Attention is often conceived as a gateway to consciousness . Although endogenous spatial attention may be independent of conscious perception , exogenous spatial orienting seems instead to be an important modulator of CP . Here, we investigate the role of auditory alerting in CP in normal observers. We used a behavioral task in which phasic alerting tones were presented either at unpredictable or at predictable time intervals prior to the occurrence of a near-threshold visual target. We find, for the first (...) time in neurologically intact observers, that phasic alertness increases CP, both objectively and subjectively. This result is consistent with evidence showing that phasic alerting can ameliorate the spatial bias exhibited by visual neglect patients . The alerting network may increase the activity of fronto-parietal networks involved in top-down amplification required to bring a stimulus into consciousness. (shrink)

A period of exposure to trains of simultaneous but spatially offset auditory and visual stimuli can induce a temporary shift in the perception of sound location. This phenomenon, known as the 'ventriloquist aftereffect', reflects a realignment of auditory and visual spatial representations such that they approach perceptual alignment despite their physical spatial discordance. Such dynamic changes to sensory representations are likely to underlie the brain's ability to accommodate inter-sensory discordance produced by sensory errors (particularly in sound localization) and variability in (...) sensory transduction. It is currently unknown, however, whether these plastic changes induced by adaptation to spatially disparate inputs occurs automatically or whether they are dependent on selectively attending to the visual or auditory stimuli. Here, we demonstrate that robust auditory spatial aftereffects can be induced even in the presence of a competing visual stimulus. Importantly, we found that when attention is directed to the competing stimuli, the pattern of aftereffects is altered. These results indicate that attention can modulate the ventriloquist aftereffect. © 2010 Elsevier B.V. (shrink)