Behaviors such as eating, exercise, and sleep significantly impact the body's health, and vice versa; the state of bodily health can also affect the performance of these behaviors. For example, appropriate dieting helps relieve body inflammation, while bacterial or viral infections can lead to sickness behaviors, including decreased appetite, reduced physical activity, and lethargy. 

The nervous system plays essential roles in regulating eating, exercise, and sleep, and recent research has revealed multiple neural circuits involved in regulating these innate behaviors. Additionally, there exists a close interaction between the nervous and immune systems. 

Therefore, the nervous system may act as a bridge between behavior and bodily health. From a systems neurobiology perspective, studying the interactions between the nervous system, behavior, and immune system will help us gain a deeper understanding of the body's operation as a whole.