Chronic social stress‐induced functional and morphological alterations of neurons and their significance

Abstract

Patients with depression and rodents exposed to chronic stress exhibit functional and structural changes in diverse brain regions, including atrophy of the prefrontal cortex and hippocampus. Glucocorticoids, systemic inflammation and brain inflammation have been shown to cause region‐specific changes in molecular signaling in neurons and alter the activity dynamics of neural networks composed of stress‐related brain regions, resulting in depressive‐like behaviors. These neural activity dynamics are also altered by the accumulation of environmental factors, which contribute to the formation of vulnerability and resilience to stress. In this paper, I discuss the mechanisms of stress‐induced changes in neuronal function and morphology, and introduce an ultrastructural analysis of synapses using three‐dimensional electron microscopy which is useful for elucidating the effects of neuronal morphological changes on neural circuit networks. In the future, it will be important to focus on the functional and structural changes in each specific neural circuit due to the accumulation of stress and environmental factors to elucidate the mechanisms of stress pathology and vulnerability and resilience to stress.