Post-traumatic stress disorder is an extremely serious psychological conditions that develops due to traumatizing life events. It can be seen 10-35% of war veterans and 5-8% of the entire nation (Gouveia et al. 2019). The condition consists of debilitating intrusive thoughts that lead to severe anxieties, fears, depression, and instances of hyperarousal. Unfortunately, PTSD isn’t just damaging for the patient who has it, the condition can impact family members and friends. Modern day medicine primarily focuses on emotional regulation of the patient, implementing procedures or medicines to reduce the emotional state of the individual. Common techniques in treatment approaches involve psychotherapy, pharmacotherapy, and possible neuromodulation procedures like deep brain stimulation and transcranial magnetic stimulation are in clinical research stages.
Psychotherapy methods like cognitive behavioral therapy may be the most effective at actually treating fear memories. Pharmacological interventions and current invasive procedures may be effective methods at emotional regulation in response to the fear, but doesn’t actually serve as a remedy to the physiological mechanisms that underlie PTSD. The brain encodes life events, and summarizes the emotion associated with it, then uses those records as prediction of how to act in the future. Stephanie Grella and her team from Boston University conducted a non-clinical application study to how to exactly these specific fear memories could be manipulated and redefined at a molecular level. Male mice were conditioned to shocks to simulate negative fear memories and then shown conspecific females to illicit positive memories. The team “combined neuronal tagging strategies with optogenetics to manipulate hippocampal ensembles to disrupt the expression of fear memory in mice (Grella et al. 2022).” It was concluded that the most effective method of memory reconsolidation was using conspecific females in a visual manner as a means to restimulate positive memories as a way to redefine negative ones. The study was never intended to test or research potential clinical methods of treatment for PTSD, however, the evidence supplied in the study supplies promising information leading up the to the idea that potentially, memories can be reconsolidated enough that the fear memory can be wiped out.
A paper from the British Journal of Pharmacology discusses certain neuromodulation methods to treat anxiety disorders and ultimately disrupt fear memories. Anxiety is characterized as avoidant behaviors and can commonly contribute to PTSD. In theory, by deciphering the internal mechanisms of how memory contributes to just one part of PTSD (anxiety), scientist is then one step closer at understanding neurological mechanism of PTSD as whole). The main area of interest is the prelimbic cortex, specifically the hippocampus and amygdala (important memory consolidation areas). Using mice implanted with DBS electrodes, the team found “molecular mechanisms in the ventral hippocampus that disrupt contextual fear memory” (Tan et al., 2021).” Dopamine (,
, and GluN2A, serotonin (5-HT), and 5-hydocyindole (5-HIAA) receptors were all seen possible contributors to suppress fear memories. This study contributed further evidence into the internal neuronal mechanisms by providing more-localized anatomical areas and the responsibility of the cells in certain memory stages.
These studies further advance the theories that memories can be altered and even erased through scientific intervention. This is huge for the clinical world of psychology because if studies can be conducted and deemed successful in the removal of negative memories within animal models, then there is a greater possibility for future human neurological methods to remove fear memories within human patients. Thus, possibly providing patients immediate relief in a much more time-efficient and hopefully affordable way. Today, the best forms of treatment of PTSD include a combination of techniques like pharmacology as means of neuromodulation while using therapy to reperceive memories in patients so they become non-life threatening. However, these methods take lots of money and time, lengthening the road to any sort of recovery. Could invasive methods like DBS give life back to those who need it the most? More research is definitely needed to differentiate how cells contribute to behaviors, but achieving a cure is closer than it has been ever before.
WORKS CITED
Gouveia, F., Gidyk, D., Giacobbe, P., Ng, E., Meng, Y., Davidson, B., Abrahao, A., Lipsman, N., & Hamani, C. (2019). Neuromodulation Strategies in Post-Traumatic Stress Disorder: From Preclinical Models to Clinical Applications. Brain Sciences, 9(2), 45. https://doi.org/10.3390/brainsci9020045
Grella, S. L., Fortin, A. H., Ruesch, E., Bladon, J. H., Reynolds, L. F., Gross, A., Shpokayte, M., Cincotta, C., Zaki, Y., & Ramirez, S. (2022). Reactivating hippocampal-mediated memories during reconsolidation to disrupt fear. Nature Communications, 13(1). https://doi.org/10.1038/s41467-022-32246-8
Tan, S. Z. K., Poon, C. H., Chan, Y., & Lim, L. W. (2021). Prelimbic cortical stimulation disrupts fear memory consolidation through ventral hippocampal dopamine D 2 receptors. British Journal of Pharmacology, 178(17), 3587–3601. https://doi.org/10.1111/bph.15505
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