Cultural diversity and biological unity in dyslexia

Paulesu, Eraldo; Démonet, Jean François; Fazio, Ferruccio; Crory, Eamon Mc; Chanoine, Valérie; Brunswick, Nicola; Cappa, Stefano F.; Cossu, Giuseppe; Habib, Michel; Frith, C; Frith, Uta

doi:10.1016/s1053-8119(01)91927-5

Cited by 186 publications

(287 citation statements)

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“…Over the course of years of extensive experience in extracting invariant information from visual word stimuli, perceptual processes are progressively reorganized, but only in those who become skilled readers. Research with dyslexic adults indicates that, among other areas, the VWFA fails to increase its activity in response to word forms [44,45] (Box 3). A basic functional anatomical model of the typical development of this specialization might provide a framework for the investigation and treatment of atypical development, as in the case of developmental dyslexia.…”

Section: V4 V4mentioning

confidence: 99%

“…Adults with a history of developmental dyslexia demonstrate a reduced tendency to activate VWFA (see Fig. I), among other regions, in response to visual words and pseudowords as measured by fMRI [44,45] and MEG responses within the first 200 ms [14]. Such differences have not yet been associated with neuropathology in this region, but may instead reflect the absence of a specialization that accrues over the course of years of successful reading experience [55].…”

Section: Box 3 Vwfa In Developmental Dyslexiamentioning

confidence: 99%

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The visual word form area: expertise for reading in the fusiform gyrus

McCandliss

Cohen

Dehaene

2003

Trends in Cognitive Sciences

1,301

934

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Brain imaging studies reliably localize a region of visual cortex that is especially responsive to visual words. This brain specialization is essential to rapid reading ability because it enhances perception of words by becoming specifically tuned to recurring properties of a writing system. The origin of this specialization poses a challenge for evolutionary accounts involving innate mechanisms for functional brain organization. We propose an alternative account, based on studies of other forms of visual expertise (i.e. bird and car experts) that lead to functional reorganization. We argue that the interplay between the unique demands of word reading and the structural constraints of the visual system lead to the emergence of the Visual Word Form Area.Years after children first learn to decode letters into words, a form of perceptual expertise emerges in which groups of letters are rapidly and effortlessly conjoined into integrated visual percepts -a process that is crucial to fluent reading ability. This article reviews the current evidence in support of a link between visual word form perception and a functional specialization in a brain region that we propose to call the 'Visual Word Form Area' (VWFA) -a portion of the left fusiform gyrus that is particularly responsive to visual words. Systematic exploration of the response properties of this region reveals sensitivity to specific and abstract qualities of visual word forms that are not easily attributable to more basic stimulus properties, and are also separable from higher-order linguistic properties.Considering the origin of VWFA poses a paradox for evolutionary accounts of functional specialization of extrastriate visual areas, given that the cultural invention of writing upon which this specialization is predicated did not exist until , 5400 years ago, which is insufficient time for selective pressures to engineer a specialized 'module' for visual word recognition. Instead, we suggest a developmental process through which reading experience drives progressive specialization of a pre-existing inferotemporal pathway for visual object recognition. Under this view, the rise of perceptual expertise in word recognition provides a remarkable example of how specialization processes within the visual system can accommodate a novel cultural invention. Perceptual expertise underlying visual word recognitionLiterate adults possess a special form of visual expertise that allows their visual system to process words efficiently. Within less than 250 ms of viewing a written word, the visual system extracts the information needed to identify its linguistic significance, despite wide variations in print, script, font, size and retinal position. Several lines of cognitive evidence indicate that the perceptual mechanisms that support word recognition rest on a critical process that groups the letters of a word together into an integrated perceptual unit (i.e. a 'visual word form'). This process is highly sensitive to the abstract structural properties of the writing syste...

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Section: V4 V4mentioning

confidence: 99%

Section: Box 3 Vwfa In Developmental Dyslexiamentioning

confidence: 99%

The visual word form area: expertise for reading in the fusiform gyrus

McCandliss

Cohen

Dehaene

2003

Trends in Cognitive Sciences

1,301

934

View full text Add to dashboard Cite

show abstract

“…However, while phonological impairments are indeed found in a clear majority of the studies (Melby-Lervag, Lyster, & Hulme, 2012;Ramus & Ahissar, 2012;Ziegler & Goswami, 2005), the presumption of an etiological and causal role for these phonological problems in relation to reading is not without its critics (Blomert & Willems, 2010;Castles & Coltheart, 2004). Most importantly, there is evidence for a double dissociation between dyslexia and phonological deficits: some individuals with Serial-order learning in dyslexia severe reading disability do not show a phonological impairment, while some children with an apparent phonological deficit nevertheless do achieve fluency in (word) reading (Paulesu et al, 2001;Wimmer, Mayringer, & Landerl, 2000). Moreover, it is unclear how some of the nonlinguistic impairments often associated with dyslexia (e.g., implicit learning or motor deficits) may be accounted for by phonological deficits.…”

Section: Dyslexiamentioning

confidence: 99%

Linking memory and language: Evidence for a serial-order learning impairment in dyslexia

Bogaerts

Szmalec

Hachmann

et al. 2015

Research in Developmental Disabilities

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The present study investigated long-term serial-order learning impairments, operationalized as reduced Hebb repetition learning (HRL), in people with dyslexia. In a first multi-session experiment, we investigated both the persistence of a serial-order learning impairment as well as the long-term retention of serial-order representations, both in a group of Dutch-speaking adults with developmental dyslexia and in a matched control group. In a second experiment, we relied on the assumption that HRL mimics naturalistic word-form acquisition and we investigated the lexicalization of novel wordforms acquired through HRL. First, our results demonstrate that adults with dyslexia are fundamentally impaired in the long-term acquisition of serial-order information. Second, dyslexic and control participants show comparable retention of the long-term serial-order representations in memory over a period of one month. Third, the data suggest weaker lexicalization of newly acquired word-forms in the dyslexic group. We discuss the integration of these findings into current theoretical views of dyslexia.

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“…Boatman et al (1997) have reported in five patients that the stimulation of one temporal electrode in this region elicited a deficit in syllable discrimination. The more posterior part of the temporal region is also activated when phonological representations are accessed through devices other than auditory input, such as lip reading (Calvert and Campbell, 2003;Calvert et al, 1997), word generation (Buchsbaum et al, 2001;Wise et al, 2001), sign language processing (Petitto et al, 2000), and reading (Paulesu et al, 2000(Paulesu et al, , 2001. It is possible that top-down attention amplifies those speech representation, thus bringing knowledge of the characteristics of a human voice to supplement the poverty of the sinewave input and integrate its acoustical features into phonemic representations.…”

Section: Fmrimentioning

confidence: 99%

Neural correlates of switching from auditory to speech perception

et al. 2005

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Many people exposed to sinewave analogues of speech first report hearing them as electronic glissando and, later, when they switch into a dspeech modeT, hearing them as syllables. This perceptual switch modifies their discrimination abilities, enhancing perception of differences that cross phonemic boundaries while diminishing perception of differences within phonemic categories. Using high-density evoked potentials and fMRI in a discrimination paradigm, we studied the changes in brain activity that are related to this change in perception. With ERPs, we observed that phonemic coding is faster than acoustic coding: The electrophysiological mismatch response (MMR) occurred earlier for a phonemic change than for an equivalent acoustic change. The MMR topography was also more asymmetric for a phonemic change than for an acoustic change. In fMRI, activations were also significantly asymmetric, favoring the left hemisphere in both perception modes. Furthermore, switching to the speech mode significantly enhanced activation in the posterior parts of the left superior gyrus and sulcus relative to the non-speech mode. When responses to a change of stimulus were studied, a cluster of voxels in the supramarginal gyrus was activated significantly more by a phonemic change than by an acoustic change. These results demonstrate that phoneme perception in adults relies on a specific and highly efficient left-hemispheric network, which can be activated in top-down fashion when processing ambiguous speech/non-speech stimuli.

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Cultural diversity and biological unity in dyslexia

Cited by 186 publications

References 0 publications

The visual word form area: expertise for reading in the fusiform gyrus

The visual word form area: expertise for reading in the fusiform gyrus

Linking memory and language: Evidence for a serial-order learning impairment in dyslexia

Neural correlates of switching from auditory to speech perception

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