Cerebral metabolism, brain imaging, and the stress response

While neuroendocrinology has afforded us a 'window into brain metabolism', which has been exploited extensively in stress research, modern in vivo imaging, in particular positron emission tomography (PET), is able to detect very small (nano- to pico-molar) signals in brain metabolism and pharmacology, and can localize such signals anatomically within the mm-range. In this chapter we provide an overview over the range of in vivo imaging results associated with stress research. We will put an emphasis on post-traumatic stress disorder as the most important acute stress-related syndrome in psychiatry. There is, of course, an overlap with chronic and the sequelae of everyday stress, which will be duly covered. The picture is made complex by the brain being an executive organ of the stress response, but also the target of the potential damaging effects of stress, reinforcing the 'feed-back paradigm', very familiar from psycho-neuro-endocrinology.