Neuronal assembly dynamics and behavior in the zebrafish habenula.

Neural activity is not random but displays sparse, organized spatiotemporal patterns, even in the absence of structured external stimulation. Neuronal assemblies, defined as populations of co-activated neurons, have been proposed as fundamental units of neural computation underlying processes such as perception, memory, and behavior. However, their biological relevance and functional significance remain poorly understood. We use calcium imaging to record spontaneous activity in the habenula and identified neuronal assemblies using a PCA based pipeline. In larval zebrafish, we observed repeated, temporally structured patterns of network activity and began investigating how these assemblies change across early developmental stages and whether they are shaped by experience-dependent factors such as social isolation. We also explore their involvement in the response to auditory and visual stimuli. More recently, we developed an approach to simultaneously monitor behavior during calcium imaging, allowing us to directly relate neural assembly dynamics to ongoing behavior. By comparing freely moving larvae with agarose-embedded animals imaged under the microscope, we aim to determine how social isolation influences spontaneous and stimulus-evoked network activity at both the behavioural and neuronal level simultaneously.