The Brain That Changes Itself (2007)
By Norman Doidge
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The same applies to mobility. Just doing the dances you learned years ago won’t help your brain’s motor cortex stay in shape. To keep the mind alive requires learning something truly new with intense focus. That is what will allow you to both lay down new memories and have a system that can easily access and preserve the older ones.
The thirty-six scientists at Posit Science are working on five areas that tend to fall apart as we age. The key in developing exercises is to give the brain the right stimuli, in the right order, with the right timing to drive plastic change. Part of the scientific challenge is to find the most efficient way to train the brain, by finding mental functions to train that apply to real life.
Merzenich told me, “Everything that you can see happen in a young brain can happen in an older brain.” The only requirement is that the person must have enough of a reward, or punishment, to keep paying attention through what might otherwise be a boring training session. If so, he says, “the changes can be every bit as great as the changes in a newborn.”
Posit Science has exercises for memory of words and language, using Fast ForWord–like listening exercises and computer games for auditory memory designed for adults. Instead of giving people with fading memories lists of words to memorize, as many self-help books recommend, these exercises rebuild the brain’s basic ability to process sound, by getting people to listen to slowed, refined speech sounds. Merzenich doesn’t believe you can improve a fading memory by asking people to do what they can’t. “We don’t want to kick a dead horse with training,” he says. Adults do exercises that refine their ability to hear in a way they haven’t since they were in the crib trying to separate out Mother’s voice from background noise. The exercises increase processing speed and make basic signals stronger, sharper, and more accurate, while stimulating the brain to produce the dopamine and acetylcholine.
Various universities are now testing the memory exercises, using standardized tests of memory, and Posit Science has published its first control study in the Proceedings of the National Academy of Sciences, USA. Adults between the ages of sixty and eighty-seven trained on the auditory memory program an hour a day, five days a week, for eight to ten weeks—a total of forty to fifty hours of exercises. Before the training, the subjects functioned on average like typical seventy-year-olds on standard memory tests. After, they functioned like people in the broad forty-to-sixty-year-old range. Thus, many turned back their memory clock ten or more years, and some individuals turned it back about twenty-five years. These improvements held at a three-month follow-up. A group at the University of California at Berkeley, led by William Jagust, did “before” and “after” PET (positron emission tomography) scans of people who underwent the training, and found that their brains did not show the signs of “metabolic decline”—neurons gradually becoming less active—typically seen in people of their age. The study also compared seventy-one-year-old subjects who used the auditory memory program with those of the same age who spent the same amount of time reading newspapers, listening to audiobooks, or playing computer games. Those who didn’t use the program showed signs of continuing metabolic decline in their frontal lobes, while those who used it didn’t. Rather, program users showed increased metabolic activity in their right parietal lobes and in a number of other brain areas, which correlated with their better performance on memory and attention tests. These studies show that brain exercises not only slow age-related cognitive decline but can lead to improved functioning. And keep in mind that these changes were seen with only forty to fifty hours of brain exercise; it may be that with more work, greater change is possible.
Merzenich says they have been able to turn back the clock on people’s cognitive functioning so that their memories, problem-solving abilities, and language skills are more youthful again. “We’ve driven people to abilities that apply to a much more youthful person—twenty or thirty years of reversal. An eighty-year-old is acting, operationally, like they are fifty or sixty years old.” These exercises are now available in thirty independent-living communities and for individuals through the Posit Science Web site.
Posit Science is also working on visual processing. As we age, we stop seeing clearly, not just because our eyes fail but because the vision processors in the brain weaken. The elderly are more easily distracted and more prone to lose control of their “visual attention.” Posit Science is developing computer exercises to keep people on task and speed up visual processing by asking subjects to search for various objects on a computer screen.
There are exercises for the frontal lobes that support our “executive functions” such as focusing on goals, extracting themes from what we perceive, and making decisions. These exercises are also designed to help people categorize things, follow complex instructions, and strengthen associative memory, which helps put people, places, and things into context.
Posit Science is also working on fine motor control. As we age, many of us give up on tasks such as drawing, knitting, playing musical instruments, or woodworking because we can’t control the fine movements in our hands. These exercises, now being developed, will make fading hand maps in the brain more precise.
Finally, they are working on “gross motor control,” a function that declines as we age, leading to loss of balance, the tendency to fall, and difficulties with mobility. Aside from the failure of vestibular processing, this decline is caused by the decrease in sensory feedback from our feet. According to Merzenich, shoes, worn for decades, limit the sensory feedback from our feet to our brain. If we went barefoot, our brains would receive many different kinds of input as we went over uneven surfaces. Shoes are a relatively flat platform that spreads out the stimuli, and the surfaces we walk on are increasingly artificial and perfectly flat. This leads us to dedifferentiate the maps for the soles of our feet and limit how touch guides our foot control. Then we may start to use canes, walkers, or crutches or rely on other senses to steady ourselves. By resorting to these compensations instead of exercising our failing brain systems, we hasten their decline.
As we age, we want to look down at our feet while walking down stairs or on slightly challenging terrain, because we’re not getting much information from our feet. As Merzenich escorted his mother-in-law down the stairs of the villa, he urged her to stop looking down and start feeling her way, so that she would maintain, and develop, the sensory map for her foot, rather than letting it waste away.
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