The brain is the central organ of stress and controls the adaptation to stressors, while it perceives what is potentially threatening and determines the behavioral and physiological responses. Post-traumatic stress disorder (PTSD) is a mental health disease in which an individual has been exposed to a traumatic event that involves actual or imminent death or serious injury, or threatens the physical integrity of the self or others. The effects on the brain caused by stress for people with PTSD are the main subject of this paper. A literature research was conducted to see how stress affects the brain and how regions of the brain are distorted by an excess of myelin, which is formed by oligodendrocytes, in people with PTSD. Network-Oriented Modeling perspective is proposed as an alternative way to address complexity. This perspective takes the concept of network and the interactions within a network as a basis for conceptualization and structuring of any complex processes. It appears myelin, and the oligodendrocytes which produce the myelin can have altering effects in the brain of patients with PTSD. The fear response is increased significantly and the forming and retrieval of memories is also disrupted. As the effect of myelin is decreased in the model, the effects are also decreased. The main purpose of this paper is providing insight into what the effects of myelin excess might be for patients with PTSD, and simulating these effects to make these insights easily accessible.