Decoding auditory space in hMT+/V5 and the planum temporale of the sighted and the blind individuals

The middle occipito-temporal cortex (hMT+/V5) is a region that responds preferentially to visual motion in sighted people (Tootell et al., 1995; Watson et al., 1993; Zeki et al., 1991). In case of early visual deprivation, hMT+/V5 enhances its response tuning to moving sounds (Dormal et al., 2016; Jiang et al., 2014). However, whether hMT+/V5 contains information about sound directions and whether the functional enhancement observed in the blind is motion spec

Direct Structural Connection between Auditory-temporal and Visual-occipital motion selective regions

Perceiving and integrating motion signals across sensory systems is a crucial perceptual skill for optimal interaction with a multisensory environment. In primates, including humans, the middle-temporal region (hereafter, hMT+/V5)1,2 specializes in processing visual motion signals, while the Planum Temporale (hereafter, PT) specializes for auditory motion processing3. It has been hypothesized that these regions can communicate directly to achieve fast and optimal multisensory integration of motion signals4. However, the existence of direct anatomical connections between these regions remains unexplored. We therefore evaluated the presence of anatomical connections between the hMT+/V5 and the planum temporale (PT) in fifteen healthy individuals. Each participant was first involved in an auditory and visual motion localizer in order to define PT and hMT+/V5 functionally. Then, using diffusion imaging data, we reconstructed white matter tracts between individually and functionally defined auditory and visual motion selective regions. Probabilistic tractography was conducted between each pair of regions (PT to hMT+/V5 and reversely), randomly sampling 5000 tracts per seed-voxel and keeping the samples that reached the target region. Seed and target regions were masked with individual white matter masks to avoid ill‐defined fiber orientations present in gray matter regions. A connection was considered as reliable at the individual level when it had a minimum of 10 streamlines. We found reliable connections between hMT+/V5 and PT in both hemispheres in 15 out of 15 individuals, suggesting the existence of a direct pathway between these visual and auditory selective regions. Our findings have important implications for the understanding of the multisensory nature of motion processing, as this connection might represent the structural scaffolding underlying the auditory and tactile responses observed in hMT+/V54-6

The deaf graph: Structural brain networking in auditory deprivation

Introduction: Deafness is usually accompanied by functional brain alterations that may be thought as an alteration to connectome scaffolding [1,2,3]. The general goal of this study was to investigate brain structural network organization in early and profoundly deaf subjects (ED). The specif

How input modality and visual experience affect the neural encoding of categorical knowledge

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