How Does Experience Modulate Auditory Spatial Processing in Individuals with Blindness?

Abstract

Comparing early- and late-onset blindness in individuals offers a unique model for studying the influence of visual experience on neural processing. This study investigated how prior visual experience would modulate auditory spatial processing among blind individuals. BOLD responses of early- and late-onset blind participants were captured while performing a sound localization task. The task required participants to listen to novel “Bat-ears” sounds, analyze the spatial information embedded in the sounds, and specify out of 15 locations where the sound would have been emitted. In addition to sound localization, participants were assessed on visuospatial working memory and general intellectual abilities. The results revealed common increases in BOLD responses in the middle occipital gyrus, superior frontal gyrus, precuneus, and precentral gyrus during sound localization for both groups. Between-group dissociations, however, were found in the right middle occipital gyrus and left superior frontal gyrus. The BOLD responses in the left superior frontal gyrus were significantly correlated with accuracy on sound localization and visuospatial working memory abilities among the late-onset blind participants. In contrast, the accuracy on sound localization only correlated with BOLD responses in the right middle occipital gyrus among the early-onset counterpart. The findings support the notion that early-onset blind individuals rely more on the occipital areas as a result of cross-modal plasticity for auditory spatial processing, while late-onset blind individuals rely more on the prefrontal areas which subserve visuospatial working memory.

Mental Imagery Follows Similar Cortical Reorganization as Perception: Intra-Modal and Cross-Modal Plasticity in Congenitally Blind

“…The ROI-SVM results further showed that perception modality could be decoded from cross-modal activity in the primary visual cortex and V2-V5 in both the blind and sighted groups, consistent with our hypothesis that the visual cortex would be recruited during auditory and tactile perception by the blind participants. Earlier research has shown that functional reorganization of the visual cortex after visual deprivation makes it responsive to a large variety of haptic and auditory tasks (Rosler et al 1993;Roder et al 1997;Burton et al 2003;Ricciardi et al 2007;Amedi et al 2010;Dietrich et al 2013;Lewald and Getzmann 2013;Occelli et al 2013;Watkins et al 2013;Striem-Amit and Amedi 2014;Anurova et al 2015;Bauer et al 2015;Lane et al 2015;Tao et al 2015). Interestingly, in line with those findings, our results also indicate that auditory and tactile modalities can be differentiated in early and extrastriate visual cortex, showing that they do not activate visual cortex in a similar manner.…”

“…These different results may depend on the specific task requirements (King 2014), or may reflect a trade-off between different auditory abilities (Voss et al 2015). Moreover, neural differences in auditory processing between blind and sighted participants have been found (Schepers et al 2012;Watkins et al 2013;Holig et al 2014a;Jiang et al 2014;Coullon et al 2015;Guerreiro et al 2016;Murphy et al 2016;Derey et al submitted), wheresimilar to haptic processing -the visual cortex is more strongly involved in blind participants during auditory perception (Burton et al 2003;Dietrich et al 2013;Lewald and Getzmann 2013;Occelli et al 2013;Watkins et al 2013;Striem-Amit and Amedi 2014;Anurova et al 2015;Lane et al 2015;Tao et al 2015). Enhanced performance of blind people on auditory tasks also seems to be related to differences in underlying anatomical changes, e.g.…”

The neurophysiological basis of short- and long-term ventriloquism aftereffects

“…sound localization, such as the precuneus (Lewald et al 2008;Tao et al 2015). The present data suggest that these regions mediate the ventriloquism aftereffect over multiple time scales, highlighting that structures involved in spatial working or procedural memory play a central role for this adaptive behavior (Schott et al 2019) (Mueller 2018).…”

Aging Effect on Audiovisual Integrative Processing in Spatial Discrimination Task

“…The auditory stimuli used were the sounds produced by “Bat ears” previously used in two studies on sound localization processes in individuals with blindness (Chan et al, 2012 ; Tao et al, 2015 ). The Bat ears emit ultrasound signals (into the environment), receive their echoes (from surrounding obstacles), and convert them into audible “da-da-da” sounds (via a binaural earphone).…”