In honor of finishing the first semester of medical school, I thought I’d post a much more scientific look at PTSD and its effects on the brain.
The above image is taken from J. Douglass Bremner, MD’s paper: Traumatic stress: effects on the brain, published in Dialogues in Clinical Neuroscience.
Firstly, for those of you not involved in medicine, the brain has different areas that perform different functions- if you were to inhibit one tiny section of the brain or change the function of that area, the functions of that area would also be inhibited or changed (see slideshow below for helpful images depicting different brain areas and functions).
Each side of your brain contains four lobes. The frontal lobe is important for cognitive functions and control of voluntary movement or activity. The parietal lobe processes information about temperature, taste, touch and movement, while the occipital lobe is primarily responsible for vision. The temporal lobe processes memories, integrating them with sensations of taste, sound, sight and touch.
One of the landmark studies as far as discovering that the brain areas function independently of one another was in 1848 when a man named Phineas Gage had a section of his brain impaled from an accidental railroad explosion. He survived the explosion, but the section of his brain that was impaled was damaged beyond repair. He was drastically changed in his character and judgement after this incident as his frontal lobe was what was destroyed. To read more about Phineas Gage, click here.
Let’s jump to PTSD: PTSD is a stress response that “is characterized by specific symptoms, including intrusive thoughts, hyperarousal, flashbacks, nightmares, and sleep disturbances, changes in memory and concentration, and startle responses. Symptoms of PTSD are hypothesized to represent the behavioral manifestation of stress-induced changes in brain structure and function. Stress results in acute and chronic changes in neurochemical systems (norepinephrine & cortisol) and specific brain regions, which result in longterm changes in brain “circuits,” involved in the stress response.” -from Traumatic Stress: effects on the brain.
There are a few areas of the brain that are implicated during a stress response: the amygdala, hippocampus and prefrontal cortex, which, together form something called the Limbic System. The Limbic System is an area of the brain involved in memory and emotion. Click here for a video about the limbic system and its constituents.
There have been many studies conducted on PTSD but one that has consistent and shocking results administered a battery of tests (6 different tests) that tested verbal and visual memory, selective memory, recall, verbal learning, and behavioral memory to patients including those affected by PTSD from Vietnam combat, rape, the Holocaust, adults who had childhood abuse and traumatized children. The results concluded that these patients had significant deficits in verbal declarative memory but had intact visual memory and IQ.
The most important area of the brain involved in memory is the Hippocampus.
The Hippocampus is located in the medial section of the temporal lobe of the brain. It was named “Hippocampus” due to its resemblance to a seahorse (Greek Hippos means horse and Kampos means sea-monster).
The hippocampus doesn’t store memory, but rather, acts like a shipping center, taking information, processing it and then temporarily storing it until it is stored in long-term memory- all of this is massively affected by sleep.
Each region of the hippocampus plays different roles in memory processing, retrieval and storage. For example, the rear part of the hippocampus is involved in the processing of spatial memories.
Studies of London cab drivers have found that navigating complex mazes of big city streets is linked to the growth of the rear region of the hippocampus.
The hippocampus is more active during sleep after learning or training because it also helps to consolidate memories during sleep which allows better recall the next day.
How does this relate to PTSD? The hippocampus has been found to be significantly smaller in those affected by PTSD. Studies of this were doe on those affected by childhood abuse as well as in combat veterans- each study cohort was matched carefully with those who also abused drugs and alcohol to an equal extent (we already know that PTSD coping can include abuse of drugs and alcohol).
The good news is that hippocampus-associated atrophy (shrinking/dying off) of the brain and hippocampal-based memory deficits can be reversed with treatment of SSRIs (selective serotonin re-uptake inhibitors, a type of antidepressant that increases the neurotransmitter serotonin, which is involved with happiness, or at least, when low, is associated with depression).
The Amygdala is located in the medial area of the temporal lobe as well and is associated with memory of emotional events and plays a huge role in fear responses. Fear responses can vary- one of the most commonly studied fear response is the freeze-response in mice- when mice hear loud noises, they immediately freeze. We are all a bit more familiar with videos of goats freezing/fainting when they get scared, however, which can be likened to the freeze-response in mice.
Those of us who have PTSD know how weird our responses can get when triggered. If an event or occurrence in real time stimulates a fear response in me, for example, I can display a freeze response- no fainting happens luckily, but I do freeze up and feel like my feet got glued to the ground while my brain just shuts down so that I don’t have to take in what’s happening around me. This started during my abusive situation, during which, I would be publicly yelled at and degraded. After a certain amount of this type of treatment, I developed a conditioned response to just shut down and stop moving or reacting- everything goes numb and I can’t move. It’s super weird and embarrassing but it’s the reality of PTSD. Another common fear-response is curling up into the fetal position, something that is often comforting to those in distress. When I was in my abusive situation, I often came to after being yelled at and found myself curled up in a corner rocking back and forth repeating a phrase to myself like “make it stop.” It was definitely weird but I developed the response without consciously thinking about it. Responses like this can range from fetal position to instinctively hitting or punching something- for example if rape victims can instinctively perform self-defense if triggered by something that reminds them of the setting in which they were raped. As a victim of rape, I can attest to this. I’ve even been triggered while getting a pedicure by a male in a nail salon because of the amount of physical contact which, unbeknownst to myself, involves a foot/calf massage oftentimes.
The prefrontal cortex is involved in the stress response and limbic system, usually by inhibiting the amygdala, thus inhibiting fear responses. If you took the same mice whose amygdalae developed a conditioned fear response to loud noise and exposed them to that noise over and over again, the prefrontal cortex inhibits the amygdala and the mice stop freezing/reacting to the loud noise over time. The neurons (brain cells) of the prefrontal cortex are often decreased in branch number (kind of like volume or surface area of the neuron’s extensions) in animal studies and has been replicated in women with PTSD and abuse history by MRI imaging.
PTSD is a condition from hell, for those of you who don’t have this- you become a helpless victim of your brain’s circuits that only developed conditioned responses due to the environment that caused the PTSD in a vain attempt to help increase chances of survival of that situation.
I’m about two years out from my abusive situation’s end and I get triggered on a weekly basis. Granted, it’s much easier to stop the triggers from reaching a threshold point, thus preventing the actual conditioned fear response, but it’s not always possible to prevent this from happening. The first few months after my abusive situation ended, I walked around the town in which my abusive ex and myself lived together and was constantly alert. I subconsciously scanned rooms before entering them and stayed on the periphery of any room or area so that I would be better able to spot danger. I would almost pass out every time I saw a car that was the model of his car or even a car that was the color of his car. I almost passed out anytime I saw a white coat as he was a medical student, which was constantly as I worked in a hospital at the time. I had breakdowns and hyperventilated around 10-20 times each day but over weeks and months, it’s gotten better. There are still setbacks- encountering similar people or situations can massively set someone with PTSD back, but overall, it’s 5 steps forward and 2 back. For those of you with PTSD, I have taken antidepressants that have, I think, helped me along with functioning and with my memory- if any of you have questions about these or questions about your experience with antidepressants and PTSD, please feel free to message me.
So we’ve talked about PTSD and brain changes in a very shallow depth, but that’s enough for one post. I can bore you all with more details later.