memory

Marijuana, it seems, is not a performance-enhancing drug. That is, at least, not among young people, and not when the activity is learning.

A little electrical brain stimulation can go a long way in boosting memory.

The key is to deliver a tiny pulse of electricity to exactly the right place at exactly the right moment, a team reports in Tuesday's Nature Communications.

"We saw a 15 percent improvement in memory," says Michael Kahana, a professor of psychology at the University of Pennsylvania and an author of the study.

Decades ago, scientists surgically attached pairs of rats to each other and noticed that old rats tended to live longer if they shared a bloodstream with young rats.

It was the beginning of a peculiar and ambitious scientific endeavor to understand how certain materials from young bodies, when transplanted into older ones, can sometimes improve or rejuvenate them.

Brain training is big business, with computerized brain games touted as a way to help prevent memory loss. But new research shows you might be better off picking up a challenging new hobby.

To test this theory, Dr. Denise Park, a neuroscientist at the University of Texas at Dallas, randomly assigned 200 older people to different activities. Some learned digital photography. Another group took up quilting.