Your Brain, a Process Called Homeostasis, and Post-Traumatic Stress: A Conversation Starter

(NOTE: This is the first in a hopefully never-ending stream of guest posts from friends of mine. This one is by Science Firebird, who is a research science officer. She did a PhD while her friends did overseas tours, and that stuck with her. Now she does research in recovery from deployment-related health conditions. She’s incredibly smart, and you can follow her on Twitter, @SciFirebird.)

You’ve had it all your life. Everywhere you goes, it goes. It shapes you and you shape it. You go to war, it goes to war. Your combat helmet helps, but it doesn’t protect against everything. You come back… commence the game of push and shove in your head.

The brain is an astounding organ. Sometimes you may disagree with the things yours does (and don’t we all), but if you’re alive today, it’s in large part because of the way your brain has adapted to the environments you’ve passed through on your journey through life. It’s shaped for response, adaptation, and survival. It primes your behaviors for the same.

The thing is, it’s also complex and multi-factored and operates in ways that are to some extent dependent upon your cumulative individual experience- and to make things that much more confounding, it turns out that initiating a survival response is a little more straightforward than reversing that response. You’re alive, mission accomplished, what pressure is there for your brain to return to its pre-deployment state? You’re primed for life or death already.

Despite the talk of complexity and general holy-shit aura surrounding the topic of brain research, we do have a pretty solid basis of knowledge to work from over here. It’s not magic, after all, it’s physiology. We know the brain works in a predictable fashion. We know what drives motor activity, what drives higher cognition, what regulates body temperature, where we process threat stimuli and how we form memories, as examples. These things are the same for us all and
across species. These brain regions work together to produce a given output: say, threat response can shape memory (and in absolute terms, that could go anywhere from a more robust memory to having little memory of the actual event). These things are becoming well understood enough in the research lab that the end result is a slew of tiresome, poorly written science news headlines proclaiming “[Insert Thing Here] Rewires The Brain!”– yeah, well, simultaneously not at all and also no shit. Because the brain may maintain the same wiring diagram pattern, but it is continuously updating the strength of those connections between regions in terms of how relevant they are. This process of response and adaptation to external pressures from the neuronal network level all the way down to the cellular component level is called homeostasis, and without it we would not exist as a species.

Think of a road map. If you’ve got a mass of people commuting from the suburbs to the city, eventually they’re gonna widen the main highway to respond to demand. It’s a little bit like that. (Unless you live in the DC metro area, in which case all these dimwits do is add toll lanes.)

So here’s the bottom line. If you spend a year in an environment where people want to harm you, then you’re going to adapt to become hypervigilant to any sign of danger in your surroundings, for instance. This is a pretty expected kind of response- it’s your brain keeping you as alert as possible to threats and therefore helping you stay alive. I’d wonder a bit about anyone who didn’t respond that way. The key issue, however, is this: once you leave that place and no longer need that hypervigilance, if your brain doesn’t get the “simmer down now” signal and do so on its own via homeostasis, how do we facilitate ramping that vigilance back down to where it used to be?

That’s where the researchers have a lot of work left to do, and the clinicians are struggling for a stopgap tool in the meantime. I wish I had a well-placed bit of snark that would make this fact suck less than it does. Nothing can mitigate the huge sigh of “fuuuuck” that wells up in my mind when I look up for a moment from my daily grind and look at the bigger picture.

But about that bigger picture.

A vexing part of being on the research end here is that the basis for a PTSD diagnosis is grossly suboptimal for research. Our docs are diagnosing based on exposure to a traumatic event- this happens to lots of people in all sorts of places and situations, and not everyone who is exposed ends up with lasting effects. But beyond the basis as exposure to a traumatic event, there is the wide and varied types of responses that are included. It’s my opinion that the definition of PTSD is very wide and needs to be subcategorized, at the least. I think we are looking at a spectrum of diagnoses here, and they are currently running under one definition. It’s very hard to replicate any human condition in a preclinical model in the first place-(and in case this isn’t clear why one would do this, it’s because we can do the best mucking around in brains preclinically)- but when you set very wide goalposts and handwave away accuracy, you essentially are dismissing precision. Without precision, in my world, you’ve got nothing but a mess of data that becomes increasingly hard to assemble into a single coherent direction to drive forward. Without preclinical work, you don’t have clinical studies, and you struggle to assemble something that will help people out down the road.

So what am I trying to tell you here? Lots of things. What’s my hope for the future? I’m working on that.

But I can tell you this much. There’s not going to be a “take this pill every morning and your life will return to the way it was” problem solving approach here. I do think there will be a “take this pill before you go to your therapy session” or “take this pill after you successfully negotiate a difficult situation in the clinic or on your own” approach coming down the line. Because what causes this is an experience-dependent process, I think that so will be the path toward resolution.

After all, you go to war with the brain you have.

Ed: An interesting and thoughtful take on PTSD from an Army scientist is a pretty effin’ cool thing to have. It feels as if she could be talking to or about me here, and I know plenty of vets who feel the same. I especially appreciate the use of layman’s terms and analogies, because I’m not the smartest grunt in the world, by far. What did you guys think? Feel free to comment!

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2 thoughts on “Your Brain, a Process Called Homeostasis, and Post-Traumatic Stress: A Conversation Starter

  1. I believe that one day we’ll lick this problem, but I think we’re a long way away. And I agree with you that there are different forms of PTSD, with different effects on the subjects (I hate the word ‘victim’.) Military PTSD is different than the PTSD experienced by a traffic accident victim, or a victim of a violent crime, and even crime victims probably have different experiences of the condition depending upon their specific experiences.

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    • Good point on origin of the traumatic stressor. The military command structure provides an entirely different backdrop on trauma exposure. (Although I think in this case we should separate out SF because they operate differently- they also have different rates of PTSD as a community.) It’s been a bit difficult to impress that upon some of my esteemed colleagues in the research community, and I need to continue to reinforce this point.

      Not only that, but people have focused sets of symptoms. Some feel amped up while others are numbed down, for instance. Calling these two things identical phenomena for clinical or research purposes confounds me. Why? And how do I model two opposing reactions?

      People who live with post-traumatic stress are not victims- they are survivors, trying to go about life as regular folks do.

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