PTSD	posttraumatic stress disorder
DSM-V	Diagnostic and Statistical Manual of Mental Disorders, 5th ed.
fMRI	functional magnetic resonance imaging studies
US	unconditioned stimulus
UR	unconditioned response
CS	safety signal
vmPFC	ventromedial prefrontal cortex
HPA	hypothalamic-pituitary-adrenal
CBT	cognitive behavior therapy
GABA	gamma-aminobutyric acid
vmPFC	the ventromedial prefrontal cortex
DSM-IV-TR	Diagnostic and statistical manual of mental disorders, 4th ed. text revision
CS+	conditioned stimulus
CR	conditioned response
SCR	skin conductance response
CS+	threat signal
dl	dorsolateral
BDNF	brain-derived neurotrophic factor
NMDAR	N-Methyl-D-aspartic acid receptor