Watching the brain in action can help advance our knowledge of how neuronal activity produces behaviors but currently, long-term brain monitoring systems have a limited field of view. Here, the multidisciplinary collaborative group will create a novel head-mounted miniscope that will image large areas of the cortex in freely moving mice. Based on their novel computational imaging framework, the researchers aim to develop the Computational Miniature Mesoscope (CM2), which uses parallel sampling with single lightweight microlens array to simplify the optical path, producing an increased field of view with maximized light-throughput, resolution and signal-to-noise ratio. The team will develop novel optical designs for ‘wearable’ cellular-resolution Ca2+ imaging throughout neocortex and then validate and optimize the CM2 for cortex-wide functional imaging in behaving mice. This new technology aims to expand researchers’ ability to probe neuronal activity over large areas of the brain, furthering our understanding of the neural basis of behavior.