Chapters authored
Audio Cortical Processing in Blind Individuals
This chapter focuses on the cortical processing of auditory spatial information in blindness. Research has demonstrated enhanced auditory processing in blind individuals, suggesting they compensate for lacking vision with greater sensitivity in other senses. A few years ago, we demonstrated severely impaired auditory precision in congenitally blind individuals when performing an auditory spatial metric task: participants’ thresholds for spatially bisecting three consecutive, spatially distributed sound sources were seriously compromised. Here we describe psychophysical and neural correlates of this deficit, and we show that the deficit disappears if blind individuals are presented with coherent spatio-temporal cues (short space associated with short time and vice versa). Instead, when the audio information presents incoherent spatio-temporal cues (short space associated with long time and vice versa), sighted individuals are unaffected by the perturbation while blind individuals are strongly attracted to the temporal cue. These results suggest that blind participants use temporal cues to make audio spatial estimations and that the visual cortex seems to have a functional role in these perceptual tasks. In the present chapter, we illustrate our hypothesis, suggesting that the lack of vision may drive construction of multisensory cortical network coding space based on temporal instead of spatial coordinates.
Part of the book: Visual Impairment and Blindness
The Role of Vision on Spatial Competence
Several pieces of evidence indicate that visual experience during development is fundamental to acquire long-term spatial capabilities. For instance, reaching abilities tend to emerge at 5 months of age in sighted infants, while only later at 10 months of age in blind infants. Moreover, other spatial skills such as auditory localization and haptic orientation discrimination tend to be delayed or impaired in visually impaired children, with a huge impact on the development of sighted-like perceptual and cognitive asset. Here, we report an overview of studies showing that the lack of vision can interfere with the development of coherent multisensory spatial representations and highlight the contribution of current research in designing new tools to support the acquisition of spatial capabilities during childhood.
Part of the book: Visual Impairment and Blindness