How obesity may harm memory and learning

In obese mice, rogue immune cells chomp nerve cell connections

"Like people, mice that eat lots of fat quickly pack on pounds. After 12 weeks of a high-fat diet, mice weighed almost 40 percent more than mice fed standard chow. These obese mice showed signs of diminished brainpower, neuroscientist Elizabeth Gould of Princeton University and colleagues found. Obese mice were worse at escaping mazes and remembering an object’s location than mice of a normal weight.

On nerve cells, microscopic knobs called dendritic spines receive signals. Compared with normal-sized mice, obese mice had fewer dendritic spines in several parts of the mice’s hippocampi, brain structures important for learning and memory."