Integration of Audiovisual Danger Stimuli in the Zebrafish Tectum is Linked with Premotor and Behavioral Enhancements

Multisensory integration allows animals to combine cues from different sensory modalities to improve threat detection and drive evasive behaviors. While the zebrafish Tectum is classically viewed as a visual processing center, its role in integrating auditory and visual danger signals remains unclear. Using in vivo calcium imaging in larval zebrafish, we find that brief, high-amplitude auditory stimuli recruit a significant population of tectal neurons, predominantly in deep tectal layers. While visual looms produce strong responses in the zebrafish Tectum, combined auditory and visual stimuli robustly increases both tectal neural activity and the probability of executing rapid escape maneuvers, especially for low salient stimuli. Interestingly, simultaneous auditory and visual cues engage more tectal neurons than either modality alone. Single neuron analysis reveals a population of neurons that respond to both auditory and visual cues, and importantly, shows that a proportion of those neurons only responds to multisensory stimulation. These results establish the zebrafish Tectum as a multisensory processing area. Notably, the heightened tectal response during multisensory stimulation is strongly correlated with increased activity in hindbrain neurons implicated in escape-like motion events. These results link tectal multisensory integration to premotor circuits that drive behavioral output. Overall, our findings reveal the zebrafish Tectum as a hub for integration of audiovisual threat signals and provide a mechanistic basis for tectal multisensory processing in enhancing behavioral escape responses.