Understanding how consciousness arises from neural activity in the human brain remains one of the greatest scientific challenges of modern times (Crick, 1994). Phenomenologically, consciousness has been defined as subjective experience, or what it is like to perceive, feel, or think from a first-person perspective (Chalmers, 1998). Scientifically, the neural correlates of consciousness (NCCs) have been defined as the minimal set of neuronal events jointly sufficient for a specific conscious experience (Crick & Koch, 2003). Significant progress in consciousness research has come from focusing on the search for the NCC. This has led to the development of several promising theories, but these competing accounts have evolved without much cross talk between them and empirical research has focused on testing aspects of each theory separately, rather than on directly contrasting them to evaluate their explanatory and predictive power. To accelerate progress, the current study is based on adversarial collaboration involving the scientists who co-developed two leading theories of consciousness: Global Neural Workspace (GNW) and Integrated Information Theory (IIT). In addition, this project has been preregistered and includes built-in replications by at least two independent laboratories with separate subject populations, open data/protocols for reproducibility, and large sample sizes for statistical robustness. Taken together, these open science and collaborative practices are intended to yield reliable results that can arbitrate between the theories by testing opposing predictions. In a unified experimental approach, this study combines complementary neuroimaging methods, so that each experimental design (detailed below) is used with three methodologies: functional magnetic resonance imaging (fMRI), electrocorticography (ECoG) and simultaneous magnetoencephalography/electroencephalography (M-EEG). This maximizes sensitivity, spatiotemporal resolution, and whole brain coverage to test core and auxiliary predictions of the theories. As a model system, we focus on conscious vision in adult human subjects, which historically provides the clearest background in terms of known anatomical and functional properties. Below we attach a preregistration file which details the theoretical background, hypotheses, experimental approach and planned analysis. This is the fourth version of the preregistration, including all specific analysis for Experiment 1. To see the previous versions of this preregistration, as well as additional materials, see here: https://osf.io/mbcfy/