A recent study has shown that congenitally blind adults, who have never had visual experience, are impaired on an auditory spatial bisection task (Gori, Sandini, Martinoli, & Burr, 2014). In this study we investigated how thresholds for auditory spatial bisection and auditory discrimination develop with age in sighted and congenitally blind children (9 to 14 years old). Children performed 2 spatial tasks (minimum audible angle and space bisection) and 1 temporal task (temporal bisection). There was no impairment in the temporal task for blind children but, like adults, they showed severely compromised thresholds for spatial bisection. Interestingly, the blind children also showed lower precision in judging minimum audible angle. These results confirm the adult study and go on to suggest that even simpler auditory spatial tasks are compromised in children, and that this capacity recovers over time. Keywords visual deprivation; auditory perception; spatial perceptionVisual deprivation impacts strongly on the functional organization of the brain, especially if it occurs early in life, when cortical plasticity is maximal. The premature loss of vision causes functional reorganization of the visual cortex, which can become colonized by other sensory modalities and be activated by nonvisual stimuli (Collignon et al., 2013;Collignon et al., 2011;Rauschecker, 1995;Voss & Zatorre, 2012). The neural colonization is accompanied by improvement of many auditory and tactile abilities in congenitally blind adults. Tactile spatial acuity has been reported to be superior in the blind than in the sighted (Van Boven, Hamilton, Kauffman, Keenan, & Pascual-Leone, 2000), with the enhancement of acuity seeming to result from tactile experience (Wong, Gnanakumaran, & Goldreich, 2011). Similarly, blind adults can map auditory events with equal or better accuracy than Correspondence concerning this article should be addressed to Tiziana Vercillo, Department of Psychology, University of Nevada, 1664 North, Virginia Street, MS 296, Reno, NV 89557. tizianavercillo@hotmail.it. (Doucet et al., 2005;Lessard, Paré, Lepore, & Lassonde, 1998; Roder et al., 1999;Voss et al., 2004). These enhanced sensory abilities have been ascribed to changes within the auditory and tactile pathways (Cohen et al., 1997;Elbert et al., 2002) and also to the colonization of the visual cortex from the remaining sensory modalities (Collignon et al., 2013;Collignon et al., 2011;Collignon, Voss, Lassonde, & Lepore, 2009;Gougoux, Zatorre, Lassonde, Voss, & Lepore, 2005), supporting the hypothesis of sensory substitution (Rauschecker, 1995). Europe PMC Funders GroupHowever, there have also been reports of negative effects of prolonged visual deprivation in perceptual tasks. A recent study investigated local versus global processing in naming and haptic drawing tasks in a group of blind and sighted children and reported that analytical strategies predominate over holistic strategies in haptic perception in blind children of around 10 years of age (Puspitawati, Jeb...

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The role attention plays in our experience of a coherent, multisensory world is still controversial. On the one hand, a subset of inputs may be selected for detailed processing and multisensory integration in a top-down manner, i.e., guidance of multisensory integration by attention. On the other hand, stimuli may be integrated in a bottom-up fashion according to low-level properties such as spatial coincidence, thereby capturing attention. Moreover, attention itself is multifaceted and can be described via both top-down and bottom-up mechanisms. Thus, the interaction between attention and multisensory integration is complex and situation-dependent. The authors of this opinion paper are researchers who have contributed to this discussion from behavioural, computational and neurophysiological perspectives. We posed a series of questions, the goal of which was to illustrate the interplay between bottom-up and top-down processes in various multisensory scenarios in order to clarify the standpoint taken by each author and with the hope of reaching a consensus. Although divergence of viewpoint emerges in the current responses, there is also considerable overlap: In general, it can be concluded that the amount of influence that attention exerts on MSI depends on the current task as * Equal contribution (ordered alphabetically). ** Equal contribution. *** To whom correspondence should be addressed. E-mail: hartcher@isir.upmc.fr; Ruth.Adam@med.uni-muenchen.de Macaluso et al. / Multisensory Research (2016) well as prior knowledge and expectations of the observer. Moreover stimulus properties such as the reliability and salience also determine how open the processing is to influences of attention.

The ability to constantly anticipate events in the world is critical to human survival. It has been suggested that predictive processing originates from the motor system and that incoming sensory inputs can be altered to facilitate sensorimotor integration. In the current study, we investigated the role of the readiness potentials, i.e. the premotor brain activity registered within the fronto-parietal areas, in sensorimotor integration. We recorded EEG data during three conditions: a motor condition in which a simple action was required, a visual condition in which a visual stimulus was presented on the screen, and a visuomotor condition wherein the visual stimulus appeared in response to a button press. We measured evoked potentials before the motor action and/or after the appearance of the visual stimulus. Anticipating a visual feedback in response to a voluntary action modulated the amplitude of the readiness potentials. We also found an enhancement in the amplitude of the visual N1 and a reduction in the amplitude of the visual P2 when the visual stimulus was induced by the action rather than externally generated. Our results suggest that premotor brain activity might reflect predictive processes in sensory-motor binding and that the readiness potentials may possibly represent a neural marker of these predictive mechanisms.

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