Distinctive features of the central synaptic organization of Drosophila larval proprioceptors

Frontiers in Neural Circuits

Neural Circuits

Marie R. Greaney¹  Ellie S. Heckscher²  Chris C. Wreden³ 

[1] Committee on Neurobiology, The University of Chicago, Chicago, IL, United States;Committee on Neurobiology, The University of Chicago, Chicago, IL, United States;Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL, United States;Institute for Neuroscience, The University of Chicago, Chicago, IL, United States;Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL, United States;

关键词: proprioception;    somatosensation;    synapses;    connectome;    nociception;   

DOI  :  10.3389/fncir.2023.1223334

 received in 2023-05-16, accepted in 2023-07-07,  发布年份 2023

来源: Frontiers

【 摘 要 】

Proprioceptive feedback is critically needed for locomotor control, but how this information is incorporated into central proprioceptive processing circuits remains poorly understood. Circuit organization emerges from the spatial distribution of synaptic connections between neurons. This distribution is difficult to discern in model systems where only a few cells can be probed simultaneously. Therefore, we turned to a relatively simple and accessible nervous system to ask: how are proprioceptors’ input and output synapses organized in space, and what principles underlie this organization? Using the Drosophila larval connectome, we generated a map of the input and output synapses of 34 proprioceptors in several adjacent body segments (5–6 left-right pairs per segment). We characterized the spatial organization of these synapses, and compared this organization to that of other somatosensory neurons’ synapses. We found three distinguishing features of larval proprioceptor synapses: (1) Generally, individual proprioceptor types display segmental somatotopy. (2) Proprioceptor output synapses both converge and diverge in space; they are organized into six spatial domains, each containing a unique set of one or more proprioceptors. Proprioceptors form output synapses along the proximal axonal entry pathway into the neuropil. (3) Proprioceptors receive few inhibitory input synapses. Further, we find that these three features do not apply to other larval somatosensory neurons. Thus, we have generated the most comprehensive map to date of how proprioceptor synapses are centrally organized. This map documents previously undescribed features of proprioceptors, raises questions about underlying developmental mechanisms, and has implications for downstream proprioceptive processing circuits.

【 授权许可】

Unknown   
Copyright © 2023 Greaney, Wreden and Heckscher.