Experience-Dependent Plasticity in Superior Colliculus and Natural Visual Behavior

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PROJECT SUMMARY/ABSTRACT Our long term goal is to identify and understand the mechanisms underlying plasticity in visual stimulus detection and visually-guided pursuit. Plasticity in these visuospatial orienting behaviors are perturbed in both neurodevelopmental disorders such as autism as well as neurological disorders resulting from traumatic experiences such as PTSD. Thus, development and plasticity of these visual orienting behaviors critically impact healthy visual processing. In order to ultimately develop targeted therapies that alleviate the specific visual processing deficits associated with each disorder, it is necessary to first understand the mechanisms that underlie the development and plasticity of visual stimulus detection and pursuit behaviors more fundamentally. We will start to address this critical gap by investigating the development and sensory experience-dependent plasticity of function of specific cell types of the superior colliculus in the mouse as they relate to specific changes in visual stimulus detection and pursuit behavior. The superior colliculus is a key subcortical visual system that processes salient environmental stimuli, receives substantial input from cortex and mediates rapid spatial orienting behavior in all mammals. The function of cells in this structure are sensitive to visual experience and change significantly over development, and, two classes of cells in the superior colliculus known as the wide- and narrow-field vertical neurons specifically underlie visual stimulus detection and pursuit. However, we do not understand how these precise neural circuits are directly impacted by visual experience throughout life. The mouse affords access to a broad range of sophisticatedgenetic tools that may be used to close this gap in our understanding. In AIM 1, we will quantify stimulus detection and pursuit behaviors at key developmental stages from postnatal day 21 to adulthood to understand how these visual orienting behaviors change in the mouse. In AIM 2, we will determine whether specific circuit changes support developmental changes in behavior by quantifying the neural encoding of visual stimuli specifically in the wide- and narrow-field cell circuits of the superior colliculus in the behaving animal. We will measure specific neural activity using high- density in vivo electrophysiology, optogenetics, virus mediated circuit tracing, calcium imaging and functional ultrasound imaging. In AIM 3, we will study the experience-dependent development of both behavior and specific circuit function in the superior colliculus by manipulating visual experience by allowing mice to hunt live insects (enrichment). Overall, this work will advance our understanding of the neural circuit mechanisms underlying successful spatial orienting behaviors that are essential for visual perception.