SAM: Memory contextualization in PTSD

Introduction

When individuals experience something, the surrounding environment significantly influences their memory of the event. We refer to the details of the environment as context. Information about this context is unconsciously linked to the event in memory, making memories context-dependent. The accuracy of this association is pivotal because the contextual cues determine whether someone remembers the event. Inaccurate linking of this information may lead to overly generalized memories, resulting in frequent or misplaced recollections. Such issues can particularly arise during traumatic events. Individuals with post-traumatic stress disorder (PTSD) are often reminded of these events, even in safe environments. It's plausible that inadequate storage of contextual information during the traumatic event leads to the memory becoming overly general.

Project overview

Objective:

To investigate why (unpleasant) memories become too general and the role of stress therein, the SAM project is initiated. Within this project, we examined the influence of stress on the context-dependent memory for neutral, emotional, and anxious information. Prior studies indicated that stress has immediate and delayed effects on memory. In the current study, we specifically focused on the role of stress on context-dependent memory. For this purpose, we examined three groups that differed in the timing of stress induction: long before the memory test, just before the memory test, or not at all.

Target population: 

Males (18-50 years) without any psychological complaints.

Timeframe: 

The study started in 2015 and was completed in 2019.

Results:

Stress affects the context-dependency of memories containing neutral information, and time plays an important role in this. The immediate effects of stress result in less context-dependent storage of this information in memory. As a result, the memories contain fewer environmental details and are thus more general. The delayed effects of stress had the exact opposite effect: information was stored with more context details. When experiencing a stressful event, the immediate and delayed effects occur sequentially. Our findings emphasize the importance of balancing these effects to ensure memories are neither overly generalized nor overly specific. This knowledge may contribute to a better understanding of the development of conditions such as PTSD in the future.

Publications

Sep MSC, van Ast VA, Gorter R, et al. Time-dependent effects of psychosocial stress on the contextualization of neutral memories. Psychoneuroendocrinology 2019; 108: 140–149. https://doi.org/10.1016/j.psyneuen.2019.06.021