Spatial attention and conscious perception: the role of endogenous and exogenous orienting.

Attention has often been considered to be a gateway to consciousness (Posner, Proceedings of the National Academy of Sciences of the United States of America, 91(16), 7398-7403, 1994). However, its relationship with conscious perception (CP) remains highly controversial. While theoretical models and experimental data support the role of attention in CP (Chica, Lasaponara, Lupiáñez, Doricchi, & Bartolomeo, NeuroImage, 51, 1205-1212, 2010; Dehaene, Changeux, Naccache, Sackur, & Sergent, Trends in Cognitive Sciences, 10, 204-211, 2006; Mack & Rock, Inattentional blindness, 1998), recent studies have claimed that at least some forms of attention--endogenous or top-down spatial attention--are neither sufficient nor necessary for CP (Koch & Tsuchiya, Trends in Cognitive Sciences, 11, 16-22, 2007). In the present experiments, we demonstrate the importance of exogenously triggered attention for the modulation of CP. Weak or null effects were instead observed when attention was triggered endogenously. Our data are discussed in the framework of recent neuropsychological models (Dehaene et al., Trends in Cognitive Sciences, 10, 204-211, 2006), postulating that activity within reverberating frontoparietal networks, as colocalized with spatial-orienting systems, is the brain correlate of consciously processed information.