Neural circuits composed of interconnected neurons with distinct properties lay the physical foundation of any brain function. Identifying connections between individual neurons is central to understand how information is processed and propagated in the brain. While emerging high throughput light microscopy technologies are highly promising in allowing whole brain scale imaging at the single cell level, optical resolution limitation prevents their use in differentiating densely labeled neuronal processes in the same brain. In addition, computational tools for automatically extracting morphological information from intermingled neurons with high accuracy are still lacking. Our team will concurrently develop novel genetic tools for neuronal labeling, super-resolution imaging, and automated neuronal tracing for high-throughput circuit reconstruction. We will apply these tools to obtain densely reconstructed inhibitory microcircuits in the mouse cortex. These tools will be readily applicable for studying other long-standing questions in neuroscience and the resources generated by this project will be useful for future computational tool development.
Neuronal morphology is an important attribute for characterizing neural developmental and degenerative diseases. Abnormal dendritic and/or axonal arbors indicate disfunction in neuronal activity and connectivity. Automated reconstruction of neural circuit from a densely labeled brain remains a technical challenge as the intermingled neuronal processes result in many ambiguities when they appear as running into each other in a light microscopy image. We will develop an integrative strategy, which combines advanced labeling, sample preparing, imaging and computing techniques to permit automated microconnectivity analysis in regular neurobiology labs. Our study on inhibitory microcircuits in the mouse cortex will greatly advance the fundamental knowledge about how inhibition is formed. This is highly relevant to the circuitry mechanism of Autism Spectrum Disorder and many other neural disorder diseases, which are caused by an excitation-inhibition imbalance in the brain.