We are constantly inundated with a barrage of sensory information. At any given instant, however, only a small key fraction of this sensory world is relevant for taking action. Our brains must select out the critical input and use it to guide behavioral response. We often call this selection process attention.A field mouse, for example, scurrying through the grass scanning for delicious morsels attends to the ground below. The moment, however, the shadow of a hawk flashes by the mouse freezes in an instant attention was shifted from below to the imminent danger in the sky above. Attention is central to sensory processing and critical to survival. It is dynamically moved around to select the key sensory input. These changes in information selection occur extremely rapidly in the brain. This proposal aims to understand the cellular mechanisms driving this selection process. I develop a interdisciplinary approach using a novel spatial attention task in mice, and leverage this genetically tractable animal model, state-of-the art in vivo sub-cellular 2-photon imaging, optogenetics, & patch-clamp recordings to dissect the microcircuits & synaptic mechanisms that mediate these rapid changes in sensory processing.I will be hosted by Dr. Mainen at Portugal’s newly established Champalimaud Neuroscience Program. The systems neuroscience focus of the CNP, my past research experience, scientific interest & career goals makes this proposal the perfect match for both the host and I. This project will not only provide data on fundamental open questions regarding sensation & cognition, it will also allow me to develop a multidisciplinary approach to systems neuroscience. Combining sophisticated behavioral assays with next-gen techniques in optogenetics & imaging, this project puts the host lab and I at the bleeding-edge of systems neuroscience research. By funding this study, the Marie Curie Work Programme will secure its long-held leading role in supporting innovative research.