Using bistable stimuli we can investigate the neural processes underlying our subjective perception. Previous studies found that illusory Gestalt perception is accompanied by activity in the superior parietal lobe. In this study, we used fMRI to investigate brain activity prior to the formation of an illusory Gestalt. For this reason we presented 31 study subjects with global motation stimuli which could be viewed either global or local. Compared to the local intepretation of the stimulus the global interpretation was accompanied by increased activity in the intraparietal sulcus (IPS) and the putamen. Perhaps the most interesting finding in this study was increased bilateral activity in the dorsal insula, which preceded the global stimulus. Thus, the insula, which processes saliency and provides conscious access to information, plays an important role in illusory Gestalt perception.
Source: Wilding, M., Körner, C., Ischebeck, A., & Zaretskaya, N. (2022). Increased insula activity precedes the formation of subjective Gestalt. Neuroimage, 257, 119289. doi.org/10.1016/j.neuroimage.2022.119289