The dynamic bodily self across lifespan: Agency, ownership, and the plasticity of internal body models.

Two fundamental aspects of research on bodily self-consciousness, agency and body ownership, have recently seen exponential growth. The seminal paper of Botvinick and Cohen in 1998 provided a vital psychophysical tool for studying the bodily self - the rubber hand illusion, in which one feels as if an external object becomes a part of one's body. Recent motor control views of ownership highlight the influence of agency, the sense that one is in control of one's movements. Technological advancements have facilitated more ecologically valid experimental paradigms, such as virtual versions of the rubber hand illusion, furthering our understanding of the mechanisms through which the brain generates agency and ownership sensations. Recent findings suggest that agency and ownership can interact while remaining dissociable, as one may experience agency over an object that is not embodied or ownership of an object that cannot be controlled. Understanding the neurocognitive mechanisms underlying agency and ownership is critical for addressing the challenges of healthy aging. As sensory-motor precision declines across the lifespan, maintaining a coherent sense of body and control becomes essential for mobility, the successful adoption of assistive technologies, and overall cognitive resilience. This review synthesizes current findings on the agency-ownership interaction, discusses its neurobiological substrates, and explores its transformative potential for the design of "self-inclusive" prosthetics and brain-machine interfaces. We conclude by outlining a framework showing how optimization of these processes can support functional independence and psychological well-being in an aging population.