Blessed Amygdala!

Dr. Alexander Perski, an expert in stress, and a guest at Villa San Michele, writes of his experiences during a walk around the area. He also writes about the amygdala, a structure in the reptile brain, which helps us in dangerous situations.

To get started writing on Anacapri I began the day with a walk along the path that leads to the hermitage of Cetrella on the other side of the mountain. Just before I reached the point where I had a view over the entire island, I found myself suddenly standing about three meters from the path in the middle of a rosemary bush. After a moment of confusion I recalled a rather large black snake slithering from a sunny stone right in front of my feet.

Perski writes:

In the middle brain, just behind my eyes, I have just like everyone else, thank goodness, a little structure called the amygdala that has the ability to distance me from danger without conscious involvement.

This almond-shaped structure (amygdala means almond in Latin) is thought to function as a centre for emotional reactions, primarily in questions of threats, fear, or terror.

Perski writes:

The Amygdala continually receives information from our senses about everything that happens around us. It is obvious that this little structure instantly processes incoming data and can discern images, sounds, smells or tastes previously associated with something very dangerous.

There probably is a continuous accumulation of emotional memories in the amygdala. Most of what we experience in life leaves traces there, especially experiences of things that are frightening. The quickness with which this structure can process emotionally negative information that indicates danger, and the emotional memories that it holds, has certainly been of great advantage to us, despite the occasional false alarm.

In the ages when human life was not especially varied and the different dangers we faces were not so dissimilar, this system was certainly extremely effective.

Modern life, with its constant changes and new situations and environments not previously experienced, can overload the amygdala and lead us astray.

The Seahorse in the Brain

The Amygdala is aided by a nearby structure in the brain called the hippocampus (seahorse). In the hippocampus there is an orientation in time and space and a summary of information in the form of a complete modelling of impressions, feelings, and facts concerning important events. It is probably in this form that data is later archived in the cerebral cortex, and it also seems that the amygdala uses this information to choose between action and non-action when there is a sudden danger signal.

The Amygdala has at its disposal a powerful system to save us from danger. In my case it succeeded in moving 80 kilograms of body weight to a comfortable distance from the grass snake, but not so far that I fell off the nearby cliff edge, thanks to the hippocampus, which is also equipped with a very effective GPS system.

On my next visit, when I was updating my book about stress ”Ur balans”, the gardener of San Michele told me that the grass snakes of Capri are not poisonous. With this knowledge I resumed my walks up the mountain. Once I saw a large black snake resting in the sun on a wall I wanted to pass.

Perski writes:

At this point there was a struggle between the amygdala (my middle brain) and my cerebral cortex – the snake is dangerous – no it isn’t, I’m just going to walk past slowly. I took hold of myself and went by almost running.

But afterwards I was completely exhausted and had to sit down and rest. So it is true that a mental struggle can be just as exhausting as chopping wood!

Aleksander Perski
Stress researcher at the Karolinska Institute in Stockholm

(The original text is in Sällskapet San Micheles Vänners Medlemsblad, February 16, 2006)