Axially decoupled photo-stimulation and two photon readout (ADePT) for mapping functional connectivity of neural circuits
All-optical in vivo physiology enables three-dimensional interrogation of neural circuits function. Here, we introduce ADePT (Axially-Decoupled Photo-stimulation and Two-photon readout), a strategy that combines flexible optogenetic stimulation with neural activity imaging. ADePT achieves axially contained widefield patterned stimulation by coupling a digital micro-mirror device illuminated by a solid-state laser to a motorized holographic diffuser, while in parallel performing multiphoton imaging across different z-planes. As a proof of principle, we apply ADePT to map excitatory and inhibitory functional connectivity in the mouse early olfactory system. By controlling activity in individual glomeruli on the olfactory bulb surface and recording responses from output mitral and tufted cells in deeper layers, we identify cohorts of sister cells driven by the same parent glomerulus and analyze their distinct connectivity patterns. We further report specificity in the inhibitory circuitry, as we find that GABAergic/dopaminergic (DAT+) interneurons associated with different glomeruli selectively suppress baseline and odor-evoked activity in distinct mitral and tufted cell populations. Together, these results establish ADePT as a platform for high-throughput functional connectivity mapping in optically accessible brain regions.