Title: The spatial distribution of cortical interneurons
Description: The spatial patterning of neurons is a fundamental problem in neuroscience. The functions of the brain are rooted in the cellular architecture that underlies the structure of the brain. In the cerebral cortex, the functions of the cortex depend on the proper assembly of circuits made up of long-range excitatory neurons and locally-projecting inhibitory interneurons. Interneurons are incredibly diverse from a morphological and functional perspective and are found in every cortical area. Unlike excitatory cortical neurons, interneurons are born outside of the cortex and migrate long distances into the cortex and distribute across the cortex broadly. How do these diverse cells that essentially invade the cortex properly distribute? How do different developmental stages contribute to the final patterning of interneuron subtypes, and what are the molecules that influence this process? In this dissertation, I will present my original research which has advanced our knowledge of the answers to these fundamental questions in the field of developmental neuroscience.

I addressed these questions by applying a range of techniques including mouse genetics, immunohistochemistry, confocal microscopy, and point pattern analysis. My research has shown that cortical interneuron subtypes are spatially independent. Spatial patterns of cortical interneuron subtypes are non-random within subtypes, but are randomly positioned with respect to other subtypes. I also explored the effects of loss of diversity within the clustered protocadherin family of adhesion molecules. Though these molecules do not appear to play a role in subtype specific spatial independence, I found that loss of clustered protocadherin diversity alters the density and laminar distribution of cortical interneuron subtypes. I also contributed to the development of genetic tools which could help us further understand how developmental stages contribute to final interneuron distribution. My original research has collectively advanced our knowledge of how cortical interneurons achieve their final distributions during development and has opened up new avenues of scientific inquiry for future research in developmental neuroscience.