Connectomic Organization of the Suprachiasmatic Nucleus

Liu, J.; Yu, J.; Shen, L.; Chen, X.; Ma, L.; Zhai, H.; Li, L.; Zhang, L.; Wang, L.; Yuan, J.; Chen, B.; Hong, B.; Lv, Y.; Cai, Y.; Zhang, Y.; Chang, S.; Guo, J.; Chen, H.; Liu, M.; Wang, Z.; Xin, T.; Zhou, F.; Zhao, X.; Zhang, D.; Xie, Q.; Ma, H.; Xu, Y.; Cheng, H.; Han, H.

doi:10.1101/2024.10.20.619252

bioRxiv · 10.1101/2024.10.20.619252

Connectomic Organization of the Suprachiasmatic Nucleus

Liu, J.·Yu, J.·Shen, L.·Chen, X.·Ma, L.·Zhai, H.·Li, L.·Zhang, L.·Wang, L.·Yuan, J.·Chen, B.·Hong, B.·Lv, Y.·Cai, Y.·Zhang, Y.·Chang, S.·Guo, J.·Chen, H.·Liu, M.·Wang, Z.·Xin, T.·Zhou, F.·Zhao, X.·Zhang, D.·Xie, Q.·Ma, H.·Xu, Y.·Cheng, H.·Han, H.

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Abstract

The suprachiasmatic nucleus (SCN), the mammalian master clock, is a special structure dedicated to the time computation. However, a connectomic understanding of the nucleus as a whole is lacking. Using serial section electron microscopy, we reconstructed multiscale and multimodal SCN communication networks. Intra-SCN synaptic network consists of 9,566 morphologically similar neurons and 4.3 million synapses, organized into multiscale circuitries that interact with SCN-traversing axon fascicles. Strikingly, SCN neurons engage in unique soma-soma ephaptic interaction, forming 2,038 electrotonic integrative units with the largest overlapping the light-responsive area (LRA). SCNs paracrine modality contains 47,396 m3 dense core vesicles, with notable scarcity in the LRA, suggesting cross-modal coordination and functional integration. These distinct network features provide comprehensive insights into the system architecture of the mammalian circadian clock.

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Liu, J., Yu, J., Shen, L., Chen, X., Ma, L., Zhai, H., Li, L., Zhang, L., Wang, L., Yuan, J., Chen, B., Hong, B., Lv, Y., Cai, Y., Zhang, Y., Chang, S., Guo, J., Chen, H., Liu, M., Wang, Z., Xin, T., Zhou, F., Zhao, X., Zhang, D., Xie, Q., Ma, H., Xu, Y., Cheng, H., Han, H.. 2024-10-22. Connectomic Organization of the Suprachiasmatic Nucleus. https://doi.org/10.1101/2024.10.20.619252

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