Cortical visual processing for navigation

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Project summary Vision plays a key role in our ability to navigate through the environment, from identifying landmarks and obstacles to determining location and heading. While studies of visual cortex have provided an understanding of properties such as orientation selectivity and object recognition, much less is known about how cortical circuitry extracts and processes features from the visual scene to support navigation. In particular, there are two challenges. First, the nature of the visual stimulus is dramatically different in navigation, where the subject's movement through the world creates a complex and dynamic visual input, in contrast to standard synthetic stimuli presented to stationary subjects. Second, the types of visual features and computations that must be performed are different in navigation than in standard detection or discrimination paradigms. Our goal in this proposal is to determine how the brain extracts relevant visual features from the rich, dynamic visual input that typifies active exploration, and investigate how the neural representation of these features can support visual navigation. We will investigate this through three parallel aims, that build up from the representation of the visual scene in V1 during freely moving navigation, to the computation of specific variables needed for navigation. In our first aim, we will measure the visual input in freely moving mice using miniature head-mounted cameras, together with neural activity in V1, to determine how neural dynamics represent the visual scene during natural navigation. In our second aim, we will use large field-of-view two-photon imaging of multiple cortical areas, while mice navigate in a naturalistic open-world virtual reality system, to determine how visual features are represented across visual cortical areas. In our third aim, we will use 2-photon imaging in mice in a rotational arena to determine how visual input is used to dynamically update a key navigational variable: heading direction. Together, this project bridges foundational measurements in freely moving animals with mechanistic circuit investigations, to provide insights into an important aspect of visual system function.