Is this normalization framework a general property of visual competition? Although attention can deftly regulate neural representations, the process of conflict resolution is not always so seamless. In some instances, the visual system struggles to reconcile competing sensory information, a compelling example being when dissimilar images are presented to the two eyes. In this case, visual awareness alternates between the two images, creating the phenomenon known as binocular rivalry (Blake and Logothetis,

2002; Leopold and Logothetis, 1999; Tong et al., 2006; Wheatstone, 1838). Binocular rivalry offers a unique opportunity to probe competitive processes within the brain, by allowing check details us to see with our own eyes a process that ordinarily transpires outside of our awareness, namely dynamic competition between neural representations (Blake and Logothetis, 2002; Leopold and Logothetis, 1999). Here, we explore whether a common neural computation may mediate competitive processes embodied in rivalry and in attention. The notion that attention and rivalry are intertwined

has been debated for over a century (von Helmholtz, 1909; James, 1890; Lack, 1978; Zhang et al., 2011; Watanabe et al., 2011), and some have gone so far as to directly attribute the alternations in visual awareness to switches in attention (von Helmholtz, 1909; Lack, 1978). Moreover, a growing body PLK inhibitor of research suggests that modulation of visual awareness through rivalry

in early visual cortices depends on attentional state (Lee et al., 2007; Zhang et al., 2011; Watanabe et al., 2011). However, the mechanisms subserving these interactions between attention and rivalry remain unknown. Here, we develop and test the idea that attention and rivalry reconcile competing visual information via a common framework, one in which modulation of awareness through rivalry interacts with attention. We propose Non-specific serine/threonine protein kinase a computation model for visual competition, whereby modulation of competing neural signals relies on interactions between normalization and attention: gain modulation depends on the size of the competitor stimulus and the attentional state. Finally, we empirically test a core prediction of this computational model, revealing that the degree of suppression between competing neural representations is regulated by attentional state. The normalization model of attention makes a very clear prediction: changing the size of the “attentional field” relative to the stimulus will differentially modulate the signal’s contrast response, causing either contrast gain or response gain modulation depending on the configuration (Reynolds and Heeger, 2009; Herrmann et al., 2010). Under binocular rivalry, the stimulus presented in one eye typically abolishes the visibility of a rival stimulus in the other eye.