The role of the central amygdala in stress and adaption.

Recent views on stress emphasise the existence of more than one response pattern to stressful events, and the importance of individual differences in coping with environmental challenges. Therefore, in the evaluation of the specific contribution of the central nucleus of the amygdala (CEA) in stress and adaptation it has to be considered whether the stress is acute or conditioned, and whether it requires active or passive styles of coping. Based on series of our own studies, we propose that the CEA is consistently involved in the organisation of processes of passive coping, reflected in immobile behaviour and parasympathetic activity. Furthermore, a differential regulation of the CEA via its peptidergic neuronal input may underlie the distinct behavioural and physiological stress patterns accompanying the different styles of coping. Additionally, the involvement of the CEA in neuroendocrine control is addressed. The CEA exerts a general, modulatory influence on the neuroendocrine control to acute stressors, whereas this output during conditioned stress seems to be independent of the CEA. The neuroendocrine state as achieved during acute stress is, via feedback to the brain, of importance in learning about the situation, and to consolidate the experience. In this review an attempt is made to provide an integrated model of CEA functioning in relation to stress and adaptation.