SPATIO-TEMPORAL ORGANIZATION AND STATE DEPENDENCE OF DORSAL PALLIAL CIRCUITS IN JUVENILE ZEBRAFISH

Adaptive behavior requires neural circuits that can flexibly integrate and transform external signals and internal states. The zebrafish pallium contains molecularly and anatomically defined neuronal populations that resemble mammalian hippocampus, amygdala, and neocortex, making zebrafish a powerful model to dissect conserved forebrain circuit principles. Previous work from our lab has revealed a fine pallial regionalization in the zebrafish dorsal telencephalon, where spatially distinct neuronal ensembles exhibit structured resting-state activity and encode different aspects of sensory experience.
In this study, we investigated the activity of the entire juvenile zebrafish pallium. First, we showed that pallial circuits are spatially organized, such that neurons with similar ongoing activity are clustered into distinct regions that are identifiable across animals. We also observed that distinct pallial regions exhibit ongoing activity with characteristic temporal features that are likewise consistent across animals. We created a transgenic zebrafish line that specifically labels neurons located in a distinct pallial region and molecularly resembling deep-layer mammalian neocortex. These neurons exhibit high levels of resting-state activity both in vivo and ex vivo, and we show that their activity is strongly state dependent but not directly altered by sensory stimulation.
Ongoing work dissects how internal state, local microcircuit architecture, and neuromodulatory influences reconfigure these dorsal pallial dynamics, providing a framework to study state-dependent modulation in a regionally organized vertebrate forebrain.