Several studies have reported that the paraventricular nucleus of the thalamus (PVT) is a sensory relay node in the brain that interacts with fear circuitry. However, little is known about the PVT in relation to safety learning, particularly its interaction with the central nucleus of the amygdala (CeA) in the context of safety expression. Here, 32 Long-Evans male and female rats receive a surgically placed retrograde tracer into the CeA, which assesses neural connectivity from PVT to CeA. Safety training is first initiated, followed by habituation, and then the rats are exposed to either foot shocks or safety condition stimuli (CS). Behavioral freezing is assessed, followed by the collection of brains for subsequent immunohistochemical analysis of cellular activity, focusing specifically on cells projecting from the PVT to CeA. We expect to see increased freezing in the context of threat alone as compared to the threat plus safety. We also anticipate females to exhibit slightly higher freezing responses than males. Furthermore, we predict an increase in c-Fos activity among CeA-projecting PVT cells in the context of threat plus stimulus as compared to the threat plus safety, with females showing slightly higher c-Fos activity than males. This project contributes to a deeper understanding of the neurobiological factors that concern the expression of safety learning by highlighting the brain regions involved in this process. This provides valuable insights into the fields of neuroscience and psychology from exploring the mechanisms through which individuals develop fears or acquire a sense of safety, enhancing our understanding of the underlying causes of anxiety-related disorders. Through behavioral testing both males and females demonstrated safety learning, immunohistochemistry (IHC) has been completed, and microscopy and image analysis is currently underway.
Authors: Noelle E. Naccarato, McKenzie B. Pham, Grace L.E. Rempel, Jordan S. Roth, August O. Ogunnowo, Quinn, J.J.
Advisors: Jennifer J. Quinn, Psychology
Amanda N. Reichert, Psychology
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