Our autonomic nervous system influences internal organs and governs key functions such as heart rate, digestion, and temperature regulation. Psychosomatic diseases are those without clear physical basis, and are presumed to have a mental component. They are often viewed with suspicion by modern medicine because a neural link between brain areas of cognitive function and the autonomic nervous system has been lacking. Until now.
In a paper appearing in Proceedings of the National Academy of Sciences, Dum et al. have identified a neural network linking the adrenal medulla to areas of the cerebral cortex in monkeys. These cortical areas are involved in motion planning and control, cognitive function, and emotional regulation. The authors believe this circuitry can provide top-down control of the adrenal gland's release of stress hormone which govern "fight or flight" responses. They state that:
Taken together, these findings raise the possibility that the areas of the cerebral cortex that influence the adrenal medulla also are key cortical nodes of a "stress and depression connectome."
An approachable summary of this work can be found here.