PTSD is characterized by recurrent and uncontrollable memories of extremely negative experiences. The condition is commonly seen in victims of abuse, as well as individuals who had just come from very stressful environments, such as refugees and soldiers from war-torn areas. Because of this, many people have this notion that PTSD is caused by traumatic events.
The study, written by researchers from the University of Birmingham, Ruhr-Universität Bochum, the University of Konstanz, and Berlin’s Max Planck Institute for Human Development, says this isn't necessarily the case. It involved 24 refugees from Asian, African, and European countries, half of whom had PTSD while the other half didn't.
The researchers asked the participants to try and suppress neutral – not emotionally charged – memories. They found that individuals who found this task difficult were likely to have PTSD as well. Furthermore, the worse the PTSD symptoms were, the more difficulty the refugees had in suppressing neutral memories.
Interestingly, they also found that efforts to suppress the memories had a negative impact on the participants' ability to remember other experiences, even those that were not traumatic. The study indicates that PTSD is not caused by the presence of traumatic memories, but by dysfunctional gamma frequency activity in the sufferers' brains.
”Difficulties experienced by people with severe PTSD symptoms when attempting to suppress bad memories is linked to the ability to regulate gamma frequency brain activity,” said Simon Hanslmayr, one of the authors.
”This novel biomarker could help identify risks posed to PTSD patients by memory suppression techniques and assist in adapting and developing psychotherapeutic methods. Our study certainly raises concerns about unwary use of memory suppression in treating PTSD sufferers,” he added.
Indeed, there are attempts to treat patients of PTSD by having them “forget” their traumatic experiences. This study suggests that doing so might cause more harm than good. In fact, a separate and earlier study, published in the journal Nature Communications, says suppressing traumatic memories can result in a “virtual lesion” in the patients' brain that impairs their ability to form new memories, essentially giving them amnesia.
The researchers note that more research is needed to determine the effects of traumatic stress on the brains of refugees. Not only will it reveal new and more effective ways to deal with PTSD, but it would also help in the creation of better strategies for solving the challenges posed by the increasing number of refugees.
Gamma frequency and memory formation
Every day, the movement of electrical pulses from one neuron to another produces different types of neuronal oscillations or brainwaves. These brainwaves vary in terms of frequency and function and are present even as a person sleeps.
Gamma waves are a mystery of sorts. Unlike beta frequencies that are accessible throughout much of the day and alpha frequencies that occur during meditative, relaxed states, gamma frequencies are fast and inaccessible. They occur in split seconds when information is transported quickly and quietly from one area of the brain to the other. Some experts link gamma waves to “aha” moments – those very quick, fleeting moments of sudden discovery and inspiration when one realizes the answer to an especially challenging question.
Research into the role of gamma frequencies in the formation of memories suggests it is connected to visual memories. In fact, researchers, in a study published still in Scientific Reports, note an increase in both alpha and gamma frequencies as the brain anticipates the task of remembering images. In normal brains, the alpha phase ultimately proves stronger than gamma power. This difference is associated with the proper formation of memory.
Another study, found in Brain, reveals that in people with PTSD, the association between alpha phase and gamma power is reversed – the latter is more heightened than the former. This results in sensory hyperactivity and the absence of control over impulses, overloading the frontal brain and leading to many of the symptoms associated with PTSD.
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