Resting-state functional connectivity predictors of subjective visual Gestalt experience

Subjective perceptual experience is influenced not only by bottom-up sensory information and experience-based top-down processes, but also by an individuals current brain state. Specifically, a previous study found increased prestimulus insula and intraparietal sulcus (IPS) activity before participants perceived an illusory Gestalt (global) compared to the non-illusory (local) interpretation in a bistable stimulus. This study provided only a snapshot of the prestimulus brain state that favors an illusory interpretation. In the current study, we tested the hypothesis that the neural machinery that biases perception towards the illusory interpretation immediately before the stimulus onset, is also predictive of an individuals general tendency to perceive it, which remains stable over time. We examined individual differences in task-free functional connectivity of insula and IPS and related it to differences in the individuals duration of the two interpretations. We found stronger connectivity of the IPS with areas of the default mode and visual networks to predict shorter local perceptual phases, i.e., a faster switch to an illusory percept, but no equivalent results for the insula. Our findings suggest a crucial role of an IPS interaction with nodes of key intrinsic networks in forming a perceptual tendency towards illusory Gestalt perception.