Auditory, tactile, and audiotactile information processing following visual deprivation.

Abstract

We highlight the results of those studies that have investigated the plastic reorganization processes that occur within the human brain as a consequence of visual deprivation, as well as how these processes give rise to behaviorally observable changes in the perceptual processing of auditory and tactile information. We review the evidence showing that visual deprivation affects the establishment of the spatial coordinate systems involved in the processing of auditory and tactile inputs within the peripersonal space around an individual. In blind individuals, the absence of a conjoint activation of external coordinate systems across modalities co-occurs with a higher capacity to direct auditory and tactile attentional resources to different spatial locations and to ignore irrelevant distractors. Both processes could thus contribute to the reduced spatial multisensory binding that has been observed in those who are blind. The interplay between auditory and tactile information in visually deprived individuals is modulated by attentional factors. Blind individuals typically outperform sighted people in those tasks where the target is presented in one sensory modality (and the other modality acts as a distractor). By contrast, they are less efficient in tasks explicitly requiring the combination of information across sensory modalities. The review highlights how these behavioral effects are subserved by extensive plastic changes at the neural level, with brain areas traditionally involved in visual functioning switching and being recruited for the processing of stimuli within the intact residual senses. We also discuss the roles played by other intervening factors with regard to compensatory mechanisms, such as previous visual experience, age at onset of blindness, and learning effects.

Auditory distance perception in humans: a review of cues, development, neuronal bases, and effects of sensory loss

“…Very little is currently known regarding the effects of partial non-correctable visual loss on auditory distance perception, and perceptual processing in this population remains under-researched relative to that for those with total visual losses (Occelli, Spence, & Zampini, 2013 ). Kolarik et al( 2013b ) found no difference in auditory distance discrimination using level, DRR, or both cues between a partially sighted group and a normally sighted group, whereas enhanced performance was found for those with full visual loss.…”

Designing sensory-substitution devices: Principles, pitfalls and potential1

“…This demonstrates the operation of interpretative mechanisms in perception (section 1). It is also of great interest that congenitally blind participants were not as prone to the auditory-tactile illusion as sighted participants, suggesting that multisensory integration may differ in the congenitally blind, perhaps because they have better auditory discrimination abilities than sighted people or because vision plays a role in crossmodal calibration ( Gori et al, 2010 ; Occelli, Spence & Zampini, 2013 ). The McGurk effect is another example of a multimodal illusion where lip movements and heard speech interact ( McGurk & MacDonald, 1976 ).…”

Visual Experience Determines the Use of External Reference Frames in Joint Action Control

“…Due to their lack of vision, congenitally-blind people need to rely more on their remaining senses, such as audition, touch or proprioception. It has been shown that extensive use of remaining sensory modalities can result in superior performance of congenitally-blind people, compared to sighted people, in perceptual, spatial, and attentional tasks [43], [44]. Therefore, congenitally blind participants may have effectively used the available auditory and tactile information provided by the co-actor, i.e., they used an agent-based reference frame, in order to build up a more reliable spatial target representation than they would by using response-based coding alone.…”

“…There is evidence that congenitally-blind people compensate for the lack of visual input with their remaining senses, to some extent ( compensatory hypothesis , [43]). A more extensive use of these senses can result in superior perceptual and spatial skills, as well as more efficient attentional processes [43]–[44]. In contrast to the response buttons, a responding co-actor in the social Simon task can provide direct auditory and tactile feedback about his/her location in space, which offers a reliable spatial reference (e.g., by crossing participants' arms over one another) and, thus, may facilitate agent-based coding.…”