 Using this paradigm, researchers have found neuronal changes both in early visual areas and in later areas, as well as changes in widespread neuronal synchrony, that correspond temporally with subjective reports of flipping between one way and another of seeing the ambiguous figure (Kleinschmidt et al. 1998; Rodriguez et al. 1999; Ilg et al. 2008; Parkkonen et al. 2008; de Graaf et al. 2011; Megumi, Bahrami, Kanai, and Rees 2015; Brascamp, Sterzer, Blake, and Knapen 2017). In masking paradigms, stimuli are briefly presented then followed by a “mask”. On some trials, participants report seeing the stimuli, while on others they don’t. In trials in which the participant reports that stimulus was visually experienced, researchers have tended to find higher levels of activity through at least some of the downstream visual pathways as well as spontaneous electrical oscillations near 40 Hz (Dehaene et al. 2001; Summerfield, Jack, and Burgess 2002; Del Cul, Baillet, and Dehaene 2007; Quiroga et al. 2008; Salti et al. 2015). However, it remains contentious how properly to interpret such attempts to find neural correlates of consciousness (Noë and Thompson 2004; Overgaard, Sandberg, and Jensen 2008; Dehaene and Changeux 2011; Aru, Bachmann, Singer, and Melloni 2012; de Graaf, Hsieh, and Sack 2012; Koch et al. 2016; Phillips 2018).