Effect of pretraining amygdala lesions on behavioral, neuroendocrine, and neurochemical indices of the stress response. A shows effect of pretraining amygdala lesions on stress-induced freezing behavior. B shows effect of pretraining amygdala lesions on stress-induced serum corticosterone levels. C shows effect of pretraining amygdala lesions on stress-induced DA metabolism (expressed as the DOPAC/DA ratio) in the m-PFC. D shows effect of amygdala lesions on stress-induced freezing and ultrasonic vocalization during the conditioning period. Animals were subjected to bilateral sham (SHAM) or excitotoxic lesions of the amygdala (AMYG-) 14 d before conditioning. STRESS and NO STRESS indicate experimental conditions in which animals were or were not exposed to shock during conditioning, respectively. Number of animals per group are (A–C) SHAM/NO STRESS, 10; AMYG-/NO STRESS, 7; SHAM/STRESS, 9; AMYG-/STRESS, 10 (A) and 11 (B, C); and (D) SHAM, 9; AMYG-, 10. ****, Statistically significant difference, p < 0.0001; ***, statistically significant difference, p < 0.001; **, statistically significant difference, p < 0.01; *, statistically significant difference, p < 0.05;ND, no statistically significant difference.