GRUMPY old people may be bad-tempered because their brains react differently to chronic stress. At least that’s what happens to elderly rats.
Elderly humans are more vulnerable to stress than their youthful counterparts. “There is more low-level anxiety and depression,” says of the University of Queensland in Brisbane, Australia.
To investigate why, Hirotaka Shoji of the in Obu, Japan, put 3-month-old and 24-month-old rats under stress by placing them inside a wire-mesh container for 1 hour every day for two weeks. Before this treatment began, the two sets of rats had…
