Kaitlin Sullivan

Following a traumatic event, many individuals will experience adverse psychological symptoms which diminish over time. For some, however, these symptoms will persist, resulting in post-traumatic stress disorder (PTSD). This anxiety disorder imposes a significant burden on individuals and society. As such, it is important to better understand the neural mechanisms underlying PTSD so that effective mitigation strategies can be developed. Our research has shown that the classic neuronal types of many brain regions – like those brain regions involved in fear memory – can be divided into distinct subtypes of neurons based on the genes they express.

This difference in gene expression often translates to differences in function and connectivity. My project seeks to identify the unique subtypes of neurons participating in the creation and retrieval of fear memories. Using a new, cutting-edge histology technique, I am fluorescently tagging important “marker genes” – genes uniquely expressed in a certain subtype. This will resolve the spatial organization of subtypes in fear memory associated brain regions. This will be followed by fear conditioning on transgenic mice, wherein we can fluorescently tag neurons active during memory formation and memory retrieval.

This fluorescent tagging of active neurons, in conjunction with the subtype map, will identify the subtypes of neurons that participate in the creation and recollection of fear memory. The data from this project will establish which subtypes of neurons are key in the formation and retrieval of fear memory. This both investigates a basic question of neuroscience and further elucidates cellular and molecular targets causally related to fear memory – providing a vital framework for future work developing therapeutic interventions for PTSD. In the near future, our laboratory will extend aspects this work in human tissue, with the hopes that the long-term results of our work will eventually assist in aiding those suffering from PTSD.