Integration of audiovisual danger stimuli in the zebrafish tectum is linked with premotor and behavioral enhancements

Multisensory integration enables animals to combine sensory cues, enhancing threat detection and escape behaviors. Although the Tectum is traditionally considered a visual center, its role in integrating auditory and visual danger signals is not fully understood. Using in vivo calcium imaging in larval zebrafish, we demonstrate that auditory stimuli recruit a significant population of tectal neurons, mainly in deep layers. Visual looms elicit strong tectal responses, but combined auditory-visual stimuli robustly increase neural activity and the likelihood of rapid escape, especially for less salient cues engaging more tectal neurons than unisensory stimuli. 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, connecting tectal integration to premotor circuits that drive behavioral output. Our findings provide a mechanistic basis for tectal multisensory processing in enhancing behavioral escape responses.