Corticomedial amygdala lesions, behavior, corticosterone, and prolactin: unexpected separation of effects

The present experiment examines hormone: behavior relationships following lesions of the amygdala. Affective behavior and levels of corticosterone and prolactin were compared in rats with lesions of the corticomedial amygdala and in nonlesioned and sham-operated controls. Animals with lesions of the corticomedial amygdala were found to be hyperreactive, but to have normal corticosterone and prolactin resting levels and responses to stimulation. The unexpected separation of behavior and hormone responses is compared with behavior and endocrine changes seen following other limbic system lesions, and the implications for the psychoneuroendocrinology of stress are discussed.