Early life stress combined with traumatic brain injury (TBI) could negatively impact behavior in adulthood, according to study researchers who presented new research at the Society’s annual meeting for Neuroscience, Neuroscience 2023. Early life stress and TBI were both associated. with abnormal social behavior and oxytocin signaling, explained the study’s first author, Michaela Breach.
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“Stress is really powerful, and we shouldn’t underestimate the impact of early-life stress on brain development,” said Kathryn Lenz, lead author of the study and associate professor of psychology at the Ohio State University, in the press release. “I think this question tends to get dismissed, but it is an incredibly important public health topic.”
Many children experience adverse childhood experiences (ACEs) that cause stress, which can increase the risk of illness and mental illness as they grow up. Additionally, children are prone to head injuries (often caused by falls) and studies suggest that these early injuries can cause mood disorders and social problems later in life.
However, little is known about how ACEs interact with early-life head trauma to cause behavioral or mental health problems. So researchers at Ohio State University conducted an animal study to understand whether early-life stress can worsen the effects of early-life head trauma. head injury on a patient’s health and behavior later in life.
“Using an animal model allows us to really understand the mechanisms by which these two elements might impact brain development as it occurs,” Lenz said in the press release. .
During the study, some newborn rats were separated from their mothers for 14 days (stressed), and others were not (non-stressed). On day 15, some rats in both cohorts suffered concussion-like head trauma under anesthesia; others suffered no head trauma. As a result, the rats suffered either stress only, head injuries only, or stress and head injuries. These rats were then compared to uninjured, non-stressed rats.
The investigators also used mononuclear RNA sequencing to see how gene expression in the hippocampal region of the brain was affected as the rats grew. The researcher observed that early life stress, alone and stress combined with head trauma, activated excitatory and inhibitory neural pathways; these are linked to brain plasticity (the adaptability of the brain to changes (good and bad)).
“This may suggest that the brain is opening to a new period of vulnerability or actively changing during this period where it could be programming deficits later in life,” Breach said in the press release.
Additionally, the results showed that stress and TBI activated the oxytocin pathway – oxytocin being a hormone associated with social bonding – while TBI alone inhibited it.
“These different effects with oxytocin signaling… demonstrate that the effect of stress could modulate how TBI changes the brain since the combined treatment was different from TBI itself,” Breach said in the Press release.
Additionally, early life stress alone also increased the likelihood that rodents would participate in risky behaviors (e.g., walking in open space); This is linked to human data that demonstrates that early-life stress can increase the risk of ADHD, “characterized by risky behaviors or substance use disorders,” Breach said. Thus, according to Lenz, it is important to combat stress early in life, with social support and enrichment being possible tools.
“I don’t think it can be overstated how damaging early life stressors can be if left untreated,” Lenz said.
Reference
Early life stress changes more genes in the brain than head trauma. Ohio State University. Press release. November 12, 2023. Accessed November 14, 2023. https://www.eurekalert.org/news-releases/1007591
