Buff Your Brain Ⅲ

    EEGs, electrodes that record brain activity, suggest how that happened. The number of bursts of electrical activity called sleep spindles—Walker calls them “champagne pops in the brain”—that people experienced during their naps predicted how much their ability to learn would improve once they awoke. Sleep spindles, he suspects, indicate activity in the hippocampus that moves information from that region into the cortex for permanent storage. It’s like moving data from a USB stick onto a hard drive, which “both consolidates into long-term storage the information you offload and leaves you a renewed capacity for absorbing new information—learning,” says Walker. The better we move information from the hippocampus (working memory) into the cortex, the more information we can access when we need it.

    Even without the midday nap, the brain has a way of carving out its own downtime, characterized by what’s called the “default-mode network”—basically, brain activity that takes place when you’re daydreaming or keeping your mind blank. Using functional MRI, scientists at Japan’s Tohoku University measured cerebral blood flow in 63 volunteers asked to keep their minds blank. Those with the greatest blood flow in the white matter that connects one neuron to another scored highest on a task requiring them to quickly generate novel ideas, the researchers reported in the journalPLoS One in November. Creativity arises from seeing connections others miss, so it makes sense that increasing the activity in white matter by letting the brain rest in default mode supports creativity. So put away the BlackBerry and let your brain idle.

    Too hyper to do that? Then go all in with a jolt of caffeine. It might not make you more creative, but coffee can make your mind sharper, as zillions of java addicts will swear. A 2011 study inNature Neuroscience backs them up: in lab rodents, caffeine strengthens brain connections. Rats given shots of joe comparable to two cups of coffee had stronger electrical activity between neurons in the part of the hippocampus called CA2 than they did otherwise, found Serena Dudek of the National Institute of Environmental Health Sciences and colleagues. Stronger connectivity means better learning and memory.

    For more exalted cognitive functions, the strategy with the strongest evidence behind it is also the toughest: learn a second language. When a brain that is fluent in two languages chooses between, say, English and French, the cortical circuits that hold both languages become active. The prefrontal cortex must then step in to choose the right word—man orhomme?—for the circumstances. The prefrontal is also the site of those higher-order functions. The workout it gets in bilingualism carries over, buffing such IQ-building skills as problem solving and attention switching, finds cognitive scientist Ellen Bialystok of Canada’s York University. That workout seems to postpone dementia by five years, she and colleagues reported last February.

    Brain exercise, not to mention becoming bilingual, takes time, so naturally everyone wants to believe certain foods increase intelligence. After all, eating is easy! But a 2010 analysis of hundreds of studies, done by researchers at the Duke Evidence-Based Practice Center, found that many highly touted recipes for cognitive enhancement are a bust. Supplements containing vitamins B6, B12, or E, or folic acid, did nothing to preserve cognitive function, let alone enhance it. The evidence is hardly better for the fish-, fruit-, vegetable-, and olive-oil-rich Mediterranean diet. Overall, there is not yet rigorous proof that foods high in antioxidants or flavonoids enhance intelligence, but scientists have hopes for a number of exotic foods and ingredients. For instance, some small studies suggest that turmeric, a spice common in Indian cooking, and pomegranate juice may improve memory or other aspects of cognitive function.

    But that still leaves you with a brain-buffing trifecta. Memory training fueled by caffeine and interspersed with good sleep and aerobic conditioning, computer-based brain exercises to hone attention, and a regimen of reading, watching, and doing broken up by ample mental downtime: it promises to add up to a smarter you in 2012 and beyond.