A number-form area in the blind

Abboud, Sami; Maidenbaum, Shachar; Dehaene, Stanislas; Amedi, Amir

doi:10.1038/ncomms7026

Cited by 111 publications

(130 citation statements)

References 68 publications

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“…Last, the strong coupling from aIPS phase to pITG amplitude is interesting in light of a recent finding that the NFA region exhibits selectivity for numerical stimuli even in a congenitally blind person to whom numerical stimuli were presented auditorily (38). Our results support the biased connectivity hypothesis in regards to the development of the NFA (8): that the selectivity within the NFA may be driven by its intrinsic connectivity with the aIPS.…”

Section: Task-based and Intrinsic Coupling Of Activity Across Neuronalsupporting

confidence: 78%

“…Recently, our group used intracranial electrocorticography (ECoG) to confirm the existence of a site within the posterior inferior temporal gyrus (pITG) that selectively responds to visual numerals relative to letters, false fonts, number words, and words (37). This pITG site is located in an area subject to strong susceptibility artifact with fMRI (38, 39); however, numeral selectivity within the pITG has since been demonstrated with fMRI using advanced techniques to increase the signal-to-noise ratio in this region (38,39). Still, given the relatively low temporal resolution of the current imaging methods, it is difficult to study the Significance Humans have the unique ability to perform exact mental arithmetic, which derives from the association of symbols (e.g., "3") with discrete quantities.…”

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confidence: 99%

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Mapping human temporal and parietal neuronal population activity and functional coupling during mathematical cognition

Daitch

Foster

Schrouff

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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Brain areas within the lateral parietal cortex (LPC) and ventral temporal cortex (VTC) have been shown to code for abstract quantity representations and for symbolic numerical representations, respectively. To explore the fast dynamics of activity within each region and the interaction between them, we used electrocorticography recordings from 16 neurosurgical subjects implanted with grids of electrodes over these two regions and tracked the activity within and between the regions as subjects performed three different numerical tasks. Although our results reconfirm the presence of math-selective hubs within the VTC and LPC, we report here a remarkable heterogeneity of neural responses within each region at both millimeter and millisecond scales. Moreover, we show that the heterogeneity of response profiles within each hub mirrors the distinct patterns of functional coupling between them. Our results support the existence of multiple bidirectional functional loops operating between discrete populations of neurons within the VTC and LPC during the visual processing of numerals and the performance of arithmetic functions. These findings reveal information about the dynamics of numerical processing in the brain and also provide insight into the fine-grained functional architecture and connectivity within the human brain.A lthough the ability to approximate or compare rough quantities is present even in human infants (1) and in other species such as nonhuman primates (2-4) and birds (5), the association of exact quantities with symbols (e.g., the numeral "10") or verbal representations (e.g., the word "ten") is unique to humans exposed to such culturally learned entities (6-8). Moreover, dissociable number-and quantity-related behavioral deficits (i.e., deficits relating to symbolic or verbal numerical representations versus abstract quantity representations) are associated with different lesion locations within the brain (9-14). These observations in part motivated the Triple Code model positing that the human brain contains three different numerical representations: symbolic, verbal, and abstract quantity, each coded in a different brain region (15,16). The model also predicts that, depending on task demands (e.g., simple visual recognition of a numeral versus determining the larger of two numerals versus verbal naming of a numeral), all or a subset of these brain regions interact with each other (15, 16).Neuroimaging, electrophysiology, and lesion studies in both humans and nonhuman primates have long implicated the parietal lobe, particularly the anterior segment of the intraparietal sulcus (aIPS), in abstract quantity representations irrespective of the modality of presentation (e.g., "4" vs. "four" vs. "::"), with specific neurons or neuronal populations exhibiting tuning around a preferred numerosity (4, 17-25). Moreover, brain activity within this region and its functional and anatomical connectivity with other brain regions are correlated with mathematical performance in individual subjects (26)(27)(28)(29),...

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Section: Task-based and Intrinsic Coupling Of Activity Across Neuronalsupporting

confidence: 78%

mentioning

confidence: 99%

Mapping human temporal and parietal neuronal population activity and functional coupling during mathematical cognition

Daitch

Foster

Schrouff

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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“…Hence, during reading acquisition, mapping between graphemes and phonemes, or orthographic-phonological binding (7), could generate the ipsilateral left hemispheric engagement of posterior brain regions to letter strings. This view is supported by spatial constraints in establishing intrahemispheric vs. interhemispheric connections (8,16) and by privileged and/or preexisting connectivity with language areas as suggested by functional connectivity analyses in fMRI (41) and tractography (37,42).…”

Section: Early Left Lateralization For Print: Stimulus Properties or mentioning

confidence: 81%

“…First, because minimal knowledge of graphemephoneme association is sufficient to induce neural changes, it implies early establishment of functional connections between posterior visual and anterior phonological regions during development, which may be relying on preexisting structural connectivity (41,42). Second, because familiar, but not unfamiliar, symbols trigger a (right-lateralized) discrimination response, it shows that limited knowledge of certain classes of visual stimuli suffice to develop circuits that are specialized for processing these stimuli.…”

Section: Early Left Lateralization For Print: Stimulus Properties or mentioning

confidence: 99%

Left cortical specialization for visual letter strings predicts rudimentary knowledge of letter-sound association in preschoolers

Lochy¹,

Reybroeck²,

Rossion³

2016

Proc. Natl. Acad. Sci. U.S.A.

147

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Reading, one of the most important cultural inventions of human society, critically depends on posterior brain areas of the left hemisphere in proficient adult readers. In children, this left hemispheric cortical specialization for letter strings is typically detected only after approximately 1 y of formal schooling and reading acquisition. Here, we recorded scalp electrophysiological (EEG) brain responses in 5-y-old (n = 40) prereaders presented with letter strings appearing every five items in rapid streams of pseudofonts (6 items per second). Within 2 min of recording only, letter strings evoked a robust specific response over the left occipito-temporal cortex at the predefined frequency of 1.2 Hz (i.e., 6 Hz/5). Interindividual differences in the amplitude of this electrophysiological response are significantly related to letter knowledge, a preschool predictor of later reading ability. These results point to the high potential of this rapidly collected behavior-free measure to assess reading ability in developmental populations. These findings were replicated in a second experiment (n = 26 preschool children), where familiar symbols and line drawings of objects evoked right-lateralized and bilaterally specific responses, respectively, showing the specificity of the early left hemispheric dominance for letter strings. Collectively, these findings indicate that limited knowledge of print in young children, before formal education, is sufficient to develop specialized left lateralized neuronal circuits, thereby pointing to an early onset and rapid impact of left hemispheric reentrant sound mapping on posterior cortical development.A dult expert reading, a complex yet effortless and fast process (i.e., occurring at an average of 200 ms per word; ref. 1), critically depends on the left ventral occipito-temporal cortex (2). This left hemispheric specialization is thought to arise during children's reading acquisition through reentrant mapping of sound representations in the left temporal and frontal cortices to letter representations in ipsilateral posterior areas (3-5). Even though the exact onset of this leftward specialization is not known, this process appears to take considerable time during formal reading acquisition (6-8).Functional magnetic resonance imaging (fMRI) reveals the typical left lateralized adult-like brain pattern for letter strings only in proficient readers (ref. 9 for a metaanalysis) and in natural settings, significant left lateralization appears only when children have already acquired formal reading ability, approximately at 7 y of age (10). In developmental studies with direct measures of brain activity (electro/magneto-encephalography, EEG/MEG), the typical reading adult occipito-temporal response evoked by letter strings at approximately 200 ms after stimulus onset (i.e., N1 or N170; refs. 11 and 12) is absent in preschool children, even if they can already categorize or name letters. Typically, sensitivity to print has been shown after 1 y (13), or 1.5 y of schooling (14), thus, afte...

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“…In humans, there is also evidence for segregated activations for letters and numerals in the fusiform gyrus (Polk et al, 2002;Shum et al, 2013;Abboud et al, 2015), and for Chinese vs alphabetic stimuli in the early visual cortex (Szwed et al, 2014). There are also some indications of segregated activations for printed words and musical notation in the occipitotemporal cortex (Wong and Gauthier, 2010a), but this evidence is controversial (Muayqil et al, 2015) and is not supported by statistical comparisons of activation topography between words and music.…”

Section: Accepted Manuscriptmentioning

confidence: 83%

Music and words in the visual cortex: The impact of musical expertise

Mongelli

Dehaene

Vinckier

et al. 2017

Cortex

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How does the human visual system accommodate expertise for two simultaneously acquired symbolic systems? We used fMRI to compare activations induced in the visual cortex by musical notation, written words and other classes of objects, in professional musicians and in musically naïve controls. First, irrespective of expertise, selective activations for music were posterior and lateral to activations for words in the left occipitotemporal cortex. This indicates that symbols characterized by different visual features engage distinct cortical areas. Second, musical expertise increased the volume of activations for music and led to an anterolateral displacement of word-related activations. In musicians, there was also a dramatic increase of the brain-scale networks connected to the music-selective visual areas. Those findings reveal that acquiring a double visual expertise involves an expansion of category-selective areas, the development of novel longdistance functional connectivity, and possibly some competition between categories for the colonization of cortical space.

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A number-form area in the blind

Cited by 111 publications

References 68 publications

Mapping human temporal and parietal neuronal population activity and functional coupling during mathematical cognition

Mapping human temporal and parietal neuronal population activity and functional coupling during mathematical cognition

Left cortical specialization for visual letter strings predicts rudimentary knowledge of letter-sound association in preschoolers

Music and words in the visual cortex: The impact of musical expertise

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