A hemispheric dome setup for naturalistic visual stimulation in head-fixed mice

Abstract

The visual system of any animal species is adapted to its ecological niche. Thus, investigating visual function and behavior using naturalistic stimuli holds significant potential. In mice, these adaptations include a field of view of [~]280{degrees} and cone opsins sensitive to UV and green wavelengths. Such adaptations, however, cannot be probed with standard consumer displays. To present naturalistic visual stimuli to mice, we built a hemispheric dome setup, enabling the controlled projection of wide-field movies with UV-green spectral content. For our UV-green projection, we used a customized light engine with external high-power LEDs. We mitigated spatial distortions introduced by the projection through a geometry-independent calibration procedure. Additionally, we adapted a head-mounted eye tracking system to capture behavioral responses of head-fixed mice viewing these stimuli. We validated our setup by quantifying the pupillary light reflex to uniform stimuli and the optokinetic reflex to drifting gratings. Finally, in experiments with naturalistic movies, we investigated whether mice showed differential saccades and eye positions based on visual input. Comparing naturalistic movies to a uniform screen control condition, we observed that although head-fixed mice did not make targeted saccades during movies, their overall eye position consistently shifted towards more frontal regions of visual space. This indicates that mice adjust their eye position in a stimulus-dependent way, potentially to optimize visual processing of information ahead in the visual field. Together, our results highlight the utility of our setup for in vivo studies of the mouse visual system with more naturalistic visual stimulation. Significance StatementOver the past decades, mice have emerged as a prominent model for vision. Nonetheless, compared to primates, mice inhabit a different visual niche, featuring several species-specific adaptations, including a wide field of view and sensitivity to UV light. Both adaptations cannot be adequately studied using consumer displays commonly employed in vision research. We therefore built a hemispheric dome setup allowing the presentation of wide field movies with appropriate spectral content and tracking eye movements and pupil dynamics in head-fixed mice with minimal shadows. We provide a baseline assessment of the setup leveraging two well-established eye reflexes. We also showcase the setups utility by reporting adjustments in eye movements when mice viewed the naturalistic movies.