When a person is stressed, the brain is working overtime to process everything. It can be short-term stress like a car accident or a more chronic situation with ongoing stressors, but either way, there is only so much bandwidth in the brain and stress can impact other cognitive functions.
New research from scientists at the University of Innsbruck in Austria suggests that in any stressful or challenging experience, the energy your brain needs to manage it means that there is a deficit in understanding where you are and what is going on in your environment.
The research involved having volunteers watch video clips of specific events and experiences. Some of the clips contained a challenging situation that was negative, a challenging experience that was positive and a neutral clip with no particular stressors. After they viewed the clips, the participants were asked to take tests that measured the ability to acquire information about their surroundings and where or when particular actions would happen. This usually is an ability the brain has that goes unnoticed by most people; it happens unconsciously. As we navigate through an area or a task, the brain is processing the visual input, and remembering how to perform specific actions.
The clips were categorized by content. The negative clip included some violence. The positive clip was a romantic scene with some sexual content. The neutral video had no significant events in it. Previous research on trauma has shown that any memories formed as a result of a traumatic event usually lack any specific context or details about time and place. The only part of the memory is the trauma. The recent research showed that after viewing the negative and positive clips, the result was the same. The ability of the participants to understand where they were in time and space was lower. Without being able to fully recognize and navigate an environment, memory formation is disrupted.
The team at Innsbruck was led by researchers Thomas Maran, Pierre Sachse and Marco Furtner and their results point to an unexpected finding that even a positive experience, if challenging enough, can impact memory formation in the brain.
The tests that participants took after viewing the film clips were designed to measure "spatial and sequential context." After the romantic scene and the violent scene, participants were less able to remember where specific objects had been placed. Also, the ability to notice clear patterns in some of the tasks was also lower after watching the challenging scenes.
The study did not include any brain imaging, blood tests or other physical assessments, so it's hard to say why this disruption occurs, but it's likely related to how the hippocampus functions. Memories are formed in this region of the brain, and it's also the part of the brain that processes visual stimuli such as road signs, landmarks and the passage of time. Most of spatial and sequential context happens in the hippocampus, so moving forward the team hopes to look more closely at this area for a better understanding of stress, trauma, and memory. Maran summarized the work saying, "Changes in cognition during high arousal states play an important role in psychopathology." The video below has more information.