Commentary: Is the Frontal Lobe Involved in Conscious Perception?

Like any other field, the field of consciousness research benefits from a careful distinction between the concepts involved. An example is the distinction between the state of being conscious (e.g., whether someone is awake) and the contents of consciousness (e.g., whether someone perceives a dress as white or blue). A similar type of distinction can contribute to the resolution of a debate regarding the role of the frontal cortex in conscious perception. In a recent publication Safavi et al. (2014) responded to conclusions drawn in a study regarding the role of frontal cortex in conscious perception. This study, by Frässle et al. (2014), employed binocular rivalry to show that well-established frontal BOLD correlates of perceptual switches (Lumer et al., 1998; Sterzer and Kleinschmidt, 2007) were strongly diminished when participants passively viewed these switches rather than reporting them. Frässle and co-workers (among whom the present paper's first author) concluded: " frontal areas are associated with active report and introspection rather than with rivalry per se. " This statement is a bit audacious, as it rules out any role of frontal areas in rivalry other than their role in reporting perception. As such, Safavi and co-workers draw into question this conclusion, based on evidence indicating that neural activity in frontal areas, in particular in the lateral prefrontal cortex, reflects the contents of consciousness in paradigms that do not involve active report. Here we aim to bring these two positions closer together by making an explicit distinction between neural activity that reflects the content of consciousness, and neural activity that brings about changes in consciousness during perceptual bistability. Safavi et al. (2014) bring forward a variety of studies linking frontal lobe function to the content of consciousness (Imamoglu et al., 2012; Panagiotaropoulos et al., 2012). Frässle and colleagues, in turn, are specifically concerned with fMRI BOLD responses that are time-locked to perceptual switches, not to periods when the contents of consciousness are stable. Recent debate has focused on the question what brings about this switch-related BOLD signal during bi-stable perception, with a central question being whether it reflects a neural initiation of these switches or an indirect consequence (Sterzer et al. Frässle and colleagues' conclusions should be understood in the context of this question. Specifically, the conclusions promote the idea that the frontal response observed during binocular rivalry reflects an indirect consequence of perceptual switches, as it is associated with reporting them. In …