Fig. 2. Hypothetical depictions of within- versus between-subject variability as a function of brain state.

Each color (red, green, blue) is a subject, each of whom is measured in three different brain states (a, b, c). In the left panel, while states can push subjects around their personal “connectome space,” these spaces are non-overlapping. Thus, subject accounts for more of the variance than state, and subjects should always be perfectly identifiable. In the second scenario (right panel), the variance associated with state expands such that individual connectome spaces do overlap, and in some states a given subject might be mistaken for someone else (for example, subject 1 for subject 2 in state c).