An integrative approach to the neurophysiological substrates of social withdrawal and aggression.

An integrative model of the neurophysiology of aggression and social withdrawal is proposed. A detailed overview of the limbic-hypothalamic-pituitary-adrenal (LHPA) axis is presented first, because we consider it to be a critical system that interacts with a variety of physiological processes to modulate affect-related behaviors. This detailed analysis of the LHPA axis is then used to clarify the research literature that links aggression and social withdrawal to LHPA functioning. We then review the role of amygdala and prefrontal cortex functioning in modulating aggression and social withdrawal. Particular attention is paid to how the amygdala and the prefrontal cortex interact with the LHPA system and the environment to produce specific behavioral tendencies throughout development. A brief overview of the implied methodological and theoretical model is provided. We explain how a detailed understanding of specific physiological processes is essential in order to develop appropriate research protocols. In addition, we suggest that future research should focus on the mapping of distinct integrative biosocial profiles that are related to specific behaviors during different developmental stages.