Each visual interface in the Brain Opera has been designed to allow participants and performers to compose, control and interpret Brain Opera music using their bodies in direct, intuitive, physical manipulations such as gesture, touch, and voice. These interfaces use evocative and poetic images instead of diagramatic or scientific indices to reflect and guide the participant's interaction with each system. The dominant visual metaphors of the Brain Opera are the body and the word. The body is a complex, dynamic network of sense perception and thought processing organs -- the physical manifestation of the multiple, distributed systems that induce and interpret perception, emotion and intellection. The word is the Minskian "agent" of language, a unit of meaning continuously evolving through contextualization, recombination and redefinition. The body is analogous to musical form, the word to music's content. Photographically-based images - rather than the computer graphics generally used for such interactive image systems - help to engage audience members by evoking memories and dreams, mystery and poetry, as well as accompaniment to every musical interaction.