**Acknowledgements**

*Visual Impairment and Blindness - What We Know and What We Have to Know*

cue in the spatial evaluation, perceiving an illusory spatial position of the sound

*Graphical model of our theory. In sighted individuals, spatial estimation is independent of the temporal cue of the stimulus for both coherent (A) and conflicting (B) information. Blind individuals infer spatial information using temporal coordinates of the stimulus assuming constant velocity. When spatial-temporal coherent stimuli are present, the spatial estimation can be successfully extracted by the temporal cue (C). On the other hand, when conflicting spatial-temporal information (D) is provided, the temporal cue is wrongly used to drive the* 

A lack of vision hampers strategies and neural circuits underlying complex spatial metrics, driving to multisensory interactions that bring to code space based

These findings support the cross-sensory calibration theory [5, 61], suggesting that visual information is necessary for normal development of auditory sense of space. In children younger than 12 years of age, there is visual dominance over audition in spatial bisection, and an auditory dominance over vision in temporal bisection [5]. The cross-sensory calibration of the visual system for the spatial bisection explains why blind subjects show a specific temporal response to the spatial bisection task, while also showing different processing to solve Euclidean, metric, relationships. We can speculate that these processes could be mediated in sighted but not in blind people by pathways involving the superior colliculus [30, 55, 62]. The present study adds new evidence, showing other possible interactions during development among sensory modalities, as well as spatial and temporal

based on its temporal coordinates (**Figure 7** right).

*spatial sound position assuming constant velocity.*

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domains.

**Figure 7.**

**8. Conclusion**

The authors acknowledge the contribution of David Burr and Concetta Morrone in helping to shape the line of research that forms the basis of this chapter, including their continuous support and their participation in some of the experiments reported.
