Limbic Forebrain Modulation Of Neuroendocrine Responses To Emotional Stress

One major class of stress paradigms termed emotional stresses possess distinct cognitive/affective components and model the human experience of fear and anxiety. Their capacity to engage adaptive response systems, notably the hypothalamo-pituitary-adrenal (HPA) axis, requires comparison with past experience, a function fulfilled by a network of interconnected structures in the limbic forebrain, including aspects of the prefrontal cortex, hippocampus, extended amygdala, and midline thalamus. This network may exert both positive and negative modulatory influences on HPA axis responses to acute emotional stresses. These adjustments are mediated indirectly, with proximate relays having been recently identified in the hypothalamus and bed nucleus of the stria terminalis, respectively, with the latter representing a point of convergence of influences from multiple stress-inhibitory limbic forebrain structures. This same network participates in adaptations (habituation, facilitation) to repeated emotional stress, and its activity is thus relevant to the many adverse health consequences of chronic stress exposure.