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I first learned about the amygdala from Daniel Goleman's famous book, Emotional Intelligence.  He makes repeated reference to this part of the brain in his description of 'neural hijackings', in which the brain detects a threatening situation, and provokes flight/fright/freeze responses, flooding us with emotion.

It is always dicey to speak of any part of the brain as doing or causing anything because the brain is much better viewed from a systemic perspective, with various parts functioning simultaneously. Nonetheless, there is an association between the amygdala and emotion, and as long as you don't start thinking the amygdala is where emotion is, or emotion is what the amygdala does, it is a useful association to bear in mind.

The following pretty picture from How Stuff Works gives us some sense of the amygdala's relative location in the brain. It is part of the limbic system and associated with automatic rather than controlled processing.

Amy, as  I like to call her, came back to mind recently when I read the following study suggesting that those with larger amygdalae have larger and more complex social networks.

I found it curious that the amygdala appears to be key, because I previously associated this part of the brain with emergencies, rather than networks, and it briefly made me wonder if people with larger and more complex social networks might be drama queens who need constant and varied reassurance.

More seriously, it is worth considering potential trade offs. If you want Amy to be big, something else may have to be smaller. Brain matter is expensive in evolutionary terms, so usually if one part of the brain is ‘bigger’, or, more technically, has more ‘functional plasticity’, this is compensated for elsewhere.

This idea of trade offs became prominent with the finding that London cabbies had larger mid-posterior hippocampi (relating to spatial memory) suggesting a neural correlate for expertise. However, they struggled to break old habits, take new routes etc., relating to smaller anterior hippocampi, a neural trade off.

A more affecting example is oral memory in certain traditional cultures i.e. shared stories and songs, and how the ability to remember them is directly undermined by literacy. A similar point is made by William Dalrymple in his wonderful book on Indian Religious practice, Nine Lives.

This point about losing oral culture has some relevance for RSA Connected Communities actually, because some argue that literacy, for all its massive life enhancing gains, undermines the cohesive, bonding function of oral stories and songs that communities tend to ‘lose’ when they are written down.

Then Amy got me thinking again, when a colleague forwarded a story describing an important recent study on meditation. In addition to being yet another strong piece of evidence in support of mindfulness, one of the main findings is that people who regularly meditate shrink (reduction in grey matter) their amygdalae, an area, the article reminds us "connected to anxiety and stress".

So here is a troubling pseudo-equation to ponder:

Bigger amygdala linked to larger social network

Smaller amygdala linked to lower stress.

Therefore...what?... the key to being less stressed is to know fewer people?

Clearly that is not right, but it seems to be what 'Amy' is telling us, so perhaps she has gone G'dala.

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