'Braindrops' is an interactive, audio-visual performance in the no-man's-land between an and science. A psycho-physical interface makes changes in the recipient's condition immediately visible and audible. The subjective is made objective as self-discovery in the form of images and sounds. The installation makes spatial-temporal patterns of the impact of raindrops falling on various sound-making surfaces, creating a complex multitude of auto-generated sound and light structures. Various psycho-physiological signals of the subject (EEG, EMG,...) are measured using sensors and correlated. Changes in the individual's psycho-physical state are thereby fed back into the audio-visual event itself (biofeedback). This constitutes an instrument to reify and experientialize our theory; a model for regulating impression and expression, an aesthetic possibility to project and communicate visible and audible metaphors of one's own consciousness.