I owe friend of the blog and fellow neuroblogger (who you should totally be reading, by the way) Scicurious for inspiration on this next series of related posts. I highly recommend that you go check her blog out, because she does a lovely job at explaining many neuroscience topics, especially the WEIRD science. In fact, she's just reposted a series about neuroanatomy that might be helpful background reading!
Let’s start the science in today’s post with a quote of old to set the stage.
'Selection is the very keel on which our mental ship is built. And in the case of memory its utility is obvious. If we remembered everything, we should on most occasions be as ill off as if we remembered nothing.' -William James, 1890
I’ve liked this quote since I first read it, because it reflects the importance of our subconscious mechanisms in maintaining memory. Most of the time we don’t really give a lot of consideration to the processes of learning and memory modification- they just happen as we go about our lives. When something disrupts those processes, and we don’t like the results, the importance of that stuff comes to light.
We need to have a good memory and an ability to modify it. Gaining experiences in the world doesn’t do much for us unless we can remember them! Our brains are very good at collecting associative memories for negative circumstances. Danger, pain, trauma, stress, you name it- the brain will pick up cues associated with aversive circumstances and set off a series of alarms when you encounter them again. This reaction might allow you to avoid what could be a repeat scenario of a bad experience.
But what about when associative memories aren’t so relevant to your everyday existence anymore, but everyday things bring those memories back? Say you were in a really high-stress situation and you heard terrible sounds like gunfire. When you get back to your everyday life, the sound of fireworks, or anything else that sounds like gunfire serves as a vivid reminder of that bad experience. Surely when you’re safe in your home, when that situation ends, you don’t need to have everyday things reminding you of that experience.
These kinds of severe stress reactions are not uncommon. Experiencing something terrible and traumatic is hard on you overall, and that includes your brain! Most of the time we can re-adapt out of that high-stress state after a short while, and get back to our usual baseline. But in some cases, for some people, that re-adaptation process doesn’t work as we would expect. That’s where we get into the realm of stress and anxiety disorders.
There are as many different ways to react to a traumatic experience as there are individuals in this universe. I want to make that clear. But we tend to look at collective symptoms as a disorder when they start to disrupt an individual’s normal daily life. There are a couple of different disorders associated with re-adaptation out of that high-stress state, which are distinct but related:
Acute Stress Disorder (ASD) – as you might guess, this is a short-term series of stress symptoms.
Post-Traumatic Stress Disorder (PTSD) – a more severe and generally more chronic set of stress reactivity symptoms.
Of course, the stress reaction has its origins in various places in the brain, and in the interactions between multiple brain regions. We might not know everything there is to know, and there is much work for science to continue doing, but we have a basic idea of the science going on here. Next up we’ll look at the neuroscience of stress reactions, how adaptations in stress signaling occur during and after heavy stress, and what's available for treatment of stress and anxiety disorders.