Subjectivity defines the subject who is perceiving, feeling, thinking, acting, and is essential to understand the conscious mind from the inside. In its simplest form, subjectivity is the first-person perspective inherent to conscious mental life. The BRAVIUS project proposes a biological mechanism to generate first-person perspective and tests it experimentally. Two vital organs that generate their own rhythmic electrical activity, the stomach and the heart, constantly send information up to the neocortex, even in the absence of bodily change. Cortical responses to those visceral organs would define the organism as an entity at the neural level, and create a subject-centered reference frame from which first-person perspective can develop. The results of the BRAVIUS project are important to understand the nature of human consciousness, but also to offer experimental tools to probe for the existence of consciousness in non-communicating patients. In a more distant future, the framework developed in BRAVIUS might prove important to probe for consciousness in animals or artificial-intelligence based systems.