The Extent of Task Specificity for Visual and Tactile Sequences in the Auditory Cortex of the Deaf and Hard of Hearing

Abstract

It has been proposed that the auditory cortex in the deaf humans might undergo task-specific reorganization. However, evidence remains scarce as previous experiments used only two very specific tasks (temporal processing and face perception) in visual modality. Here, congenitally deaf/hard of hearing and hearing women and men were enrolled in an fMRI experiment as we sought to fill this evidence gap in two ways. First, we compared activation evoked by a temporal processing task performed in two different modalities, visual and tactile. Second, we contrasted this task with a perceptually similar task that focuses on the spatial dimension. Additional control conditions consisted of passive stimulus observation. In line with the task specificity hypothesis, the auditory cortex in the deaf was activated by temporal processing in both visual and tactile modalities. This effect was selective for temporal processing relative to spatial discrimination. However, spatial processing also led to significant auditory cortex recruitment which, unlike temporal processing, occurred even during passive stimulus observation. We conclude that auditory cortex recruitment in the deaf and hard of hearing might involve interplay between task-selective and pluripotential mechanisms of cross-modal reorganization. Our results open several avenues for the investigation of the full complexity of the cross-modal plasticity phenomenon.

Somatosensory processing in deaf and deafblind individuals: How does the brain adapt as a function of sensory and linguistic experience? A critical review

“…Moreover, analyses revealed a correlation between temporal discrimination task performance and the effect of disruption by STG-TMS at 180 ms: The better the behavioral performance, the larger the disruption induced by the STG-TMS at that time point. In a recent fMRI study, Zimmermann et al (2021) also found different results for temporal vs. spatial somatosensory processing in a group of deaf and hard-of-hearing participants ( n = 21). All participants were signers of Polish Sign Language (PJM), and their age of acquisition ranged from birth to primary school entry.…”

“…An interesting case of somatosensory processing in deaf and deafblind individuals are temporal tasks. Several studies have pointed to neural differences regarding spatial vs. temporal processing and the assumption that compared to hearing individuals, deaf individuals might show disadvantages in temporal processing (e.g., Heming and Brown, 2005;Bolognini et al, 2010Bolognini et al, , 2012Papagno et al, 2016;Zimmermann et al, 2021). Bolognini et al (2012) found a correlation between auditory cortex involvement latency and behavioral performance in a temporal task.…”

“…This review will focus on studies on crossmodal plasticity , which concerns changes in areas that are typically associated with a modality that is not received and processed. Examples are higher activity in auditory areas in deaf compared to hearing individuals during visual stimulation ( Finney et al, 2001 ; Fine et al, 2005 ; Benetti et al, 2021 ) and tactile stimulation ( Karns et al, 2012 ; Zimmermann et al, 2021 ), or activity in visual areas of blind individuals who are listening to speech ( Bedny et al, 2011 ). Benetti et al (2021) presented patterns of moving dots and observed significantly stronger activation in typical auditory areas in early deaf participants compared to hearing signers and non-signers.…”

Auditory areas are recruited for naturalistic visual meaning in early deaf people

“…In fact, activations of the primary auditory cortex in the deaf induced by visual or tactile tasks are generally modest or absent. Various tasks, including language (MacSweeney et al, 2004), visual semantic task (Twomey, et al 2017) working memory (Cardin et al 2018) face recognition (Benetti, et al 2017), visual motion perception (Benetti, et al 2021) and tactile and visual sensory discrimination (Bola, et al 2017, Zimmermann, et al 2021) fail to evoke activation in A1. Analogously, the primary auditory cortex in the deaf cat also does not show effects of cross-modal reorganization (Kral et al, 2003(Kral et al, , 2017.…”

“…These mechanisms are known to be right lateralized (Corbetta & Shulman, 2002). Task-based studies on deafness show significant right posterior STG activations for several attention-related functions and perceptual tasks such as spatial and temporal sequence discrimination (Bola et al, 2017;Zimmermann et al, 2021) visual motion detection (Benetti et al, 2021), visuo-spatial working memory (Ding, et. al…”