What’s New in Psychology?
Effects of Stress on the Adolescent Brain
Jim Windell
Adolescence is known to be a time of dramatic changes. Not only in physical growth but in brain development as well.
For instance, there are important changes in hypothalamic-pituitary-adrenal (HPA) axis reactivity – which results in heightened stress-induced hormonal responses. At present, we don’t know what mediates these changes in stress reactivity. Nor do we understand the impacts they may have on an adolescent individual.
Since the teenage years is also a significant period of continued neural maturation, specifically within stress-sensitive limbic and cortical regions, it is possible that prolonged or repeated exposure to stress may result in maladaptive neurobehavioral development. However, the physiological and psychological implications of stress on the adolescent brain are far from clear, there are stress-related dysfunctions that occur during these years.
What does seem fairly certain is that stress and trauma during adolescence can lead to long-term health consequences, such as psychiatric disorders, which may arise from neurodevelopmental effects on brain circuitry.
A new study, recently published in Biological Psychiatry: Cognitive Neuroscience and Neuroimaging, has used functional magnetic resonance imaging (fMRI) to examine the effects of acute stress and “polyvicitimization” – repeated traumas – on three brain networks in adolescents. These three networks, sometimes referred to as “triple networks,” are the default mode network, the salience network, and the central executive network. The triple networks are critical for controlling cognition, emotion, perception, and social interaction. Abnormal activity in and between the three networks has been found to be associated with psychiatric symptoms.
The researchers analyzed functional connectivity (FC) data previously collected from 79 youth, ages 9 to 16, many with polyvictimization. To measure the effects of acute stress on brain connectivity, participants completed a task while undergoing fMRI scanning. In the control condition, subjects completed math problems at their own pace and were told their answers were not recorded; in the stress condition, participants had to do the math problems quickly during an allotted time and were given negative feedback about their performance throughout the test.
During the acute stress condition, participants showed altered functional connectivity between the three brain networks. Specifically, the researchers saw increased FC between the default mode and central executive networks, and decreased FC between the salience network and the other two networks. The authors postulate that the insula, a brain region associated with inwardly directed attention, could mediate the changes they saw in FC.
According to Dr. Rachel Corr, “While negative health outcomes have been associated separately with early life victimization exposure, disrupted adolescent neurodevelopment, and aberrant neural network responses to acute stress, no previous research had examined how these factors are related to each other.”
Corr, on the faculty at the University of North Carolina at Chapel Hill, and lead author of the study, explained that she and her colleagues aimed to put together these pieces of the puzzle.
The study found that those youth who experienced polyvictimization were more likely to show greater reductions in FC between the salience and default mode networks and the insula in particular. Altogether, the findings suggest that the brain may have adapted to repeated traumas to make it less able to react to stressful experiences. However, the researchers conclude that a better understanding of the neurodevelopmental effects of trauma on the brain will help researchers to better address the resulting psychiatric outcomes.
Cameron Carter, M.D., Editor of Biological Psychiatry: Cognitive Neuroscience and Neuroimaging, said of the work that it shows how repeated trauma may lead to a maladaptive response to acute stress in important functional brain networks. He added that ,”It reveals a potential mechanism by which multiple early life stressors may lead to increased neural vulnerability to stress and the associated liability to future mental health problems.”
To read the original article, find it with this reference:
Rachel Corr, Sarah Glier, Joshua Bizzell, Andrea Pelletier-Baldelli, Alana Campbell, Candace Killian-Farrell & Aysenil Belger. (2022). Triple Network Functional Connectivity During Acute Stress in Adolescents and the Influence of Polyvictimization. Biological Psychiatry: Cognitive Neuroscience and Neuroimaging. https://doi.org/10.1016/j.bpsc.2022.03.003.