i am drowning in administrative paperwork crap. and it's not the standard administrative paperwork crap. no, it's that on anabolic steroids.
also, learning how to deal with some new software that might as well be written in a language i don't understand.
where did my science go?!??! when is it coming back?! and how do i handle all this plus the science when it does come back?
My last few posts have focused on stress/anxiety disorders. It's hard to cover the neuroscience behind these complex disorders in just a few posts, because there are so many changes going on and so many angles from which one can approach them in the first place. I didn't even get into the neuroendocrine stuff, because that is probably 2 posts on its own. Suffice to say, the short-term changes that manage to keep someone going through a tremendously stressful event don't always snap back to day-to-day life so easily. Sometimes intervention is required. ASD has the potential to progress to PTSD if not treated. PTSD can be a chronic, debilitating condition.
FDA-approved drugs
Sadly, we haven't found many effective drugs to help with stress disorders. I think the neuropharmacology research world has a long road to travel on this end of things. The two approved drugs are paroxetine and sertraline- both SSRIs, or selective serotonin reuptake inhibitors. They work by prolonging the time that the neurotransmitter serotonin stays in synapses. You may have heard of their common use for depression. Though there are depressive-like elements to PTSD, these are two quite distinct disorders. However, they may share some common mechanisms in the brain that make SSRIs potentially useful in both cases. But SSRIs do not work for everyone.
Off-label use
There are a handful of drugs that are used off-label as well. These drugs haven't been approved by the FDA specifically for PTSD, but have been approved for another use that may be related to stress disorder symptoms. Sleep aids (zolpidem and eszopiclone are two examples) work by increasing inhibitory tone in the brain. Adrenergic antagonists like propranolol work to blunt the sympathetic "flight or fight" response. They block adrenergic receptors, so when the body produces a lot of epinephrine (adrenaline) the stress response is reduced. They might be useful in reducing the constant vigilance. Several of these off-label drugs are in clinical trials specifically for use in PTSD.
Non-drug therapy
There are therapies available that do not make use of drugs, however, they can be used in combination with a drug treatment regimen. Two types of cognitive-behavioral therapy so far seem to help make progress: prolonged exposure therapy and cognitive-processing therapy.
Current studies
Many clinical studies are underway for new potential therapies to assist with PTSD. These include pharmacological and non-pharmacological approaches. A few of the more interesting ones are:
For more resources, I highly recommend checking out the National Center for PTSD's webpage. And as always, if you feel that you might require medical attention, please do not seek help from blogs or other internet sources, but see your doctor for appropriate medical evaluations.
As you may have seen, there have been some site issues at Scientopia recently. Our admin has been working very hard on coping with the stupidity cast toward us by a hosting company and straightening out all the fallout. Kudos to MarkCC for all his hard work!
I've also had a bit of a work-takeover-of-life recently- what a surprise. But we're gonna get back on track here with the blogging as I reassemble my usual routine.
In the last post, we looked at some of the areas in the brain where stress reactions occur, and their interactions during a typical acute stress reaction. Now, we examine disordered stress, and the changes reflected in brain signaling.
What are the disorders of stress response?
Acute Stress Disorder (ASD):
An acute (2 days – 4 weeks) experience of the below symptoms, within a month of experiencing a severe trauma (defined as a situation where one witnessed or experienced something very distressing, a loss of control over traumatic circumstances, the possibility of losing one’s life, and similar.)
Post-traumatic Stress Disorder (PTSD):
A more chronic, lasting experience of those symptoms compared to ASD.
Generalized categories of symptoms:
Intrusive memories
Avoidance of related memory triggers, general numbing of feelings
Hyperarousal (increased vigilance of surroundings, for example)
Symptoms disrupt normal day-to-day function
**A note: this is not intended to be medical advice, nor should it be taken as such. If you are concerned about any medical condition you think you may have, please contact your doctor for professional advice.
Many of us start to think of military veterans coming home from conflicts overseas when the topic of PTSD comes up. Indeed, that is a serious issue facing returning soldiers coming back to their lives at home and it deserves every ounce of the attention it gets. But I also want to take a moment to point out that PTSD is not just for people who have seen combat. Roughly 7% of the general US population lives with PTSD, which can arise from car accidents, incidents of violence, childhood abuse, and many other experiences one can have without even leaving one’s hometown. So this is something that could potentially affect anyone.
Adaptations in the brain
As I've probably mentioned more than enough times, stress disorders represent an adaptation to survive a tremendously stressful situation, without the re-adaptation back to a usual level of stress reactivity afterward. The result is a continued stress response even after the context/reason for stress has ended. Recall that we’re talking about 3 major brain areas that interact during a stress response, but also that these are not the ONLY brain areas that are involved.
We have the amygdala (the fear/emotion responder), the hippocampus (event memory), and the prefrontal cortex (behavioral control) interacting to produce a response to aid in avoiding/escaping a harmful situation. Normally, these three areas work together to help you get out of a bad situation and then resume normal function. But this isn’t always the case. Sometimes the brain over-responds and doesn’t adapt back to typical function so easily.
Normally, we have this nice little response as diagrammed below. The amygdala responds to fearful/emotional cues in the environment, and that triggers some strongly encoded memories of the event in the hippocampus. The hippocampus and amygdala responses to stress dampen the behavioral inhibition from the prefrontal cortex. Hopefully very soon thereafter, you've escaped from whatever stressor was threatening you, and usual function resumes.
But in ASD or PTSD, the brain’s adaptation to the environment doesn’t resume usual function, and the result is that fear/emotion area has adapted to be especially responsive. Meanwhile, the other two arms of the circuit are weakened. The representative balance between the three brain regions we're looking at here changes to this:
Where the amygdala is less inhibited and fires more, it alters the timing of neurons firing in the hippocampus, which makes for weaker encoding of new memories and weaker inputs to the PFC. The reduced inhibition from the PFC lets the amygdala continue firing more, which relays to the hippocampus, and further reduces the inhibitory signal coming from the PFC. The checks and balances between the three regions are weakened substantially. At this point, reminders of the event trigger an inordinately strong emotional reaction in this signaling pathway, while "un-learning" or extinction learning is weakened. This reaction results in some of the symptoms of stress disorders- a reminder triggering the sense of re-living the event, for instance. Of course, there are other brain areas contributing here, and I don't want to discount them. But this is a pretty substantial shift of normal signaling!
But just because a signaling pathway in the brain is adapted to work differently from normal doesn't mean it is permanent. There are some treatments available now and others coming up that might provide help and support for people who are dealing with ASD or PTSD. We'll take a look at some of those next time.
we've got some temporary server issues, and for the time being, commenting is disabled. fear not, dear readers, it will be back soon!
Last time, we got started with a discussion of stress reactions and brain adaptations. Now that I’ve covered some of the more general stuff, let’s dive into the neuroscience! Leigh loves the neuroscience.
It’s safe to say that many, many parts of the brain are involved in responding to stressful things. We know a lot, but we don’t know it all. I’m going to focus on the major players in this response, but as always, this is not a comprehensive list (because I’m not writing a book here).
Let’s meet our contestants:
Amygdala- Named after the almond (and most definitely not a part of the built-in dictionary in my word processing program), the amygdala is a whole series of cooperative little nuclei in your brain. Their job is to convey emotional reactions, particularly fear reactions, in response to what’s going on around you. The result puts you on high alert.
Hippocampus- I’ve already proclaimed my love for the hippocampus, but I’ll do it again. This part of your brain is awesome. Among other things, it’s involved in learning associations with places, events, sensory inputs (sounds, sights, etc) and other aspects of experiences and settings. As the hippocampus processes these pieces of information together, you form memories of places and the events that happen in those places. After the associations are made, memory modification through re-consolidation and extinction learning are also going on in the hippocampus.
Prefrontal cortex- Ever had a bad day and managed to restrain yourself from throwing things left and right? Thank your prefrontal cortex. (Unless, of course, you ended up going ahead and throwing things anyway.) Your prefrontal cortex is involved in all sorts of thinking things through: decision-making, calculating consequences of actions, looking to the future. In short, some high-end judgment call processing goes on up there.
The three of these areas have a lot of interconnections! The amygdala outputs affect the hippocampus, outputs from the hippocampus can modify signaling in the prefrontal cortex, which in turn is able to suppress the amygdala. And so on and so forth, creating an extensive set of interactions between these three centers of stress reaction. Each of these areas changes its output in response to inputs from other areas! These responses, in concert with many others taking place during stressful situations, prime us to stay alive under adverse or threatening circumstances.
Figure 1. Like three interconnected peas in a pod. Except, in your brain.
When you're involved in a frightening situation, you observe situational cues that help you to identify that the situation is not a good place to be. Your amygdala helps you to recognize these cues as fearful. The amygdala's response sends signals to the rest of the brain that something strange is going on. Your hippocampus takes up the cue to remember this situation- in case you should ever encounter those circumstances again, you can remember it and stay away from something potentially dangerous. The effects of the hippocampus and amygdala stress responses dampen activity in the prefrontal cortex, lessening its function in suppressing emotional responses during the stress episode. The result is a quick series of brain changes that increase your alertness and help you to dart away from a source of danger.
Stress reactions are a short-term situation most of the time- the body adapts for the duration of the stressful stimulus, and it re-adapts once the need for the stress reaction ends. Unfortunately, things don’t always work like we expect them to. Those homeostatic mechanisms protect us, that increase the likelihood that we get through those stressful situations, can harm us in the long run.
The downside is that sometimes, those system adaptations don’t always make their way back once the need for the stress reaction passes. And that's our topic for next time.
Your daily experiences shape who you are, and they shape your brain too! Neurodynamics explores the dynamic brain and its adaptive responses to all kinds of inputs.
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