The amygdalae are groups of nuclei in the temporal lobes of our brain which play a crucial role in processing decisions and emotions and consolidating memories. It is well known that the left and right hemispheres of the brain control different cognitive and motor functions, and likewise, amygdalae perform different tasks depending on the hemisphere where they reside. Studies have shown that the right amygdalae produce negative emotions such as fear and sadness, whereas the left amygdala not only produce those, but also positive feelings.
Amygdala and Social Anxiety
The consolidation of memories is a complex process: an event will first be stored as a short-term memory before it is slowly assimilated to potentially form a long-term, and possibly life-long memory. If emotional arousal occurs following the event, memory retention will be higher. The amygdalae, especially the basolateral nuclei, also mitigate the impact that emotional arousal has on the strength of the memory.
Given the essential role that the amygdalae clearly play in regulating emotions and retention of past experiences, it is no surprise that physical damage to the temporal lobes would result in social and emotional difficulties. In the late 19th century, experiments in primates showed that when the amydgalae were damaged, rhesus monkeys would display hypo-emotionality, i.e. a reduced ability to feel emotions, loss of fear, and an inability to distinguish animate from inanimate objects. Furthermore, female monkeys showed less maternal behaviours towards their progeny, even sometimes neglecting and abusing their babies.
More recently, research using Magnetic Resonance Imagery (MRI) technology has shown that children with anxiety disorders tended to have a smaller left amygdala, and indeed, various studies has demonstrated that the amygdala is at the heart of mental states and is connected to many psychological disorders such as social anxiety disorder, OCD (Obsessive Compulsive Disorder), PTSD (Post-Traumatic Stress Disorder), BPD (Borderline Personality Disorder) and general anxiety.
The amygdala is also known to be the “fear centre” of the brain, and experiments measuring the activity of the left amygdalae in response to a fear stimulus also highlighted its fundamental role. When presented with images of threatening faces or placed in frightening situations, patients suffering from depression or social phobia were observed to have an exaggerated level of activity in the left amygdala. Interestingly, this hyperactivity decreased with the use of anti-depressants.
What does the amygdala control?
The link between the amygdala and fear processing sheds a light on how anxiety can take root in a person’s mind and develop into long-term problems.
This connection served us well when we were cavemen facing life-threatening dangers: let’s say you encountered a tiger and they greeted you with a threatening growl and bared their teeth. Your amygdala would spring into action and trigger a fear response –rather than encourage you to go and stroke the big kitty!
You would either fight or flee, but in addition, as this experience was accompanied by strong emotions, it would be processed into a life-long memory. Next time you would leave your cave, you would know that all tigers, not only the one you met, are dangerous, and, very wisely, you would avoid them.
This was very useful, but in modern life, it can cause us more trouble than not.
Fast-forward a few millennia. A timid child is unfortunate to experience unsuccessful attempts at making friends and socialising. The unhappy feelings this will inevitably produce, coupled with the memory processing of the amygdala, will sadly, start a vicious circle of generalisation and avoidance behaviour which will associate people with distressing emotions, and stimulate anxiety, which will in turn, reduce the ability of that person to interact with people and interpret their behaviours positively.
Amygdala and Anxiety Treatment
While antidepressants have been shown to regulate the response of the amygdala and can help in controlling anxiety, it is interesting to note that compassion meditation and mindfulness practice in Buddhist monks has also been observed to regulate the amygdala in a similar way, and that it was stronger in experienced monks than in novices. So, meditation is not only for New Age hippies, it does have a real impact on anxiety and reduces your fear response to situations and people. It is, without a doubt, a very effective tool to reverse an imbalanced neurological process.
Mindfulness-based therapies, which have their origins in Buddhist philosophy, have been used for decades to treat social anxiety disorders and are now widely recognised as one of the most efficient form of talking therapies for social phobia. They use a range of techniques based on being in the present moment, observing your feelings while detaching yourself from them, and meditation.
Had any of you heard about the amygdala before? What else do you know about this part of the limbic system? I’d love to hear from you.
All the best, Kyle