Exercising our minds isn’t just a cliché, now it’s a mantra we should all live by if we want to keep fresh neurons, thousands of which are generated each day, alive. Recent research with rats shows that learning enhances the survival of new neurons in the adult brain, specifically in the hippocampus area of the brain. Moreover, the more challenging the problem, the more cells that survive. This research continues to build upon findings from work done in the 1990s by Elizabeth Gould, which showed that the mature mammalian brain was able to grow new neurons, a process called neurogenesis. Scientists had long believed that only young developing minds were able to perform this critical function.
While exercising the brain through learning can keep neurons alive, those new cells don’t survive indefinitely. In fact, most disappear after just a few weeks. From its work with rats, Dr. Tracey J. Shors, professor in the Department of Psychology and Center for Collaborative Neuroscience at Rutgers University, and her team believe that the cells are made “just in case.” “If the animals are cognitively challenged, the cells will linger. If not, they will fade away. Gould, who is now at Princeton University, and I made this discovery in 1999, when we performed a series of experiments looking at the effect of learning on the survival of newborn neurons in the hippocampus of rat brains,” writes Dr. Shors in the March 2009 issue of Scientific American. Dr. Shors and her team used a learning task called trace eyeblink conditioning in which a rat hears a tone and a half second later, receives a puff on its eyelid, causing it to blink. After several hundred trials, the animal usually makes a mental connection and blinks before receiving the stimulation. This provides a good way to measure “anticipatory learning,” which is the ability to predict the future based upon the past, writes Dr. Shors.
The scientists conducted additional studies to determine which types of learning work. They found that those tasks which required the most mental effort to master rescued the greatest number of new neurons from death. Click below to read the full column by Dr. Shors.
Column: How to save new brain cells by Tracey Shors www.sciam.com March 2009
