Circuit mechanisms of computation with X-ray connectomics

Understanding mammalian brain function requires linking neuronal activity directly to structural connectivity at large scales (mm³ to cm³). This project addresses this challenge by developing and applying advanced X-ray connectomics methods to reveal how neural circuits transform sensory information. Using the mouse olfactory system as a model, we combine in vivo functional imaging with X-ray holographic nanotomography (XNH). Our interdisciplinary approach merges expertise in systems neuroscience and synchrotron-based X-ray physics to achieve unprecedented resolution (~20 nm) and sample volumes (several mm³, ultimately whole mouse brains).In Aim 1, we will significantly enhance XNH technology by optimizing imaging protocols, reconstruction algorithms (including multislice tomography and non-rigid reconstruction), sample staining, and segmentation tools, validated by high- resolution electron microscopy and paving the way for whole mouse brain X-ray connectomics. In Aim 2, we will dissect olfactory bulb transformations by correlating activity patterns of input (glomeruli) and output neurons (mitral/tufted cells) with their underlying anatomical circuits. This approach will enable direct investigation of the logic behind circuit computations, such as long-range inhibition. Our work leverages recent upgrades at the European Synchrotron Radiation Facility (ESRF) and positions X-ray connectomics as a transformative method for neuroscience, providing a scalable platform to decode brain-wide connectivity and computation.