My research focusses on wireless, extrasynaptic communication by neuropeptide messengers in the nervous system. In my group at KU Leuven, we aim to understand how the neuropeptide signalling network in the brain is organised and how it controls behavioural plasticity, such as learning. We investigate these questions in the compact and defined nervous system of Caenorhabditis elegans by mapping the neuropeptide-receptor network at the biochemical and circuit levels. We use large-scale pharmacological approaches to characterise receptor-ligand interactions and signalling pathways. We are also developing genetically encoded peptide sensors and combining these tools with behavioural analysis to study the spatiotemporal dynamics and functions of neuropeptide signalling in behaviour. At the LMB, we have collaborated closely to uncover principles of neuropeptide network organisation at the brain scale. In particular, with Bill Schafer’s group, we have mapped the neuropeptide signalling network across the entire nervous system of C. elegans by integrating peptide-GPCR interactions with gene expression profiles of each neuron class. This work generated the first brain-wide neuropeptide connectome compiled in any animal. The mapping of this network allows us to address how the structure of the neuropeptide network relates to brain function and could serve as a prototype for understanding peptide networks in larger brains.