O.Iris: The Mind's Eye Has an Iris — Mapping Brain State Dilation and Flexibility Through EEG Spectral Geometry

This preprint presents preliminary, exploratory findings from an open-source pipeline (O.Iris) that maps EEG-derived metrics onto a circular "pupil map" centered on a theoretically motivated focal value (spectral slope m ≈ 2.18). Across five independent publicly available EEG datasets (meditation, rest, sleep, working memory, stress; N > 36,000 windows), brain states occupy distinct positions in this geometric space. Meditation clusters nearest the focal value; sleep disperses furthest. We propose that mental health may correspond to flexibility of movement across this space rather than optimization toward any fixed position. All code and data pipelines are publicly available. This is exploratory preliminary work shared to invite replication and critique.