Relationship Between Anxiety, Stress, Resilience and Brain Plasticity

Resilience and vulnerability do not necessarily represent opposite processes. Resilience is the capability to recover from adversity, while vulnerability is a tendency toward developing a maladaptive response to threatening situations. Both processes share forebrain structures and their connections with subcortical structures. The proper functioning of these structures and connections leads to the successful selection of strategies to cope with adverse situations, resulting in a useful adaptive form of anxiety. Brain structures involved in both processes include the prefrontal cortex, anterior cingulate, and insula, as well as the amygdala, hippocampus, nucleus accumbens, and ventral tegmental area, among others. Both processes are based on the plasticity of neuronal tissue, which arises from interactions between neurons, glial elements, neurotrophic factors, and an adequate balance of glutamate/γ-aminobutyric acid activity. Interactions among these factors give rise to the elimination of useless strategies or the acquisition of new strategies that allow recovery from the previous state or even a step forward in acquiring new strategies to face different environmental threats. This chapter reviews the ways in which the brain can develop adaptive anxiety and, consequently, resilience, but also vulnerability and, consequently, the development of anxiety disorders.