PTSD
posted by jenni on April 23rd, 2015 at 2:59PM

an abnormally functioning hippocampus may account for some of the cognitive symptoms of PTSD, such as declarative memory deficits. In addition, because the hippocampus is critical for context conditioning, an impaired hippocampus may facilitate generalization of learned fear in contexts unrelated to a previous traumatic exposure and impair the ability to discriminate between safe and unsafe stimuli. In combination with exaggerated amygdalar responses seen in patients with PTSD, a limited capacity for discerning threat due to hippocampal and amygdalar dysfunction may promote paranoia, hypervigilance, behavioral activation, exaggerated stress responses, and further acquisition of fear associations. Disrupted prefrontal cortical function may then serve to facilitate PTSD pathology further as a result of deficient suppression of stress responses, fear associations, and extinction.

http://www.ncbi.nlm.nih.g...cles/PMC3182008/  

http://en.wikipedia.org/w...i/Hypervigilance  


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if the traumatic experience is severe enough these biological changes in the brain (ie the excessive production of neurotoxins such as cortisol) can cause the hippocampus, in effect, to shut down.

This means it can no longer regulate or switch off the FEAR PRODUCING AMYGDALA,   causing the latter brain structure   to go into overdrive.

Thus, a situation arises in which the AMYGDALA BECOMES OVERACTIVE DUE TO THE UNDERACTIVITY OF THE HIPPOCAMPUS. Without proper intervention, this state of affairs may persist for many years.

The processes described above can lead to what has been called a TRAUMATIC CASCADE, causing the individual to feel a constant state of hyper-arousal, hyper-vigilance, anxiety and fear, perceiving danger, or the threat of danger, everywhere.

http://childhoodtraumarec...ns-in-the-brain/

Link