ESTABLISHMENT AND APPLICATION OF WORKFLOWS FOR STRUCTURE-FUNCTION ANALYSIS OF SYNAPTIC COMPONENTS

At the site of neuronal communication, multiple interacting components drive synapse structure and function. Synaptic vesicle pools, membrane proteins, mitochondria, and perisynaptic astrocyte processes (PAPs) are all structures that can be altered through naturally occurring plasticity mechanisms to modulate neurotransmission, and disruption of these structures can result in synapse dysfunction and disease. Due to the minute size of the synapse, electron microscopy (EM) remains the gold standard for ultrastructural characterization; however, due to the complexity of EM datasets, extraction of information has become a bottleneck which places limits on the amount of data that can be collected and analyzed. A need exists for easy-to-use workflows that automate and enhance analysis throughput, to keep up with the streams of image data that are able to be produced. Here, I develop the use of AI algorithms, correlative microscopy techniques, and novel structural analysis methods to characterize postsynaptic mitochondria, PAPs, synaptic vesicles, and integral membrane proteins and their impact on synapse structure and function. I show that both postsynaptic mitochondria and PAPs in the visual cortex are positioned to support synapse structure and function; cleavage of a synaptic adhesion molecule affects synaptic vesicle accumulation in the amygdala; and presynaptic voltage gated calcium channels aggregate near active zone machinery in the brainstem. In addition, I highlight the use of virtual reality as a fast and intuitive tool for the identification and isolation of individual neurites in 3D EM. Thus, my work establishes novel technical approaches for EM and advances our understanding of neuronal communication through original research of several synaptic components.