SFB 1348 Seminar | Marion Silies

Strategies for stable vision in dynamically changing environments

Host: Christian Klämbt

A major challenge for the brain is to keep stable neural representations of visual information while facing a wide range of sensory inputs in natural scenes. Visual systems must stably compute contrast and motion cues, while actively navigating the environment. However, such self-movement of the animal leads to rapid changes in background illumination, and to global motion cues occurring across the animal’s eye. How does the visual system deal with such changes caused by animal behavior? Here, I will discuss how Drosophila stably processes visual information under constantly changing conditions. First, I will talk about changes in luminance that occur rapidly, for example when our eyes saccade across a natural scene, or when the visual input changes at fast time scales due to self-movement of the animal. We have investigated the computational principles, as well as the mechanism that allows flies to handle such changes in illumination present when animals navigate natural visual scenes. Starting from animal behavior, we have identified the underlying neural circuitry, and have developed novel genetic tools to study specific cellular interactions within circuit motifs at unprecedented resolution. Knowing the neural microcircuit motif that ensures stable visual perception then allowed us to also investigate the underlying biophysical mechanism. Stable contrast signals from the basis for then computing higher-order visual features, one of which is motion information. At the end of my talk, I will show how motion computation is tuned to the behavior of the animal already in local direction-selective cells, which encode patterns of optic flow at the population level. Together, our work argues that visual processing strategies have evolved to handle the demands imposed by the animal’s own behavior.

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