In some ways, PTSD seems no more than an exaggeration of the normal stress response because they both share similar characteristics:
- Avoidance behavior
- Increased arousal & vigilance
- SNS activation
- Release of cortisol by adrenal glands (Bear et al., 2001).
Some psychologists refer to this particular constellation as an activation of the “fear network”
(Armony & LeDoux, 1997; Tryon, 1999) or “fear structure”
(Foa, 1997), which they argue reflects a normal reaction to an abnormal situation. Bear et al. (2001) catalogue the typical SNS response involving the processes in Table 2.
Table2
Spinal control of Sympathetic Division of Autonomic NervousSystem governing responses to fight, flight, fright, and sex
| Thoracic nerves |
- Dilate pupils
- Inhibit salivation & tearing
- Constrict blood vessels (and raise blood pressure)
- Relax airways
- Stimulate glucose production and release
from liver
- Inhibit digestion
- Stimulate secretion of epinephrine and
norepinephrine (hormone neurotransmitters) from adrenal medulla
|
| Lumbar Nerves |
- Constrict blood vessels in the gut
- Relaxes urinary bladder
- Stimulates orgasm
|
| Primary SNS neurotransmitter |
- Norepinephrine (from which epinephrine is made)
|
Note. Adapted from “ANS Circuits” by Bear et al., 2001, Neuroscience: Exploring the Brain, 2nd ed., pp. 507- 511.