Amygdala

An important distinction is amygdala is a subcortical structure involved in mobilization of defense behavior in response to immediate threats and is not the source of conscious experience of anxiety or fear (LeDoux 2017).

• Lateral amygdala processes incoming sensory stimuli, has capacity to learn (via conditioning) to associate certain stimuli with threat (Johansen et al, 2011).
• Central amygdala processes information from lateral amygdala and may lead to freezing pathways or to basal amygdala and more goal oriented avoidance behaviors (LeDoux and Pine, 2016)
• More chronic / distant / uncertain threats are processed by the bed nucleus of the stria terminalis (Daniel and Rainnie, 2016; LeDoux and Pine 2016; Yassa et al, 2012)

References

Daniel, S. E. & Rainnie, D. G. Stress Modulation of Opposing Circuits in the Bed Nucleus of the Stria Terminalis. Neuropsychopharmacology 41, 103–125 (2016). https://pubmed.ncbi.nlm.nih.gov/26096838/

LeDoux, J. E. & Pine, D. S. Using Neuroscience to Help Understand Fear and Anxiety: A Two-System Framework. Am. J. Psychiatry 173, 1083–1093 (2016). https://pubmed.ncbi.nlm.nih.gov/27609244/

LeDoux, J. E. Semantics, Surplus Meaning, and the Science of Fear. Trends Cogn. Sci. 21, 303–306 (2017). https://pubmed.ncbi.nlm.nih.gov/28318937/

Johansen, J. P., Cain, C. K., Ostroff, L. E. & LeDoux, J. E. Molecular Mechanisms of Fear Learning and Memory. Cell 147, 509–524 (2011). https://pubmed.ncbi.nlm.nih.gov/22036561/

Yassa, M. A., Hazlett, R. L., Stark, C. E. L. & Hoehn-Saric, R. Functional MRI of the amygdala and bed nucleus of the stria terminalis during conditions of uncertainty in generalized anxiety disorder. J. Psychiatr. Res. 46, 1045–1052 (2012). https://pubmed.ncbi.nlm.nih.gov/22575329/