Protective environments and health status: cross-talk between human and animal studies.

Although aging populations tend to have increased prevalence of a diversity of diseases and disabilities, there are substantial numbers of people who, nevertheless, maintain good health into old age. Human studies frequently demonstrate associations between environmental factors, particularly supportive social environments, and positive states of health. Identifying the pathways from protective social environments to reduced disease risk necessitates the use of animal models as a basis of explanation and a source of suggestions for further human research. We present two examples of this kind of cross-talk: (i) the possibility that the success of well-being therapy following pharmacological treatment for depression as a means of preventing recurrent depressive episodes is based on the stimulation of enrichment of dendritic networks in the hippocampus and spine retraction in the basolateral amygdala; (ii) the possibility that the release of intracerebral oxytocin is a mediating factor between persistently supportive social environments and reduced disease in later life, as exemplified by low levels of allostatic load.