MOLCONN · Molecularly informed dense connectomic mapping of mammalian brain tissue

Complex wiring between neurons underlies the information processing network enabling all brain function. Fundamental questions on how the network is organized, how structural connectivity relates to the cells’ molecular machineries and how cells, synaptic connections, and circuits evolve over time remain enigmatic. Addressing these questions is beyond the limits of current measurement technologies, as these either lack resolving power to untangle cellular connectivity or can’t visualize the molecular characteristics of cells, such that these functionally highly interlinked modalities of information remain disconnected in current analysis.Here, we will devise transformative optical imaging technologies for multi-molecular mapping in relation to dense, synaptic resolution connectomic reconstruction of the same cells. We will directly integrate multiplex protein information and in-situ gene expression profiling with connectomic reconstruction. This will reveal cell types and states and the molecular machineries involved in intercellular signaling mapped, onto neuronal morphology and synaptic connectivity patterns. The technology will be based on high-fidelity expansion microscopy with combined structural and multi-molecular readout. We will apply MOLCONN to study the functional architecture of brain tissue across development and ageing in healthy mice with unprecedented information content. We will then define multi-modal organizational rules in human brain tissue. Analysis of the ageing brain will serve as reference frame to bridge from genotype/disease states to tissue-level functional phenotypes in neurodegenerative disease in a mouse model of Parkinson’s disease.We will use a uniquely cross-disciplinary approach integrating developments in imaging, sample preparation, molecular labeling, and computational data interpretation to build unified models of molecular and structural circuit properties to address the fundamental question of how these interrelate.