Synaptic connectome of a neurosecretory network in the <i>Drosophila</i> brain

Hormones regulate communication between different organs, influencing various functions like sleep, feeding, growth, metabolism, and reproduction. In insects, the pars intercerebralis and pars lateralis serve as central locations for neurosecretory cells (NSCs) that generate different peptide hormones. Researchers aimed to understand how hormonal signaling is controlled by mapping the synaptic connectome of NSCs in the adult Drosophila brain.

It was found that diuretic hormone 44-producing NSCs play a key role in coordinating physiology and behavior. Despite most NSCs having dendrites in the subesophageal zone, responsible for primary taste processing, most sensory neurons connect to NSCs indirectly. The study also uncovered how various olfactory inputs are relayed to NSCs.

By applying a measure of influence based on linear dynamical systems, enteric neurons emerged as the most potent drivers of NSC activity compared to other sensory inputs. Additionally, descending neurons from the brain were identified as significant regulators of NSC activity, controlling both endocrine and motor outputs to align physiological changes with appropriate behaviors.

NSC inputs were sparse, mainly facilitated by corazonin-producing NSCs, with these cells also impacting egg-laying through their downstream synaptic partners. The research extended to examine potential indirect connections between NSC classes and peptide hormone pathways that affect peripheral tissues, utilizing single-cell transcriptomic data.

This detailed mapping of the Drosophila neurosecretory network connectome offers a foundation for exploring intricate hormonal networks and their role in shaping animal behaviors and physiology.