Biology subjects

Katzner, S.

Publications and source records attributed to Katzner, S..

3 recordsLinked to original sources

bioRxiv2026

Ethological variability shapes the structure and content of sensory population codes

Established theories of sensory coding posit that sensory systems are adapted to the statistics of natural stimuli that originate in the external environment. In natural, ethological conditions, however, sensory populations are simultaneously influenced by multiple modulatory processes. During behavior, the statistics of population responses already at the sensory periphery reflect not only external signals, but also internal and behavioral states such as locomotion, attention, and arousal. Theories of sensory coding in real-world conditions must therefore explain adaptation not only to natural scenes, but also to the structured variability induced by these internal processes and behavior. Here, we investigated population activity in the dorsal lateral geniculate nucleus (dLGN), a critical early stage of the visual pathway. Using a simple probabilistic model and information-theoretic approaches, we characterized this variability through the statistics of the population messages conveyed downstream. Our results show that population variability is multidimensional: even when one behavioral factor is constant, responses can vary substantially as other modulatory factors fluctuate. Under natural conditions, sensory population codes can therefore change their statistical structure and content, i.e., the stimulus features they encode along multiple dimensions simultaneously. These findings highlight the need for sensory coding theories that account not only for adaptation to natural stimuli, but also to the statistics of internal and behavioral states.

neuroscience↗

bioRxiv2024

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

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.

neuroscience↗

bioRxiv2016

Learning enhances sensory processing in mouse V1 before improving behavior

A fundamental property of visual cortex is to enhance the representation of those stimuli that are relevant for behavior, but it remains poorly understood how such enhanced representations arise during learning. Using classical conditioning in mice, we show that orientation discrimination is learned in a sequence of distinct behavioral stages, in which animals first rely on stimulus appearance before exploiting its orientation to guide behavior. After confirming that orientation discrimination under classical conditioning requires primary visual cortex (V1), we measured, during learning, response properties of V1 neurons. Learning improved neural discriminability, sharpened orientation tuning and led to higher contrast sensitivity. Remarkably, these learning-related improvements in the V1 representation were fully expressed before successful orientation discrimination was evident in the animals behavior. We propose that V1 plays a key role early in discrimination learning to enhance behaviorally relevant sensory information.

neuroscience↗