Association of Increased Amygdala Activity with Stress-Induced Anxiety but not Social Avoidance Behavior in Mice

 Shou-He Huang1 • Wei-Zhu Liu1 • Xia Qin1 • Chen-Yi Guo1 • Qing-Cheng Xiong1 • Yu Wang1 • Ping Hu2 • Bing-Xing Pan1 • Wen-Hua Zhang
1 Laboratory of Fear and Anxiety Disorders, Institutes of Life Science, Nanchang University, Nanchang 330031, China 
2 Institute of Translational Medicine, Nanchang University, Nanchang 330001, China
Chronic stress leads to many psychiatric disorders, including social and anxiety disorders that are associated with over-activation of neurons in the basolateral amygdala (BLA). However, not all individuals develop psychiatric diseases, many showing considerable resilience against stress exposure. Whether BLA neuronal activity is involved in regulating an individual’s vulnerability to stress remains elusive. In this study, using a mouse model of chronic social defeat stress (CSDS), we divided the mice into susceptible and resilient subgroups based on their social interaction behavior. Using in vivo fiber photometry and in vitro patch-clamp recording, we showed that CSDS persistently (after 20 days of recovery from stress) increased BLA neuronal activity in all the mice regardless of their susceptible or resilient nature, although impaired social interaction behavior was only observed in susceptible mice. Increased anxiety-like behavior, on the other hand, was evident in both groups. Notably, the CSDSinduced increase of BLA neuronal activity correlated well with the heightened anxiety-like but not the social avoidance behavior in mice. These findings provide new insight to our understanding of the role of neuronal activity in the amygdala in mediating stress-related psychiatric disorders.
Chronic stress; Amygdala; Stress vulnerability; Anxiety; Fiber photometry; Neuronal activity