Newsweek looks at the work and studies related to building better brains. Neuroscientists are discovering the mechanisms of intelligence, they are identifying what really works.
The quest for effective ways to boost cognitive capacity is not hopeless, however. The explosion in neuroscience is slowly revealing the mechanisms of cognition. “We have accumulated enough knowledge about the mechanisms and molecular underpinnings of cognitionat the synaptic and circuit levels to say something about which processes contribute,” says James Bibb of the University of Texas Southwestern Medical Center, who organized a symposium on “cognitive enhancement strategies” at the 2010 meeting of the Society for Neuroscience. Greater cognitive capacity comes from having more neurons or synapses, higher levels of neurogenesis (the creation of new neurons, especially in the memory-forming hippocampus), and increased production of compounds such as BDNF (brain-derived neurotrophic factor), which stimulates the production of neurons and synapses, says neuroscientist Yaakov Stern of Columbia University. Both neurogenesis and synapse formation boost learning, memory, reasoning, and creativity. And in people who excel at particular tasks, Stern’s neuro-imaging studies show, brain circuits tend to be more efficient (using less energy even as cognitive demand increases), higher capacity, and more flexible.
A rule of neuroscience is that “neurons that fire together, wire together” suggests that cognitive training should boost mental prowess. Studies are finding just that, but with a crucial caveat. Training your memory, reasoning, or speed of processing improves that skill, found a large government-sponsored study called Active. Unfortunately, there is no transfer: improving processing speed does not improve memory, and improving memory does not improve reasoning.
The holy grail of brain training is something that does transfer, and here there are three good candidates.
1. The first is physical exercise. Simple aerobic exercise, such as walking 45 minutes a day three times a week, improves episodic memory and executive-control functions by about 20 percent, finds Art Kramer of the University of Illinois at Urbana-Champaign.
2. The second form of overall mental training is meditation, which can increase the thickness of regions that control attention and process sensory signals from the outside world. In a program that neuroscientist Amishi Jha of the University of Miami calls mindfulness-based mind-fitness training, participants build concentration by focusing on one object, such as a particular body sensation. The training, she says, has shown success in enhancing mental agility and attention “by changing brain structure and function so that brain processes are more efficient,” the quality associated with higher intelligence.
3. Finally, some videogames might improve general mental agility. Stern has trained older adults to play a complex computer-based action game called Space Fortress, which requires players to shoot missiles and destroy the fortress while protecting their spaceship against missiles and mines. “It requires motor control, visual search, working memory, long-term memory, and decision making,” he says. It also requires that elixir of neuroplasticity: attention, specifically the ability to control and switch attention among different tasks. “People get better on tests of memory, motor speed, visual-spatial skills, and tasks requiring cognitive flexibility,” says Stern. Kramer, too, finds that the strategy-heavy videogame Rise of Nations improves executive-control functions such as task switching, working memory, visual short-term memory, and reasoning in older adults.
By nailing down the underpinnings of cognition, neuroscientists can separate plausible brain boosters from dubious ones. With apologies to the political-correctness police, nicotine enhances attention—that key driver of neuroplasticity—and cognitive performance in both smokers and nonsmokers, scientists at the National Institute on Drug Abuse reported in a 2010 analysis of 41 double-blind, placebo-controlled studies. Nicotine, they found, has “significant positive effects” on fine motor skills, the accuracy of short-term memory, some forms of attention, and working memory, among other basic cognitive skills. The improvements “likely represent true performance enhancement” and “beneficial cognitive effects.” The reason is that nicotine binds to the brain receptors for the neurotransmitter acetylcholine that are central players in cortical circuits. (Caveat: smoking also increases your risk of dementia, so while cigarettes may boost your memory and attention now, you could pay for it later. To be determined: whether a nicotine patch delivers the benefits without the risks.
Neuroscience supports the cognitive benefits of stimulants like Adderall and Ritalin, too, at least in some people for some tasks. Both drugs (as well as caffeine) raise the brain levels of dopamine, the juice that produces motivation and the feeling of reward. On balance, finds psychologist Martha Farah of the University of Pennsylvania, studies show that both drugs enhance the recall of memorized words as well as working memory (the brain’s scratchpad, which plays a key role in fluid intelligence). They do not improve verbal fluency, reasoning, or abstract thought, however, nor provide much benefit to people with a gene variant that keeps dopamine activity high, Farah found in a recent study.
These limitations suggest two things. First, if you’re naturally awash in dopamine and are highly motivated to, say, deduce from its source code how a website was built, then increasing dopamine levels pharmacologically is unlikely to help. Farah found no difference between the performance of volunteers given Adderall and volunteers given a placebo on a battery of cognitive tasks, suggesting that you can get the same dopamine-boosting benefits of the drug by simply believing that you’ll do well, which itself releases dopamine. Second, the divide between the mental functions that drugs do and don’t improve suggests that psychological factors such as motivation and reward help with memory, but not higher-order processes such as abstract thought. The drugs “will help some people some of the time, but maybe not by a whole lot,” she concludes.
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