A string of scientists prove that the brain and immune system can talk to each other. They show that hormones and molecules released by the nervous system can affect the immune system and vice versa. Prior to this research, it was believed that the brain and immune system could not communicate directly.

In 1975, neuroendocrinologist Hugo Besedovsky shows that activation of the body’s immune response also increases stress hormones in the blood. In 1984, immunologists Adriano Fontana and Jean-Michel Dayer show that the brain makes immune molecules when the body is exposed to bits and pieces of bacteria. Also in 1984, neuroanatomists David and Suzanne Felten and Karen Bulloch show that immune organs like the spleen contain a rich network of adrenalin-like nerves that affect immune cell function. In 1987, three teams of neuroendocrinologists led by Robert Sapolksy; Frank Berkenbosch and Hugo Besedovsky and Edward Bernton prove that an immune molecule called interleukin-1 stimulates nerve cells as well as the brain’s stress center. In that same year, neuroscientists Candace Pert and Henry Arimura show that the brain has receptor sites for these very immune molecules.