Lobes of Steel

Scientists have suspected for decades that exercise, particularly regular aerobic exercise, can affect the brain. But they could only speculate as to how. Now an expanding body of research shows that exercise can improve the performance of the brain by boosting memory and cognitive processing speed. Exercise can, in fact, create a stronger, faster brain

The Morris water maze is the rodent equivalent of an I.Q. test: mice are placed in a tank filled with water dyed an opaque color. Beneath a small area of the surface is a platform, which the mice can’t see. Despite what you’ve heard about rodents and sinking ships, mice hate water; those that blunder upon the platform climb onto it immediately. Scientists have long agreed that a mouse’s spatial memory can be inferred by how quickly the animal finds its way in subsequent dunkings. A “smart” mouse remembers the platform and swims right to it.

In the late 1990s, one group of mice at the Salk Institute for Biological Studies, near San Diego, blew away the others in the Morris maze. The difference between the smart mice and those that floundered? Exercise. The brainy mice had running wheels in their cages, and the others didn’t.

Scientists have suspected for decades that exercise, particularly regular aerobic exercise, can affect the brain. But they could only speculate as to how. Now an expanding body of research shows that exercise can improve the performance of the brain by boosting memory and cognitive processing speed. Exercise can, in fact, create a stronger, faster brain.

This theory emerged from those mouse studies at the Salk Institute. After conducting maze tests, the neuroscientist Fred H. Gage and his colleagues examined brain samples from the mice. Conventional wisdom had long held that animal (and human) brains weren’t malleable: after a brief window early in life, the brain could no longer grow or renew itself. The supply of neurons — the brain cells that enable us to think — was believed to be fixed almost from birth. As the cells died through aging, mental function declined. The damage couldn’t be staved off or repaired.

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Low-Cal Sweets Might Still Make Kids Obese

WEDNESDAY, Aug. 8 (HealthDay News) -- Diet foods and drinks meant to help children control their weight may actually spur overeating and obesity, Canadian researchers say.

The study found that animals learn to associate the taste of food with the amount of caloric energy it provides. The researchers speculate that children who eat low-calorie versions of foods that normally have a high calorie content may develop distorted connections between taste and calorie content, resulting in overeating as the children grow up.

"The use of diet food and drinks from an early age into adulthood may induce overeating and gradual weight gain through the taste conditioning process that we have described," lead author and sociologist Dr. David Pierce, of the University of Alberta, said in a prepared statement.

In a series of experiments published Aug. 8 in the journal Obesity, the researchers found that young rats started to overeat when they received low-calorie food and drink. Adolescent rats did not overeat when given low-calorie items.

This may be because, unlike the younger rats, the adolescent rats didn't rely on taste-related cues to assess the caloric energy content of their food, the researchers said.

"Based on what we've learned, it is better for children to eat healthy, well-balanced diets with sufficient calories for their daily activities rather than low-calorie snacks or meals," Pierce said.

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