Florence Bouhali

A growing body of literature indicates strong associations between indentations of the cerebral cortex (i.e., sulci) and individual differences in cognitive performance. Interruptions, or gaps, of sulci (historically known as pli de passage) are particularly intriguing as previous work suggests that these interruptions have a causal effect on cognitive development. Here, we tested how the presence and morphology of sulcal interruptions in the left posterior occipitotemporal sulcus (pOTS) longitudinally impact the development of a culturally-acquired skill: reading. Forty-three children were successfully followed from age 5 in kindergarten, at the onset of literacy instruction, to ages 7 and 8 with assessments of cognitive, pre-literacy, and literacy skills, as well as MRI anatomical scans at ages 5 and 8. Crucially, we demonstrate that the presence of a left pOTS gap at 5 years is a robust and relatively specific longitudinal predictor of better future reading skills in children, with large observed benefits on reading behavior ranging from pseudoword decoding to reading comprehension. The effect of left pOTS interruptions on reading acquisition accumulated through time and showed strong predictive power relative to benchmark cognitive and familial predictors of reading ability and disability. Finally, we show that increased local U-fiber white matter connectivity associated with such sulcal interruptions possibly underlie these behavioral benefits, by providing a computational advantage. To our knowledge, this is the first quantitative evidence supporting a potential integrative gray-white matter mechanism underlying the cognitive benefits of macro-anatomical differences in sulcal morphology related to longitudinal improvements in a culturally-acquired skill.

Purpose: Children’s reading development is shaped through a complex interplay of genetic and environmental influences within families. This exploratory study investigated the intergenerational transmission of reading achievement within biological families. Prior studies have often measured different constructs in parents and children; many have included only mothers in models; and few have examined whether transmission varies by parent and child sex. We systematically examined whether parent-child associations in reading achievement varied by reading subcomponent, parent sex, and child sex. Method: Participants included 80 families (mother, father, child[ren] aged 7–12 years; n = 267). All participants completed identical standardized assessments across four reading subcomponents. Sex-stratified linear mixed models were used to estimate associations by parent and child sex, with shared reading explored as a mediator. Results: Sex-discordant dyads (father-daughter, mother-son) exhibited statistically significant associations across passage comprehension, reading fluency, and phonemic decoding efficiency, with sight word reading efficiency showing consistent trends but non-significant associations. Direct coefficients in significant sex-discordant dyads ranged from b = 0.49 to b = 0.89 (standard score units), with 99-100% sign stability under Monte Carlo cross-validation. Sex-concordant dyads showed non-significant associations. Permutation-based contrasts indicated that differences between sex-concordant and sex-discordant dyads were significant for passage comprehension, with suggestive evidence (confidence intervals excluding 0) for phonemic decoding. Shared reading did not significantly mediate associations. Conclusion: Observed associations were numerically stronger between children and opposite-sex parents, challenging assumptions of uniform transmission by dyad type. Passage comprehension and sentence reading fluency showed strongest similarity, while associations for sight word reading were weak. These exploratory findings underscore the importance of measure selection and the consideration of sex as a biological variable in familial control research.

Le cortex visuel ventral chez l’homme se compose d’une mosaïque de régions spécialisées dans la reconnaissance de différentes catégories d’objets. Selon une organisation reproductible, certaines régions répondent préférentiellement aux visages, alors que d’autres sont plus activées par les maisons et les lieux, par les outils, ou encore par les parties du corps. Plusieurs facteurs ont été invoqués pour expliquer la préférence d’une région pour une catégorie donnée, tels que des biais pour le traitement de certaines caractéristiques visuelles (préférence pour la position fovéale ou périphérique des stimuli, pour leur fréquence spatiale haute ou basse), le degré d’exposition et d’expertise (expertise pour les voitures par exemple), ou la connectivité anatomique vers des réseaux cérébraux spécialisés dans le traitement d’un domaine particulier. Chez les enfants, l’apprentissage de la lecture de mots ou d’autres systèmes symboliques culturels provoque le développement de régions corticales dédiées, telles que l’aire de la forme visuelle des mots (VWFA), au sein d’une voie ventrale en partie déjà stabilisée. Ce développement ontologique tardif pour la reconnaissance de symboles, indépendamment de contraintes phylogénétiques propres à la lecture, facilite l’étude de ce qui façonne la spécialisation fonctionnelle au sein de la voie ventrale. Dans cette thèse, nous avons étudié la représentation des mots et des partitions de musique au sein du cortex visuel ventral en combinant des méthodes d’imagerie par résonance magnétique fonctionnelle et de diffusion, à des taches comportementales. D’abord, nous montrons que la localisation de la VWFA chez les adultes correspond, en comparaison à des régions voisines du cortex ventral, à une région connectée de manière optimale à celles du langage qui traitent le contenu sémantique et phonologique. Ensuite, nous montrons que les régions ventrales qui sous-tendent le décodage orthographique sont fonctionnellement hétérogènes selon un axe latero-médial. Les régions médianes semblent encoder les graphèmes de façon sérielle, sous le contrôle de régions pariétales, pour les convertir en phonèmes. A l’inverse, les régions latérales traitent les mots de façon plus flexible pour accéder au lexique. Ces études mettent en évidence le rôle majeur de la connectivité anatomique dans le développement d’une spécialisation fonctionnelle pour les mots, avec la contribution de connectivités diverses qui participent à l’hétérogénéité fonctionnelle du système de la forme visuelle des mots. Enfin, nous observons que la maîtrise de la lecture musicale a d’importantes conséquences sur la latéralisation ventrale d’autres catégories. D’une part, la latéralisation à gauche augmente dans des régions latérales ventrales pour toutes les catégories. D’autre part, la latéralisation à droite augmente dans des régions fusiformes postérieures, notamment pour le traitement des visages et des maisons. Ces conséquences, similaires à celles provoquées par l’apprentissage de la lecture de mots, révèlent des processus à la fois de compétition et de transfert entre catégories. Ainsi, nos résultats suggèrent que des mécanismes communs pourraient expliquer comment une expertise culturelle peut recycler et modifier le cortex visuel.

This study examines whether auditory cortex anatomy reflects multilingual experience, specifically individuals’ phonological repertoire. Using data from over 200 participants exposed to 1–7 languages across 36 languages, we analyzed the role of language experience and typological distances between languages they spoke in shaping neural signatures of multilingualism. Our findings reveal a negative relationship between the thickness of the left and right second transverse temporal gyrus (TTG) and participants’ degree of multilingualism. Models incorporating phoneme-level information in the language experience index explained the most variance in TTG thickness, suggesting that a more extensive and more phonologically diverse language experience is associated with thinner cortices in the second TTG. This pattern, consistent across two datasets, supports the idea of experience-driven pruning and neural efficiency. Our findings indicate that experience with typologically distant languages appear to impact the brain differently than those with similar languages. Moreover, they suggest that early auditory regions seem to represent phoneme-level cross-linguistic information, contrary to the most established models of language processing in the brain, which suggest that phonological processing happens in more lateral posterior superior temporal gyrus (STG) and superior temporal sulcus (STS).

The transition from pre-reading to early word reading skill in early childhood is a time of profound developmental change. To understand changes in brain wiring associated with reading development, this study examined individual differences in functional connectivity of the reading network at the start of formal literacy instruction. Sixty-six kindergarteners (ages 5-6) completed a visual word processing task during functional magnetic resonance imaging (fMRI). Based on standardized literacy assessments, participants were characterized as Pre-Readers (alphabetic knowledge but unable to read words) or Beginning Readers (some word reading ability). We compared patterns of task-based functional connectivity between children at different stages of literacy development using confirmatory subgroup Group Iterative Multilevel Model Estimation (cs-GIMME). cs-GIMME is a data-driven method that estimates directed, time-indexed, and individualized network connections between a priori regions of interest. Pre- and Beginning Readers did not differ in overall network complexity (number of functional connections between regions of interest). However, distinct periods of reading development corresponded to differences in network centrality, defined as the proportion of network connections involving specific regions of interest. Specifically, Pre-Readers had more distributed connections and greater within-right hemisphere connectivity. Beginning Readers demonstrated more symmetrical network organization, and greater centrality of the Visual Word Form Area and other left hemisphere language hubs. Increased reading skill was associated with increased left lateralization, potentially reflecting more mature networks and greater print processing efficiency. These findings provide novel insights into child brain development during the first year of formal schooling by revealing links between emerging literacy skills and functional neural connectivity.

A growing body of literature indicates strong associations between indentations of the cerebral cortex (i.e., sulci) and individual differences in cognitive performance. Interruptions, or gaps, of sulci (historically known as pli de passage) are particularly intriguing as previous work suggests that these interruptions have a causal effect on cognitive development. Here, we tested how the presence and morphology of sulcal interruptions in the left posterior occipitotemporal sulcus (pOTS) longitudinally impact the development of a culturally-acquired skill: reading. Forty-three children were successfully followed from age 5 in kindergarten, at the onset of literacy instruction, to ages 7 and 8 with assessments of cognitive, pre-literacy, and literacy skills, as well as MRI anatomical scans at ages 5 and 8. Crucially, we demonstrate that the presence of a left pOTS gap at 5 years is a specific and robust longitudinal predictor of better future reading skills in children, with large observed benefits on reading behavior ranging from letter knowledge to reading comprehension. The effect of left pOTS interruptions on reading acquisition accumulated through time, and was larger than the impact of benchmark cognitive and familial predictors of reading ability and disability. Finally, we show that increased local U-fiber white matter connectivity associated with such sulcal interruptions possibly underlie these behavioral benefits, by providing a computational advantage. To our knowledge, this is the first quantitative evidence supporting a potential integrative gray-white matter mechanism underlying the cognitive benefits of macro-anatomical differences in sulcal morphology related to longitudinal improvements in a culturally-acquired skill.

A growing body of literature indicates strong associations between indentations of the cerebral cortex (i.e., sulci) and individual differences in cognitive performance. Interruptions, or gaps, of sulci (historically known as pli de passage ) are particularly intriguing as previous work suggests that these interruptions have a causal effect on cognitive development. Here, we tested how the presence and morphology of sulcal interruptions in the left posterior occipitotemporal sulcus (pOTS) longitudinally impact the development of a culturally-acquired skill: reading. Forty-three children were successfully followed from age 5 in kindergarten, at the onset of literacy instruction, to ages 7 and 8 with assessments of cognitive, pre-literacy, and literacy skills, as well as MRI anatomical scans at ages 5 and 8. Crucially, we demonstrate that the presence of a left pOTS gap at 5 years is a specific and robust longitudinal predictor of better future reading skills in children, with large observed benefits on reading behavior ranging from letter knowledge to reading comprehension. The effect of left pOTS interruptions on reading acquisition accumulated through time, and was larger than the impact of benchmark cognitive and familial predictors of reading ability and disability. Finally, we show that increased local U-fiber white matter connectivity associated with such sulcal interruptions possibly underlie these behavioral benefits, by providing a computational advantage. To our knowledge, this is the first quantitative evidence supporting a potential integrative gray-white matter mechanism underlying the cognitive benefits of macro-anatomical differences in sulcal morphology related to longitudinal improvements in a culturally-acquired skill.

Efficient reading requires a fast conversion of the written word to both phonological and semantic codes. We tested the hypothesis that, within the left occipitotemporal cortical regions involved in visual word recognition, distinct subregions harbor slightly different orthographic codes adapted to those 2 functions. While the lexico-semantic pathway may operate on letter or open-bigram information, the phonological pathway requires the identification of multiletter graphemes such as “ch” or “ou” in order to map them onto phonemes. To evaluate the existence of a specific stage of graphemic encoding, 20 adults performed lexical decision and naming tasks on words and pseudowords during functional MRI. Graphemic encoding was facilitated or disrupted by coloring and spacing the letters either congruently with multiletter graphemes (ch-ai-r) or incongruently with them (c-ha-ir). This manipulation affected behavior, primarily during the naming of pseudowords, and modulated brain activity in the left midfusiform sulcus, at a site medial to the classical visual word form area (VWFA). This putative grapheme-related area (GRA) differed from the VWFA in being preferentially connected functionally to dorsal parietal areas involved in letter-by-letter reading, while the VWFA showed effects of lexicality and spelling-to-sound regularity. Our results suggest a partial dissociation within left occipitotemporal cortex: the midfusiform GRA would encode orthographic information at a sublexical graphemic level, while the lateral occipitotemporal VWFA would contribute primarily to direct lexico-semantic access.