Thoughts and emotions can impact physiology. This connection is evident by the emergence of disease following stress or recovery in response to placebo treatment. Nevertheless, this fundamental aspect of physiology remains largely unexplored. By combining state of the art tools in neuroscience and in immunology we aim to uncover how specific brain activity affects the immune system and the organism’s response to cancer. In this talk, I will focus on the brain’s involvement in regulating the peripheral immune responses and share our new findings on how the immune system is perceived and represented in the brain.