Beat Detection Recruits the Visual Cortex in Early Blind Subjects.

Rodrigo Araneda,Anne G De Volder,Laurence Dricot,Sandra Silva Moura

doi:10.3390/life11040296

Rodrigo Araneda, Anne G De Volder + Show 2 more

Open Access

https://doi.org/10.3390/life11040296

Copy DOI

Abstract

Using functional magnetic resonance imaging, here we monitored the brain activity in 12 early blind subjects and 12 blindfolded control subjects, matched for age, gender and musical experience, during a beat detection task. Subjects were required to discriminate regular (“beat”) from irregular (“no beat”) rhythmic sequences composed of sounds or vibrotactile stimulations. In both sensory modalities, the brain activity differences between the two groups involved heteromodal brain regions including parietal and frontal cortical areas and occipital brain areas, that were recruited in the early blind group only. Accordingly, early blindness induced brain plasticity changes in the cerebral pathways involved in rhythm perception, with a participation of the visually deprived occipital brain areas whatever the sensory modality for input. We conclude that the visually deprived cortex switches its input modality from vision to audition and vibrotactile sense to perform this temporal processing task, supporting the concept of a metamodal, multisensory organization of this cortex.

Highlights

In adults affected by early visual deprivation, a crossmodal recruitment of the occipital cortex has been observed during auditory, tactile and olfactory processing [1,2,3,4,5,6,7] and during higher-level cognitive tasks such as verbal processing, complex haptic tasks, memory tasks or braille reading [8,9,10,11,12,13]
Most studies focused on the crossmodal changes in the visual brain areas in tasks performed by different sensory modalities, intramodal changes have been observed in the auditory [19,20,21] and the somatosensory cortices [22,23,24,25] indicating that early blindness trigger changes in brain areas dedicated to the preserved sensory modalities
A non parametric Mann–Whitney test performed on these scores revealed differences between early blind participants and their controls (audio accuracy for early blind participants: median score = 10.000 (25–75%: 9.250–10.000); audio accuracy for controls; median score = 9.000 (25–75%: 8.250–9.750, p = 0.011); tact accuracy for early blind participants: median score = 9.000 (25–75%: 8.250–10.000); tact accuracy for controls: median score = 8.000 (25–75%: 6.000–9.000, p = 0.040)

Summary

Introduction

In adults affected by early visual deprivation, a crossmodal recruitment of the occipital cortex has been observed during auditory, tactile and olfactory processing [1,2,3,4,5,6,7] and during higher-level cognitive tasks such as verbal processing, complex haptic tasks, memory tasks or braille reading [8,9,10,11,12,13]. In blind subjects functional connectivity reorganizations between the sensory and heteromodal brain areas have been observed [9,26], highlighting that neuroplastic modifications may arise in brain networks larger than the visual cortices, including regions associated with multimodal integration [27,28]. These integration areas have been described as critical for higher cognitive functions involved in the construction of an integrated, multisensory experience [29,30]. Beat perception can be achieved via most sensory modalities as shown in behavioral and neuroimaging studies, it is best accomplished in audition [31,34,35,36,37,38]

Methods

Results

Discussion

Conclusion