Post-traumatic stress disorder (PTSD) is a scourge for anyone who suffers from it. The symptoms are heartbreaking – nightmares, flashbacks, poor sleep quality, irritability, and a lack of concentration. Some will feel disconnected from reality as they perceive being trapped in a mental cage from which they cannot break free.
While medical professionals can identify the outward signals of PTSD, finding the inner cause has been difficult at best. Researchers have tried for decades to determine the cause at the psychological and eventually the neurological levels of human existence. In the latter, several factors have been associated with the onset of illness ranging from serotonin and cortisol levels to altered electrochemical signalling in the brain. Some models have been developed in an attempt to explain how PTSD may come about yet none can offer an explanation as to how that trap forms and why it is so hard to break.
There may, however, be a breakthrough in understanding the PTSD “mental cage” thanks to a Defence Research and Development Canada project at the Hospital for Sick Children in Toronto, Canada. The research team, led by Dr. Elizabeth Pang, have taken a different approach to examining the effects focusing on the brain in real time. Their results, which were published earlier this year in the Journal of Neuroscience offer a novel perspective on how traumatic events constrain the mind.
The team wanted to examine PTSD at the level of brain processing. For Pang’s group, the most effective route was magnetoencephalography, or MEG. As the name implies, the goal is to measure the neuromagnetic field in the brain and then record brain oscillatory and amplitude changes. With each reading, they could properly determine where the brain was most active and also which areas remained relatively silent.
This wasn’t the first time MEG was used to examine a symptom of PTSD. Back in 2013, the technique helped to understand how trauma affects emotional processing. The results provided some perspective on why sufferers seem to be closed off. The threat detection mechanism is raised – as one might expect – and eventually a network is developed in the pre-fontal cortex to anticipate danger rather than fully process the stimuli.
A few years later, Pang and Taylor’s group expanded on this discovery by using MEG to provide a more comprehensive understanding of the fear factor over time. The results suggested those confirmed to have psychological PTSD had higher amplitudes of response to neutral stimuli as compared to those without the condition. This suggested the neural patterns, particularly in the first few milliseconds after a stimulus, such as a word or image, were somehow changed.
Pang and Taylor’s most recent study focused not on the response to stimuli but on the mechanism of processing. To do this, they invited military volunteers both with and without PTSD as well as civilians with and without mild brain traumatic injury. The separation of these individual types could offer perspective on the difference between PTSD and brain injury. If the team were right, all four groups would end up showing distinct processing profiles.
Once the volunteers were chosen, they were monitored as they were asked to view a variety of stimuli in the form of images and words. The MEG profiles were collected and then analyzed to determine both the location of the magnetic fields and also the frequencies to assess mental function in the brain. Once this was completed, the team could then examine the differences between the four groups.
When the results came back, those suffering from PTSD appeared to be consistently engaged in a mental loop of brain activity. Based on the frequencies, the team realized these processes were associated with memory and information processing. This overabundance of one type of frequency prevented others, including those linked to conscious thought, from being used appropriately. It’s why PTSD sufferers did not respond as strongly as those without the condition to the various stimuli.
The examination into the difference in frequencies also provided some perspective on how those with PTSD suffer. They are locked in a world of memories and continual processing with no apparent means for escape. This would directly impact their ability to fully experience the stimuli of the environment affecting the quality of their lives. Over time, this inability to function in the social context could eventually erode other aspects of self-esteem and self-worth leading to anger, aggression, depression, and self-harm.
The results do, however, open a door to possible future treatment options. By helping to balance out the frequencies, the effects of the trap may be lessened and a person’s quality of life may improve. Although no indicated treatments are available at the moment, the use of MEG may be able to help speed up the search for the right key to that mental cage and provide these people a better quality of life.
Mišić B, Dunkley BT, Sedge PA, Da Costa L, Fatima Z, Berman MG, Doesburg SM, McIntosh AR, Grodecki R, Jetly R, Pang EW, Taylor MJ. Post-Traumatic Stress
Constrains the Dynamic Repertoire of Neural Activity. J Neurosci. 2016 Jan 13;36(2):419-31. doi: 10.1523/JNEUROSCI.1506-15.2016. Erratum in: J Neurosci.
2016 Feb 17;36(7):2323.
Text by Jason Tetro, for CAN-ACN