The Amygdala
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Written by: Deepika Miryala
Edited by: Aylin Abbasi and Nadia Hall
Introduction
Research on the amygdala has uncovered its numerous purposes and complex properties. Its ties to emotions and fear responses have been the primary subject of these studies, but the amygdala plays a role in many different functions and coordinates with several different brain regions. Experiments have been conducted with both humans and mice to test such functions, and the findings have greatly advanced our understanding of the amygdala’s structure and paved the way for future studies. Some of the neurological domains that are associated with the amygdala include emotions, memory, and learning. Additionally, when the amygdala faces harm, there are a plethora of consequences, including neurological disorders and mental health conditions. Many harmful causes and symptoms have been identified as being related to amygdala impairment, and various conditions are associated with it. All in all, there are many remarkable facts to be noted about the amygdala that provide further insights into this incredible part of the brain.
Location and Structure of the Amygdala
The amygdala is a part of the brain that is involved in the limbic system, a brain network primarily associated with emotions (AbuHasan et al., 2023). Structurally, the amygdala consists of a small pair of almond-shaped parts located in the temporal lobe, near the hippocampus (Rowden, 2021). To paraphrase an article from the the Cleveland Clinic, the amygdala is primarily made up of neurons and glial cells:
Neurons are the most specialized cells of the nervous system, responsible for transmitting chemical and electrical signals throughout the brain and body. These neurons bundle together to create nuclei, and the amygdala contains 13 such nuclei.
Glial cells, on the other hand, are the neurons’ designated support cells. There are many different types of glial cells in the nervous system. Examples include astrocytes, which help maintain the blood-brain barrier, and oligodendrocytes, which are responsible for building myelin sheaths (Cleveland Clinic Medical [CCM], 2025).
Functions of the Amygdala
As explained by a 2023 article from the National Library of Medicine titled “Neuroanatomy, Amygdala”, the amygdala, while small in size, is responsible for a variety of essential physiological functions. One of its most fundamental roles is emotional processing, particularly in relation to fear. More specifically, it is associated with fear conditioning/mediation, meaning it uses past experiences to produce the appropriate behavioral and physiological responses to a fear-inducing stimulus (AbuHassan et al., 2023).
Experiments have shown that electrical stimulation of the human amygdala can elicit fear responses, demonstrating its central role in fear processing. Through fear conditioning, the amygdala allows individuals to learn from past experiences and avoid harmful situations (e.g., automatically withdrawing one’s hand from a hot stove). Aside from just programming for adverse scenarios, the amygdala also conditions us to desire rewarding stimuli such as food, sex, and drugs.
In addition to its role in emotional conditioning, the amygdala contributes to emotional regulation and is linked to anxiety, aggression, and the formation of emotional memories (Dingman, n.d.). To go into more detail, the amygdala triggers a “fight-or-flight” response when it senses a frightening stimulus. This can speed up breathing and heart rate as the body decides whether to confront the stimulus or try to avoid it. By enabling fast, automatic reactions, the amygdala allows us to respond reflexively without deep thinking, such as jumping back when seeing a snake. Moreover, it stores fear-producing events by creating emotionally charged memories about them. For example, if a mouse is exposed to an electric shock after a certain sound is played, the mouse will begin associating that sound with the painful shock and start displaying a fear reaction every time it hears it, demonstrating that the mouse has formed negative memories of the painful experience (Dingman, n.d.).
Some of the higher cognitive functions the amygdala contributes to include learning and making decisions (Denslow, 2022). In terms of learning, the amygdala contributes to interpreting rewards and punishments, and therefore plays a role in adjusting behavior. A simple example of this process is training a dog to sit using treats as reinforcement. Overall, the amygdala is involved many different functions, making it a versatile and vital part of the brain.
Amygdala Damage and Dysfunction
Like any other brain structure, damage to the amygdala can have serious consequences. Traumatic brain injury, stroke, seizure, temporal lobe epilepsy, and Alzheimer’s disease are all common causes of amygdala impairment (Denslow, 2022). Regarding Alzheimer’s specifically, it has been posited that the memory loss that characterizes this condition is a result of neuronal degeneration in the amygdala (Dingman, n.d.). Potential signs of amygdala damage include anxiety disorders, such as post-traumatic stress disorder, obsessive-compulsive disorder, and frequent panic attacks (Wendt, 2024). Additionally, memory problems can be a result of amygdala dysfunction, because memory loss occurs when the amygdala and hippocampus (another brain structure associated with emotion and memory) do not function together properly (Dingman, n.d.). Amygdala damage is also associated with hypervigilance (a state of heightened alertness) and difficulties in decision-making (Denslow, 2022).
One lesser known neurological disorder related with amygdala damage is Kluver-Bucy Syndrome, which involves symptoms like hyperorality (affinity for oral sensations), placidity (a state of calmness), and insatiable appetite (Dingman, n.d.). Aside from that, conditions such as brain cancer and Autism Spectrum Disorder have also been shown to be associated with impairment of the amygdala (Cleveland Clinic Medical [C. C. M.], 2025). The wide range of health conditions impacted by amygdala dysfunction goes to show how integral it is to the brain, and the variety of functions it aids in.
Lastly, a potentially harmful phenomenon known as amygdala hijack describes the situation in which the amygdala causes a person to overreact to a stimulus. During an amygdala hijack, individuals struggle to think clearly about what is happening and typically respond in a way that is out of proportion (Rowden, 2021). The name represents how an overwhelmed amygdala literally “hijacks” the rational parts of the brain, releasing cortisol and adrenaline (stress hormones) to promote the body’s “fight-or-flight” response (Denslow, 2022). To prevent this from happening, taking a deep breath and evaluating one’s stressors can reduce the risk of amygdala hijack (Rowden, 2021).
Conclusion
At first glance, the amygdala may not seem all too significant. However, as its functions have been identified, it has become apparent that this small part of the brain actually plays a major role in everyday cognitive functions, particularly those related to memory and emotion. As neuroscience and neurological medicine advance, a deeper understanding of the amygdala’s structure and functions becomes crucial to answering some of the most enduring questions of neurological research.
References
AbuHasan, Q., Reddy, V., & Siddiqui, W. (2023, July 17). Neuroanatomy, amygdala. StatPearls - NCBI Bookshelf. https://www.ncbi.nlm.nih.gov/books/NBK537102/
Cleveland Clinic Medical [C. C. M.]. (2025, September 30). Amygdala. Cleveland Clinic. https://my.clevelandclinic.org/health/body/24894-amygdala
Denslow, E. D. (2022, November 9). Damage to the amygdala: Understanding the functions, symptoms, & treatments. Flint Rehab. https://www.flintrehab.com/damage-to-the-amygdala/
Dingman, M. (n.d.). Know your brain: Amygdala. Neuroscientifically Challenged. https://neuroscientificallychallenged.com/posts/know-your-brain-amygdala
Rosenfeld, J. (2017, March 2). 7 Amazing Facts about the Amygdala. Mental Floss. https://www.mentalfloss.com/article/92395/7-amazing-facts-about-amygdala
Rowden, A. (2021, April 19). What to know about amygdala hijack. https://www.medicalnewstoday.com/articles/amygdala-hijack
Wendt, T. (2024, November 19). Amygdala: What to know. WebMD. https://www.webmd.com/brain/amygdala-what-to-know