The goal of this article is to describe some of the central nervous sy
stem circuits involved in the regulation of the hypothalamo-pituitary-
adrenocortical (HPA) axis, with an emphasis on animal models believed
to mimic the human experience of emotional stress. First, the basic co
nstitutive elements of the HPA axis that control glucocorticoid secret
ion are reviewed. A description of the neural systems assumed to regul
ate the activity of the HPA axis, both anatomically and functionally,
follows. It is argued that hypothalamic, septal and bed nucleus of the
stria terminalis neurons are involved in the regulation of the HPA ax
is by situations eliciting emotional responses.