Vulnerability can be defined as the quality or state of being exposed to the possibility of being attacked or harmed, either physically or emotionally. In this chapter, it is defined as a possible ability of an individual or a group to face, manage, and anticipate a possible problem. This concept of vulnerability is associated with that of risk factor for social isolation, and therefore to situations that can also lead to illness and lack of mental and physical health. It can have its roots in poverty, in social exclusion, in ethnicity, in disability or simply in disease or specific developmental phases in life. All these aspects reflect very important vulnerability factors among biological, psychological, social, and behavioral variables. To date, no one has highlighted together two critical moments in life in which this brain area undergoes important variations: adolescence, in which its development occurs, and old age, in which this area goes into cognitive decline with the relative loss of many higher cognitive functions. This knowledge can help to better understand the forms of exclusion due to vulnerability in order to develop new forms of social inclusion.