Biology subjects

Sarre, A.

Publications and source records attributed to Sarre, A..

3 recordsLinked to original sources

bioRxiv2026

Early sensory deprivation drives local reorganization of sensory integration within a conserved global hierarchy

The human brain processes sensory information through a hierarchical system, from primary to higher-level regions, integrating inputs across modalities to support perception and cognition. While early sensory loss triggers widespread neuroplastic changes, its impact on integration across the cortical hierarchy remains unclear. Here, we examined the cortical reorganization of individuals with early blindness and deafness using a sensory integration framework that quantifies how brain regions prioritize different sensory inputs across the hierarchy. We found that early sensory deprivation drives highly localized reorganization adjacent to the deprived primary cortical areas: extrastriate cortex in early blindness and the superior temporal cortex in early deafness. These findings were further corroborated by analysis of the functional gradients, which found reorganization within these sensory regions. Notably, the hierarchy was largely preserved across groups. However, the sensory integration framework uniquely detected reorganization in language-related regions in deaf individuals with knowledge of a visual communication system known as cued speech. The specific differences between early deaf and hearing individuals remained restricted to superior temporal cortex. Together, our findings demonstrate that early sensory deprivation drives targeted reorganization adjacent to the affected primary sensory cortex, while preserving the overall hierarchy of cortical integration.

neuroscience↗

bioRxiv2024

Seeing speech: neural mechanisms of cued speech perception in prelingually deaf and hearing users

For many deaf people, lip-reading plays a major role in verbal communication. However, lip movements are by nature ambiguous, so that lip reading does not allow for a full understanding of speech. The resulting language access difficulties may have serious consequences on language, cognitive and social development. Cued speech (CS) was developed to eliminate this ambiguity by complementing lip-reading with hand gestures, giving access to the entire phonological content of speech through the visual modality alone. Despite its proven efficiency for improving linguistic and communicative abilities, the mechanisms of CS perception remain largely unknown. The goal of the present study is to delineate the brain regions involved in cued speech perception and identify their role in visual and language-related processes. Three matched groups of participants were scanned during two fMRI experiments: Prelingually deaf users of cued speech, hearing users of cued speech, and naive hearing controls. In Experiment 1, we presented videos of silent CS sentences, isolated lip movements, isolated gestures, plus CS sentences with speech sounds and meaningless CS sentences. In Experiment 2, we presented pictures of faces, bodies, written words, tools, and houses in order to understand the contribution of category-specific visual regions to CS perception. We delineated a number of mostly left-hemisphere brain regions involved in CS perception. We first found that language areas were activated in all groups by both silent CS sentences and isolated lip movements, and by gestures in deaf participants only. Despite overlapping activations when perceiving CS, several findings differentiated experts from novices. As such, CS expertise was associated with a leftward functional lateralization of the lateral occipital cortex, possibly driven by the expert identification of hand gestures. The Visual Word Form Area, which supports the interface between vision and language during reading, did not contribute to CS perception. Moreover, the integration of lip movements and gestures took place in a temporal language-related region in deaf users, and in movement-related regions in hearing users, reflecting their different profile of expertise in CS comprehension and production. Finally, we observed a strong involvement of the Dorsal Attentional Network in hearing users of CS, and identified the neural correlates of the variability in individual proficiency. Cued speech constitutes a novel pathway for accessing core language processes, halfway between speech perception and reading. The current study provides a delineation of the common and specific brain structures supporting those different modalities of language input, paving the way for further research.

neuroscience↗

bioRxiv2022

The lncRNA Sweetheart regulates compensatory cardiac hypertrophy after myocardial injury

After myocardial infarction in the adult heart the remaining, non-infarcted tissue adapts to compensate the loss of functional tissue. This adaptation requires changes in gene expression networks, which are mostly controlled by transcription regulating proteins. Long non-coding transcripts (lncRNAs) are now recognized for taking part in fine-tuning such gene programs. We identified and characterized the cardiomyocyte specific lncRNA Sweetheart RNA (Swhtr), an approximately 10 kb long transcript divergently expressed from the cardiac core transcription factor coding gene Nkx2-5. We show that Swhtr is dispensable for normal heart development and function, but becomes essential for the tissue adaptation process after myocardial infarction. Re-expressing Swhtr from an exogenous locus rescues the Swhtr null phenotype. Genes depending on Swhtr after cardiac stress are significantly occupied, and therefore most likely regulated by NKX2-5. Our results indicate a synergistic role for Swhtr and the developmentally essential transcription factor NKX2-5 in tissue adaptation after myocardial injury.

developmental biology↗