-of-the-fittest contest and which operate best. That cull leaves the tissues that the mind needs to most effectively maintain what it has learned, the paper said.
The primary swelling is "somewhat modest, naturally," said lead author Elisabeth Wenger, a researcher in the Center for Lifespan Psychology in the Max Planck Institute for Human Development in Berlin, Germany. "It would be quite impractical to have enormous changes" within the skull.
Scientists have long known that brains vary in reaction. A classic 2003 study, for example, observed major volume differences between the brains of amateur and professional musicians. But the study is the first time researchers have watched that expansion provided a theory, also in activity over a rather long timescale, Wenger said.
Her coworkers and Wenger had 15 study subjects that are right-handed learn to write with their left hands-on. The researchers exposed the enterprising students to magnetic resonance imaging (MRI) brain scans over the analysis period. The grey matter from the subjects' motor cortices (areas of the brain involved in muscular movement) grew by an extra 2 to 3 percent before shrinking back into its initial dimensions, the investigators found.
"It's so tough to observe and discover these volumetric adjustments, because, as you can imagine, there are also many sound factors that come into play when we measure ordinary participants in the MRI scanner," Wenger told Live Science. ("Noise" refers to messy, fuzzy artifacts in data that make it hard for researchers to make precise measurements.)
MRIs use physics to peer pressure through the walls of the skull. But the machines aren't perfect and can introduce errors in measurements that are fine. Along with the human brain shrinks and swells for reasons Wenger said. As an example, your brain is turgid and a lot thicker after a couple of glasses of water than if you're dehydrated, Wenger said.
That is why it's taken so long for investigators to make good observations of this growth and to shrink over time (or, as the scientists call it, expansion and renormalization), '' Wenger said. It is also why they can't yet offer more detail as to exactly which cells expiring off to induce that change and are multiplying, she said.
Some mix of synapses and neurons -- as well as many other cells that help the brain work -- bursts into being as the brain learns. And a number of those cells disappear.
That's all of the investigators know so far, though it's enough for them to develop their model of renormalization and growth. To deeply understand what kind of cells have been selected for, and how the process works, the investigators will need to study the procedure at a finer degree of detail, '' they stated in the paper. They need to see which cells are currently emerging and which are evaporating.
In trying to do that researcher face the challenge of neuroscience: It is not ethical to slice into the skulls of people that are living and poke around with needles and microscopes.
Wenger stated the upcoming steps would involve fine-tuning MRIs to help to provide the finer level of detail the scientists want. The investigators will also do some poking around in the minds of animals, in which growth and renormalization are already, '' she added.
