Memories in context: On the role of cortisol

Memory can easily be reinstated by certain cues from the environment. Indeed, the ability to store memories into their original encoding context (i.e., memory contextualization) is highly adaptive as it can help to retrieve memories that are likely to be appropriate in a specific context, while at the same time preventing the retrieval of irrelevant or undesired memories in that context. Stress, and more specifically, cortisol, can generally alter memory processes by exerting effects on local memory circuitry in the brain. However, the exact mechanisms by which cortisol may alter the ability to integrate a central memory into its surrounding context remain unknown. With this thesis, Vanessa van Ast corroborated the notion that memories are highly context dependent. More importantly, with a series of experiments, she demonstrated that cortisol indeed plays an important role in binding memories, and depending on a range of closely described factors, this binding may sometimes be in context, and sometimes be out of context. These findings provide further clues on the etiology and treatment of stress-related pathology characterized by disturbances in memory contextualization, such as posttraumatic stress disorder.