It’s pretty clear that exercise in general aids brain function. Still, it is interesting to see a recent finding that resistance training (which includes weightlifting) in particular seems to help the cognitive function of older women who were beginning to show cognitive decline.
You can read about the study at Science Daily or ready the study itself on strength training and memory at the Archives of Internal Medicine. The study claims to be the first to compare the benefits of aerobic versus resistance training on mental function needed for independent living. In this study, at least, resistance training wins.