Herman, J.P.*; Ziegler, D.R.; Cullinan, W.E.: Neurocircuit Regulation of the Hypothalamo-Pituitary-Adrenocortical Axis

Regulation of the hypothalamo-pituitary-adrenocortical (HPA) axis is coordinated by an elaborate neurocircuitry controlling activation of parvocellular neurosecretory neurons resident in the hypothalamic paraventricular nucleus (PVN). Recent studies in our laboratory suggest that neurocircuits controlling HPA axis activity are stressor-specific: rapid responses to physical challenge (systemic stressors) primarily traverse brainstem circuitry, whereas responses to brain-assembled (processive) stressors involve multisynaptic connections between the limbic system and PVN. Our recent work indicates that limbic control of HPA activity involves a diffuse innervation to collections of PVN-projecting cell groups in the basal forebrain and hypothalamus, particularly in the perinuclear zone of the nucleus itself. In all, control of HPA responses to brain-built stressors appears to require communication with hypothalamic regions controlling homeostasis, allowing the brain to be advised of ongoing physiological status prior to initiating stress responses to psychological stimuli. Supported by MH49698, AG12962, IBN9814400 and MH60819.