Sarah Thai
Mary Gates Research Scholar
Winter 2023
Project
Modulation of Anxiety-Like Behavior by Norepinephrine Signaling in the Basolateral Amygdala
This study aims to elucidate stress-induced anxiety-like behaviors, with a specific focus on the noradrenergic signaling in the basolateral amygdala (BLA). Anxiety disorders represent a significant global health burden, affecting 30% of the population at some point in their lives. Unfortunately, the neurobiological mechanisms driving anxiety-like behaviors, particularly those induced by stress, remain incompletely understood. Past research indicates the limbic system, a group of interconnected brain regions, play a pivotal role in processing emotions and behaviors. Among these regions, the BLA is crucial for the expression of anxiety-like responses, receiving noradrenergic input from the locus coeruleus (LC). Although the LC’s involvement in promoting aversion and increasing anxiety-like behavior has been established, specific neuronal cell types and receptors responsible for these effects remain unidentified. Therefore in hopes of identifying these specific neuronal cell types and receptors, I will use CRISPR/SaCas9 gene editing technology to selectively knock down β adrenergic receptors in BLA neurons to prevent these receptors from responding to noradrenaline (NE) release in response to stress. Specifically, adrenergic receptors alpha-1 (Adra1a) and beta-2 (Adrb2) will be targeted in either glutamatergic or GABAergic BLA neurons to determine their distinct contributions to stress-induced anxiety-like behavior. I will then expose mice to a synthetic predator odor (trimethylthiazole) to elevate the tonic activity of LC-NE neurons and subsequently assess anxiety-like behavior using a series of well-established designs: Novelty-Suppressed Feeding (NSF), Open Field Test (OFT), and Elevated Zero Maze (EZM). To obtain unbiased behavioral data, a machine learning model based on Deep Lab Cut pose estimation and Simple Behavioral Analysis (SimBA) will be employed. The significance of this study lies in its potential to uncover precise cellular and receptor mechanisms that mediate anxiety and aversion induced by stress-induced tonic LC activation with the hopes of aiding in the development of more efficacious drugs for treating anxiety disorders.