PERINEURONAL NETS IN THE DEVELOPMENT OF THE ZEBRAFISH BRAIN

Perineuronal nets (PNNs) are specialized extracellular matrix structures that surround specific neuronal populations (e.g., parvalbumin neurons). PNNs participate in regulating brain plasticity and learning across species and play a crucial role in stabilizing synaptic connections and regulating critical periods during brain development. Dysregulation of PNNs is present in neurodevelopmental conditions, including autism spectrum disorder. Zebrafish, as an animal model, offers significant advantages due to its genetic similarities to mammals, transparent larval stage, and early emergence of social behaviors. The localization and developmental patterns of PNNs in the zebrafish brain remain largely uncharacterized. Therefore, understanding the spatial and temporal dynamics of PNNs in zebrafish is a critical first step to explore their potential involvement in social behavior. To visualize the PNN, we collected zebrafish at different developmental stages, from one week post-fertilization to adulthood. The adult brains were fixed and sectioned into coronal, horizontal, and sagittal slices, followed by an immunostaining procedure with CS-56 antibody. The samples were mounted and examined using an LSM980 confocal microscope to characterize PNNs' localization. As a result, PNNs were localized in different regions throughout the zebrafish adult brain, notably within the telencephalon, as well as in other brain regions previously described to contain parvalbumin cells. In conclusion, the zebrafish model appears promising for investigating PNNs and critical period mechanisms.