Behavioral responses result from changes in neurons and neural circuits. The properties of neural circuits can be altered by neurochemical signals known as neuromodulators. Unlike classical neurotransmitters, neuromodulators can act beyond synaptic connections and be transported through volume transmission, allowing them to influence cells positioned at a distance from one another.

Neuropeptides represent a diverse group of neuromodulators. These short peptides primarily exert their effects by binding to G protein-coupled receptors (GPCRs), which themselves exhibit significant functional diversity. The interactions between neuropeptides and their receptors provide a versatile mechanism for modulating neural circuits. Such modifications have been shown to shape behavioral plasticity across multiple species. However, we are only beginning to understand the mechanisms by which neuropeptides regulate neural circuits that control locomotion, feeding, mating, and learning behaviors. Recent advancements in tools and technologies for investigating the biochemistry, anatomical localization, and function of neuropeptide-receptor interactions have created new opportunities to explore how these signaling pathways modulate neural circuits in diverse experimental systems.

This Methods Collection aims to showcase recent developments in these investigative tools across a range of experimental models, including but not limited to Platynereis, C. elegans, Drosophila, and mammalian systems. The collection will highlight advances in light and electron microscopy, biochemistry, high-throughput screening, and computational modeling, providing insights into the evolving methodologies used to study neuropeptide function in neural circuit modulation.