Biology subjects

Charng, C.-C.

Publications and source records attributed to Charng, C.-C..

4 recordsLinked to original sources

bioRxiv2026

High-resolution volumetric intravital imaging reveals asymmetric serotonin-dependent post-shock activity in the Drosophila brain

Volumetric intravital imaging of adult Drosophila brains remains challenging due to optical scattering and speed limitations of conventional microscopy. Here, we present V-shape Bessel-beam light-sheet microscopy (vSPIM), an upright, high-speed platform achieving subcellular resolution across large, opaque volumes in vivo. Through real-time calcium imaging in adult Drosophila, vSPIM uncovered two unprecedented phenomena: first, a complex ensemble of approximately 150 olfactory projection neuron boutons (more than 400 per hemisphere) resolved 18 distinct odor valence coding patterns within the dense mushroom body calyx, aligning with connectomic architecture. Second, vSPIM revealed a previously uncharacterized asymmetric, serotonin-dependent post-shock firing (PsF) response. This PsF activity emerged within the mushroom body and dopaminergic neurons only after repetitive aversive stimulation, distinct from canonical dopamine-driven reinforcement signals. Finally, we demonstrated the versatility of vSPIM by tracking corneal endothelial dynamics during mouse wound healing. Overall, vSPIM establishes a scalable framework for intravital imaging, bridging the gap between optical innovation and circuit physiology in adult tissues.

neuroscience↗

bioRxiv2026

Dopaminergic Modulation of Mushroom Body Output Neurons Mediates Nociception-Induced Escape in Drosophila

In Drosophila, noxious heat is detected by peripheral nociceptors expressing transient receptor potential (TRP) channels, including Painless and TrpA1, and rapidly triggers escape behavior. Although peripheral transduction has been defined in detail, the central circuits and neuromodulatory mechanisms that translate nociceptor activity into escape decisions remain poorly understood. Here, we combine targeted behavioral perturbations with anatomical tracing to delineate a nociception-to-escape pathway that engages dopaminergic modulation of mushroom body (MB) output. Kir2.1-mediated silencing across candidate neurotransmitter systems revealed a specific requirement for MB-innervating dopaminergic neurons (DANs)--particularly subsets within the protocerebral posterior lateral 1 (PPL1) and protocerebral anterior medial (PAM) clusters--for robust nociception-induced escape. Anterograde trans-Tango tracing from painless- and trpA1-expressing nociceptors labeled these MB dopaminergic neurons as direct postsynaptic partners, consistent with convergence of distinct nociceptor inputs onto a shared dopaminergic pathway. Finally, silencing a subset of mushroom body output neurons (MBONs) delayed escape without overtly disrupting baseline locomotion, supporting a model in which dopaminergic signaling recruits MB output to shape defensive action selection. Together, our results define a multi-layer circuit motif linking peripheral nociception to MB-dependent escape and provide a framework for dissecting how neuromodulation gates rapid defensive behaviors.

neuroscience↗

bioRxiv2024

Unique Asymmetric Branching of Drosophila Neurons Optimizes Temporal Dendritic Computation

Neurons execute a versatile array of computations through a complex interplay of factors, including their morphology and synaptic architecture. Dendritic branching encodes upstream inputs into diverse spike patterns transmitted via downstream axons. While earlier studies highlighted the distinct morphologies and functions of a few representative neurons, the availability of large-scale electron microscopy and fluorescent imaging now enables comprehensive data analysis and further simulations to explore structure-function relationships more broadly. This study investigates the general morphological characteristics of diverse neuron types in the fly model. By employing the Strahler Order (SO) metric, we identified a specific bias towards asymmetry in neuronal branching and further investigated the effect of the asymmetry on computational capabilities. Specifically, symmetric branching enhances coincidence detection capability, whereas asymmetric branching increases input order-selectivity. While certain neurons exhibit extreme symmetry or asymmetry optimized for specific tasks, most neurons strike a balance between these computational strategies. This balance underscores the intricate relationship between neuronal structure and function. In contrast to the wide range of branching symmetries found in random bifurcation models, neurons across different species exhibit species-specific asymmetry, suggesting shared underlying branching mechanisms. Our findings provide a fresh perspective on the exploration of neuronal morphologies and their computational roles. Significance StatementThis study reveals a novel structure-function relationship by analyzing the asymmetric branching patterns of fly neurons using extensive morphological data. While certain neurons display extreme symmetry or asymmetry for specialized computational roles, most converge toward a characteristic degree of asymmetry to balance their computational demands, especially in larger branching structures. This suggests that neuronal branching may be governed by intrinsic principles that support both developmental and functional needs.

neuroscience↗

bioRxiv2023

Hybrid Neural Networks of the Olfactory Learning Center in the Drosophila Brain

Biological signal encoding is shaped by the underlying neural circuitry. In Drosophila melanogaster, the mushroom body (MB) houses thousands of Kenyon cells (KCs) that process olfactory signals from hundreds of projection neurons (PNs). Previous studies debated the connectivity between PNs and KCs (random vs. structured). Our multiscale analysis of electron microscopic data revealed a hybrid network with diverse synaptic connection preferences and input divergence across different KC classes. Using MB connectome data, our simulation model, validated via functional imaging, accurately predicted distinct chemical sensitivities in the major KC classes. The model suggests that the hybrid network excels in detecting food odors while maintaining precise odor discrimination in different KC classes. These findings underscore the computational advantages of this hybrid network.

neuroscience↗