Stressed out. A little stress might be good for you, but too much, and you won’t operate at peak capacity, says a study on the effect of stress on the brain, from New York’s Weill Medical College at Cornell and Rockefeller University, published in the journal Proceedings of the National Academy of Sciences. For the study, 20 medical students about to take board exams — all of them stressed — were examined via functional MRI, which measures flow of blood in the brain. Researchers compared the performance and brain function of the medical students with a group of similarly aged subjects who were not stressed. When put to two tasks that measured the ability to shift attention and then shift back, the medical students performed far worse than the relaxed group. During the attention-shifting task, activity in the stressed group’s prefrontal cortices — the seat of such functions as attention, task-planning and judgment — was far lower than that of the nonstressed. A month after the exams were over, the med students repeated the tasks and their brain scans looked similar to those of the control group. Los Angeles Times
