Scientists have known for a long time that females react to infections differently than males, especially mood-wise. Researchers have been trying to figure out why. Now a new study shows that female mammals - rodents that is - react to the effects of an infection by producing more of a substance, called cytokines, in the brain yielding a “bad mood”–or a depressive-like behavior in a rat. The males did not suffer this effect.

Check out the University of Maryland study here.

Scientists at the Feinstein Institute for Medical Research have discovered how the immune system and the brain communicate to control disease. This is possible because the vagus nerve helps regulate the spleen, where immune cells and nerves interact. Read more in this release, which details the study that was originally published in the Proceedings of the National Academy of Sciences.