Fig. 3: The stressed brain.

As an extrinsic factor capable of altering the brain, the concept of stress is based on nothing more than our bodily ability to perceive threats, real or imagined, actual or anticipated, emotional or physical. Such a realization is then accompanied by a sense of emotional inconvenience and extensive physiological changes that should, in principle, help us orchestrate the best adaptive behavior for survival, but which may actually lead to maladaptive behavioral adjustments. Indeed, a myriad of conditions can be perceived as stressful and the extent of brain effects may vary depending on the interplay between individual resilience and how long that stress lasts. Such effects include microstructural and subsequent macrofunctional changes, both of which are usually, but not only, coupled with the triggering of synaptic disconnections. Interestingly, stress-induced brain morphofunctional changes are generally recoverable. The effects of stress can overlap with the effects of neurodevelopment and aging on the brain, as we are all susceptible to stressors throughout our lives.