Page 484 - Total War on PTSD_FINAL

on time. As such, selected stimuli is processed — those directly related to the goal of arriving on time. Environmental details that an individual would normally notice and process are passed by obliviously. In patients with PTSD, this type of constriction is an everyday experience due to the hyper-vigilance and hypersensitivity the condition instills in the patient.
For simplicity, you can think of two main nervous systems –- an internal one that controls our organs, fluids and rhythms, such as blood pressure or heart rate, and an external one that relates to our outside world. There are actually many smaller ones that work in harmony. When a person is involved in an activity, eventually other processes such as hunger and fatigue take over and thereby limit how long a person can function. The mind can override hunger and fatigue for a bit, but in the long run, the body signals are in control.
The eye is part of our external nervous system, yet heavily connected to the internal nervous system. When it becomes hyper-sensitized, as it does in PTSD, a person sometimes is unable to deal with the outside world, because he or she perceives external stimuli differently. The information passing through the retina into the brain evokes internal nervous system responses that do not occur for healthy individuals. Blood pressure rises; stress chemicals including adrenaline increase. A person’s whole being is disrupted, placed in an abnormal “fight-or-flight” state. Developed skills can be lost and need to be regained.
By directing light onto different portions of the retina, environmental signals are routed through different cortical lobes on their way to the visual cortex. The balance of signaling pathways is affected and changeable. Such lobe activation can be verified
484 of 837