| 1. |
- Andin, Josefine, 1979-, et al.
(author)
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Similar digit-based working memory in deaf signers and hearing non-signers despite digit span differences
- 2013
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In: Frontiers in Psychology. - : Frontiers Media SA. - 1664-1078. ; 4:942
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Journal article (peer-reviewed)abstract
- Similar working memory (WM) for lexical items has been demonstrated for signers and non-signers while short-term memory (STM) is regularly poorer in deaf than hearing individuals. In the present study, we investigated digit-based WM and STM in Swedish and British deaf signers and hearing non-signers. To maintain good experimental control we used printed stimuli throughout and held response mode constant across groups. We showed that deaf signers have similar digit-based WM performance, despite shorter digit spans, compared to well-matched hearing non-signers. We found no difference between signers and non-signers on STM span for letters chosen to minimize phonological similarity or in the effects of recall direction. This set of findings indicates that similar WM for signers and non-signers can be generalized from lexical items to digits and suggests that poorer STM in deaf signers compared to hearing non-signers may be due to differences in phonological similarity across the language modalities of sign and speech.
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| 2. |
- Cardin, Velia, et al.
(author)
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Differential activity in Heschl's gyrus between deaf and hearing individuals is due to auditory deprivation rather than language modality
- 2016
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In: NeuroImage. - : Elsevier BV. - 1053-8119 .- 1095-9572. ; 124, s. 96-106
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Journal article (peer-reviewed)abstract
- Sensory cortices undergo crossmodal reorganisation as a consequence of sensory deprivation. Congenital deafness in humans represents a particular case with respect to other types of sensory deprivation, because cortical reorganisation is not only a consequence of auditory deprivation, but also of language-driven mechanisms. Visual crossmodal plasticity has been found in secondary auditory cortices of deaf individuals, but it is still unclear if reorganisation also takes place in primary auditory areas, and how this relates to language modality and auditory deprivation.Here, we dissociated the effects of language modality and auditory deprivation on crossmodal plasticity in Heschl's gyrus as a whole, and in cytoarchitectonic region Te1.0 (likely to contain the core auditory cortex). Using fMRI, we measured the BOLD response to viewing sign language in congenitally or early deaf individuals with and without sign language knowledge, and in hearing controls.Results show that differences between hearing and deaf individuals are due to a reduction in activation caused by visual stimulation in the hearing group, which is more significant in Te1.0 than in Heschl's gyrus as a whole. Furthermore, differences between deaf and hearing groups are due to auditory deprivation, and there is no evidence that the modality of language used by deaf individuals contributes to crossmodal plasticity in Heschl's gyrus.
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| 3. |
- Cardin, Velia, et al.
(author)
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Dissociating cognitive and sensory neural plasticity in human superior temporal cortex
- 2013
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In: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 4:2
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Journal article (peer-reviewed)abstract
- Disentangling the effects of sensory and cognitive factors on neural reorganization is fundamental for establishing the relationship between plasticity and functional specialization. Auditory deprivation in humans provides a unique insight into this problem, because the origin of the anatomical and functional changes observed in deaf individuals is not only sensory, but also cognitive, owing to the implementation of visual communication strategies such as sign language and speechreading. Here, we describe a functional magnetic resonance imaging study of individuals with different auditory deprivation and sign language experience. We find that sensory and cognitive experience cause plasticity in anatomically and functionally distinguishable substrates. This suggests that after plastic reorganization, cortical regions adapt to process a different type of input signal, but preserve the nature of the computation they perform, both at a sensory and cognitive level.
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| 4. |
- Cardin, Velia, et al.
(author)
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Monitoring Different Phonological Parameters of Sign Language Engages the Same Cortical Language Network but Distinctive Perceptual Ones
- 2016
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In: Journal of cognitive neuroscience. - : MIT Press - Journals. - 0898-929X .- 1530-8898. ; 28:1, s. 20-40
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Journal article (peer-reviewed)abstract
- The study of signed languages allows the dissociation of sensorimotor and cognitive neural components of the language signal. Here we investigated the neurocognitive processes underlying the monitoring of two phonological parameters of sign languages: handshape and location. Our goal was to determine if brain regions processing sensorimotor characteristics of different phonological parameters of sign languages were also involved in phonological processing, with their activity being modulated by the linguistic content of manual actions. We conducted an fMRI experiment using manual actions varying in phonological structure and semantics: (1) signs of a familiar sign language (British Sign Language), (2) signs of an unfamiliar sign language (Swedish Sign Language), and (3) invented nonsigns that violate the phonological rules of British Sign Language and Swedish Sign Language or consist of nonoccurring combinations of phonological parameters. Three groups of participants were tested: deaf native signers, deaf nonsigners, and hearing nonsigners. Results show that the linguistic processing of different phonological parameters of sign language is independent of the sensorimotor characteristics of the language signal. Handshape and location were processed by different perceptual and task-related brain networks but recruited the same language areas. The semantic content of the stimuli did not influence this process, but phonological structure did, with nonsigns being associated with longer RTs and stronger activations in an action observation network in all participants and in the supramarginal gyrus exclusively in deaf signers. These results suggest higher processing demands for stimuli that contravene the phonological rules of a signed language, independently of previous knowledge of signed languages. We suggest that the phonological characteristics of a language may arise as a consequence of more efficient neural processing for its perception and production.
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