The Physiology of Fear: Reconceptualizing the Role of the Central Amygdala in Fear Learning.
The historically understood role of the central amygdala (CeA) in fear learning is to serve as a passive output station for processing and plasticity that occurs elsewhere in the brain. However, recent research has suggested that the CeA may play a more dynamic role in fear learning. In particular, there is growing evidence that the CeA is a site of plasticity and memory formation, and that its activity is subject to tight regulation. The following review examines the evidence for these three main roles of the CeA as they relate to fear learning. The classical role of the CeA as a routing station to fear effector brain structures like the periaqueductal gray, the lateral hypothalamus, and paraventricular nucleus of the hypothalamus will be briefly reviewed, but specific emphasis is placed on recent literature suggesting that the CeA 1) has an important role in the plasticity underlying fear learning, 2) is involved in regulation of other amygdala subnuclei, and 3) is itself regulated by intra- and extra-amygdalar input. Finally, we discuss the parallels of human and mouse CeA involvement in fear disorders and fear conditioning, respectively.
Department of Psychiatry and Behavioural Sciences, Emory University School of Medicine, Atlanta, Georgia; Yerkes National Primate Research Center, Atlanta, Georgia.
Orion P
OP
Keifer
Department of Psychiatry and Behavioural Sciences, Emory University School of Medicine, Atlanta, Georgia; Yerkes National Primate Research Center, Atlanta, Georgia.
Robert C
RC
Hurt
Department of Psychiatry and Behavioural Sciences, Emory University School of Medicine, Atlanta, Georgia; Howard Hughes Medical Institute, Bethesda, Maryland; and Yerkes National Primate Research Center, Atlanta, Georgia.
Kerry J
KJ
Ressler
Department of Pharmacology and Physiology, George Washington University, Washington, D.C.; pmarvar@gwu.edu.
Paul J
PJ
Marvar
D000818:Animals; D001245:Association Learning; D001522:Behavior, Animal; D066274:Central Amygdaloid Nucleus / Q000378:metabolism / Q000502:physiology*; D003213:Conditioning, Psychological; D005239:Fear; D006801:Humans; D008568:Memory; D009434:Neural Pathways / Q000502:physiology; D009473:Neuronal Plasticity; D009479:Neuropeptides / Q000378:metabolism
D009479:Neuropeptides