Men lose brain tissue as they age at almost three times the rate women do; this could reduce their memory, concentration and reasoning power, says Ruben C Gur, a professor of psychology at the University of Pennsylvania, US. His findings are based on a study of the brain functions -measurement of volume and analysis of metabolic rates within the organ -in 24 women and 37 men over the past decade. "The shrinking size of brains in men, perhaps, turns them into grumpy old men," he opines. Some of the tissue loss, according to Gur, is in the left frontal lobe of the brain, which is apparently connected to depression.