Attention has often been conceived as the gateway to consciousness. However, recent research points to the independence of top-down or endogenous attention and conscious perception, while the role of bottom-up or exogenous attention in conscious perception remains largely unexplored. Here, we present behavioural and electrophysiological evidence exploring the role of exogenous attention in conscious perception. Using peripheral non-informative cues, exogenous attention was oriented either to the same location of a near-threshold target (valid cues), or to the opposite location (invalid cues). Confirming previous research, consciously perceived targets elicited a larger P300 than unseen targets. Importantly, analysis of cue-locked potentials revealed the novel finding that there was a systematic relationship between the amplitude of a P100 component elicited by the cues and the conscious perception of the targets. Valid cues led to the conscious perception of the subsequent targets when they captured attention to their location, as indexed by the P100 component distributed over occipito-parietal areas. On the other hand, invalid cues led to the conscious perception of the subsequent targets only when they failed to capture attention at their location (opposite to the target location). These results suggest that exogenous orienting plays a crucial role in conscious perception.
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