Embers of change in cognition and brain function linger in the wake of a wildfire

Overview: People exposed to the California campfire in 2018 showed significant brain and cognitive function changes many months after the event. Findings add to the growing body of evidence supporting a growing phenomenon known as “climate trauma.”

Source: UCSD

In November 2018, the campfire burned a total of 239 square miles, destroyed 18,804 buildings and killed 85 people, making it the deadliest and most destructive wildfire in California history.

Three years later, researchers at the University of California San Diego published a new study that looked at the psychological consequences, finding that exposure to “climate trauma” for affected residents resulted in increased and chronic mental health problems, such as post-traumatic stress disorder. and depression.

In a new study, published in the Jan. 18, 2023 online issue of PLOS climatesenior author Jyoti Mishra, PhD, associate professor in the Department of Psychiatry at UC San Diego School of Medicine, director of the Neural Engineering and Translation Labs at UC San Diego, and associate director of the UC Climate and Mental Health Initiative, elaborated with her colleagues.

The research team reported that in a subgroup of individuals exposed to the campfire, significant differences in cognitive functioning and underlying brain activity were revealed using electroencephalography (EEG).

In particular, the researchers found that fire-exposed individuals showed increased activity in the brain regions involved in cognitive control and interference processing — the ability to mentally cope with unwanted and often distressing thoughts.

“To function properly on a day-to-day basis, our brains need to process information and manage memories in a way that helps achieve goals while ignoring or omitting irrelevant or harmful distractions,” says Mishra.

“Climate change is a new challenge. It is already well documented that extreme climate events have significant psychological consequences. For example, warming temperatures have even been linked to higher suicide rates. As the planet warms, more wildfires are expected in California and worldwide, with significant impacts on mental health.

“In this study, we wanted to learn if and how climate trauma affected and changed cognitive and brain functions in a group of people who experienced it at the campfire. We found that those who were directly or indirectly affected showed weaker interference processing. Such impaired cognitive performance can then impair daily functioning and reduce well-being.”

This shows a building and a car on fire during the 2018 campfire fire
The 2018 Camp Fire wildfire burned a total of 239 square miles, destroyed 18,804 buildings and killed 85 people. Researchers say it also caused lingering brain trauma in some of those exposed to the deadliest and most destructive wildfire in California history. Credit: National Institute of Standards and Technology

The study sample included 27 individuals who were directly exposed to the campfire (for example, their homes were destroyed), 21 who were indirectly exposed (they witnessed the fire but were not directly affected), and 27 control subjects. All participants underwent cognitive testing with synchronized EEG brain recordings.

Sixty-seven percent of those directly exposed to fire reported recent psychological trauma, as did 14 percent of those indirectly exposed. None of the control subjects reported recent exposure to trauma.

The EEG recordings showed that the brains of the individuals who reported trauma worked harder on interference processing and cognitive control, suggesting compensatory effort, but at a price: possibly an increased risk of neurological dysfunction elsewhere.

“The evidence of impaired interference processing, along with altered functional brain responses, is useful because it can help develop intervention strategies for resilience,” said Mishra.

“As the planet warms, more and more individuals will experience extreme climate exposures, such as wildfires, and having therapeutic tools that can address underlying neurocognitive issues will be an important complement to other social-behavioural therapies.”

Co-authors are: Gillian K. Grennan of UC San Diego; Mathew C. Withers, California State University at Chico; and Dhakshin S. Ramanathan, UC San Diego and VA San Diego Medical Center.

About this environmental neuroscience research news

Writer: Scott LaFee
Source: UCSD
Contact: Scott LaFee–UCSD
Image: The image is credited to the National Institute of Standards and Technology

Original research: Open access.
“Differences in interference processing and frontal brain function with climate trauma from California’s deadliest wildfire” by Jyoti Mishra et al. PLOS climate

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Abstract

Differences in interference processing and frontal brain function with climate trauma from California’s deadliest wildfire

As climate change accelerates extreme weather disasters, the mental health of affected communities is an increasing concern. In a recent study of 725 Californians, we showed that individuals directly exposed to California’s deadliest wildfire, the 2018 campfire, had significantly greater chronic symptoms of post-traumatic stress disorder, anxiety, and depression than control subjects not exposed to the fires.

Here we study a subsample of these individuals: directly exposed (n = 27), indirectly exposed (who witnessed the fire but were not directly affected, n = 21), versus unexposed controls of the same age and sex (n = 27). ).

All participants underwent cognitive testing with synchronized electroencephalography (EEG) brain recordings. In our sample, 67% of subjects directly exposed to fire reported recent trauma, while 14% of indirectly exposed subjects and 0% of unexposed control subjects reported recent trauma exposure.

Subjects exposed to fire showed significant cognitive impairment, particularly on the interference processing task and greater stimulus-evoked fronto-parietal activity as measured on this task.

In all subjects, we found that stimulus-evoked activity in the left frontal cortex was associated with an overall improved interference processing efficiency, suggesting that the increased activity observed in fire-exposed subjects may be a compensatory increase in cortical processes associated with cognitive control. can reflect.

To our knowledge, this is the first study to examine the cognitive and underlying neural effects of recent climate trauma.

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