Schematic illustration of the dorsomedial, dorsolateral, lateral and ventrolateral neuronal columns within (from left to right) the rostral periaqueductal gray (PAG), the intermediate PAG (two sections) and the caudal PAG. Injections of excitatory amino acids (EAA) within the dorsolateral (dlPAG)/lateral (lPAG; green) vs. ventrolateral (vlPAG; orange) columns evoke fundamentally opposite, active vs. passive emotional coping strategies. EAA injections made within the rostral portions of dlPAG and lPAG columns evoke a confrontational defensive reaction, tachycardia, and hypertension (associated with decreased blood flow to limbs and viscera and increased blood flow to extracranial vascular beds). EAA injections made within the caudal portions of the dlPAG and lPAG evoke flight, tachycardia and hypertension (associated with decreased blood flow to visceral and extracranial vascular beds and increased blood flow to limbs). In contrast, EAA injections made within the vlPAG evoke cessation of all spontaneous activity (quiescence), a decreased responsiveness to the environment (hyporeactivity), hypotension and bradycardia. A nonopioid-mediated vs. an opioid-mediated analgesia is evoked from the dlPAG/lPAG vs. vlPAG. Adapted from Bandler et al. (1994) Fig. 1 and Bandler et at. (2000), Fig. 1 with permission.