Weekly Roundup: The Amygala and Anxiety and Depression, Role Reversal for Hippocampus and Cerebellum, Pain Processing Different for Men and Women, And Your Predictive Brain

Weekly roundup of fascinating research into the brain and human behaviour

This week I have another brunch of interesting topics for you on all things the brain and behavior: some on brain regions that do things you expect or don‘t expect.

For you founding members and paid subscribers another installment of the Handbook of the Brain in Business is either already with you (founding members) or on the way. This time we‘re getting into more juicy stuff: this one starts with a look at high-performing brains and the role of IQ and other intelligences.

Photo by Robina Weermeijer on Unsplash

But let‘s get back into a topic that always generates interest: fear in the brain.

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The Amygdala - It‘s Role in Anxiety…and Depression

Many of you may know of the Amygdala. It is one of the superstars of the brain. In a negative way that is. Considered the fear centre - the term „Amygdala hijack“ also became a thing a few years ago now, to represent contexts whereby fear and anxiety override your brain.

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Research Hit: How Fear Can Get Stuck in the Brain

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However, the truth, as always, is much more nuanced. They amygdala also processes positive emotions and different regions of the amygdala, a structure only about the size of an almond (hence it‘s name - almond in Greek), are involved in different emotions.

Originally many assumed that the size of the amygdala would show an increased sensitivity to fear and threat. However the correlation is weak to non-existant. So if it is not size of the amygdala that predicts propensity to fear and threat - what is?

That is the question that a group of researchers, Shaawn Kamboj et al., of the University of California, with a viewing to understanding anxiety better wanted to answer. Rather than look at structures and regions they analyzed the genetic expression in various regions in the amygdala and compared this between primates, humans, and rodents. Analyzing genetic expression gives a much more refined view of brain structures but also deep clues of the behavior of neurons. What previous research has found is that different regions can have different cell types within one small region and these can sometimes have opposing functions.

What they found is that there is group of cells called intercalated cells which sit on the edge of the amygdala and express the gene FOXP2. this is particularly interesting because it is known that these act as gatekeepers, letting Informationen in or out of the amygdala. What’s more these can be targeted with medication. That opens up new understanding of anxiety and anxiety disorders. It may not be your amygdala, but your gatekeeping cells that are too active letting in and out too much information at the slightest impulse.

That in itself is fascinating but another piece of research, recently out, also looked at depression and the amygdala. Yes, the amygdala is also involved in depression. And the researchers also found something interesting here at the micro level.

A team of French researchers, Mathilde Bigot et al. of the Pasteur Institute, studied mice with depressive symptoms while observing the amygdala at the neuronal level. And yes mice can exhibit depressive symptoms - in mice it means increased anxiety, lower self grooming, staying close to walls, preferring the dark, but also lower positive responses. General negativity in us humans.

What the researcher found is that groups of neurons and circuits that encode positive emotions were suppressed and those involved in processing negative stimuli were more active. This is what is leading to this general negativity found in those with depression. This could also lead to more effective drugs - remember up to 30% of those with depression are not responsive to standard drugs.

So it seems that the amygdala is involved in more than previously thought. But a number of other well-known brain regions had been shown to be involved in more than previously thought also:

The Hippocampus normally associated with memory but implicated in skilled movement, and the Cerebellum normally associated with the aforementioned skilled movement, but shown to be important for social and cognitive function also.

Role Reversal for Brain Regions

It‘s not really role reversal but a more refined look at how some brain functions work and shows us how interconnected the brain is in many activities.