Presentation
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Innate neural mechanisms underlying semantic cognition: converging evidences from neonate and twin studies
Poster A98 in Poster Session A, Tuesday, October 24, 10:15 am - 12:00 pm CEST, Espace Vieux-Port
Ziliang Zhu1, Huichao Yang1, Haojie Wen1, Yueqin Hu1, Yanchao Bi1,2, Xi Yu1; 1Beijing Normal University, 2Chinese Institute for Brain Research
Introduction: The anterior part of human temporal cortex, the temporal pole (TP), plays an important role in the neural bases underlying semantic representation in adults. Previous studies suggested functional subdivisions in the TP, with each connecting to different brain networks, supporting the integration of knowledge derived from various domains, including language and sensory/vision. Here, we utilized data from Human Connectome Project (HCP) and developing Human Connectome Project (dHCP) to examine the ontogenetic origins of functional subdivision in TP. Methods & Results: 1) Using a K-means clustering approach, a three-subdivision structure of TP (dorsal, dTP; lateral, lTP; and ventral, vTP) was identified in adults (N=100, 55 females, 28.3 ± 3.4 years old) based on their whole-brain resting-state functional connectivity (FC) patterns of TP. Subsequent seed(subdivision)-based FC analyses revealed specific FC patterns of each subdivision. That is, compared to other subdivisions, the dTP more strongly connected with the language network (ts > 5.23, ps < 0.001); the lTP with the default network (ts > 15.31, ps < 0.001); and the vTP with the sensory system (ts > 3.30, ps < 0.003). 2) The same clustering method further revealed an adult-like three-subdivision structure of TP in neonates (N=150, 69 females, 1.25 ± 1.15 weeks old, mean Dice coefficients between neonatal and adult TP subdivisions = 0.76). Moreover, similar to adults, the neonatal brain showed stronger FCs between the dTP and the language network (ts > 11.16, ps < 0.001), as well as between the lTP and the default network (ts > 5.12, ps < 0.001). However, the vTP in neonatal brain did not show the specific FC patterns with sensory system (ps > 0.9). 3) Finally, the heritable patterns of the specific FC of TP subdivisions were examined in the adult twin participants available in the HCP dataset. The subdivision-specific FC was quantified as FC between each subdivision and its preferred system (e.g., dTP with the language system) minus the mean FC between the same system and the other two subdivisions (e.g., lTP and vTP with the language system). The quantitative genetic analyses revealed significant genetic effects on the specific FC of dTP and lTP both when participants were at rest (123 monozygotic pairs and 67 dizygotic pairs; ps < 0.001) and performing a semantic task (i.e., story-comprehension, 129 monozygotic pairs and 71 dizygotic pairs; ps < 0.05). No reliable genetic effects were observed for the specific FC of vTP in either status of participants. Summary: The current findings demonstrated that the adult-like FC-based subdivisions of TP were already present in neonates. Combined with the specific connectivity patterns of dTP and lTP that were early-emerging and genetically programmed, these results suggest innate functional connectivity mechanisms in TP that support its integrative role in the human semantic network. Moreover, our results also highlight the importance of postnatal experiences on the development of neural networks for semantic processing, especially for vTP whose specific connection patterns were mostly environmentally influenced and only observed in adults.
Topic Areas: Language Development/Acquisition,