In the young brain, erasing trauma memories is a challenge

The amazing property of plasticity in our brains allows them to alter over the course of our lifetimes. The brain is mostly plastic in our early years, when it is still developing, as would be expected.

Unraveling Early-Life Trauma: Insights from Mouse Studies on Brain Plasticity

Throughout our lives, our brains can change due to a remarkable property called plasticity. Predictably, the brain is mostly plastic during the formative years of life, when it is still developing. One way this shows up is in the ability to pick up new languages, but it also means being more sensitive to stressful situations, which can leave a mark that gets worse with age. The latter effect is well supported by several studies, but the effects of early-life trauma exposure on the various types of brain cells and their interactions with one another in adulthood are poorly understood.

Chen’s lab at Weizmann’s Brain Sciences Department studies how the body responds to stress on a cellular and behavioural level. Chen’s group to explore the effects of stress during pregnancy on mature mouse pups in earlier investigations.

Scientists, under the direction of Dr. Aron Kos, examined the effects of early-life trauma on mouse pups in the present study. The researchers combined Chen’s lab’s capabilities to increase our grasp of this subject: its proficiency in investigating the chemical mechanisms of the brain at the highest resolution. Utilizing individual cell-level genetic sequencing; being able to track numerous behavioral traits using cameras in a complex social setting designed to mimic natural living circumstances; and being able to use machine learning and artificial intelligence techniques to handle the vast amounts of data produced in this setting.

According to this thorough behavioral mapping, mice that experienced postnatal trauma—in this example, being abandoned by their mothers—exhibited a range of behaviors that suggested they were at the bottom of the dominance hierarchy.

Unveiling Early Trauma’s Impact: Insights from Mouse Models and Brain Science

Our brains have an amazing property called plasticity, which allows them to evolve and adapt as we grow older. Because the brain is still developing in our early years, this flexibility is most noticeable, exhibiting increased plasticity. This stage promotes quick learning, including picking up a language, but it also makes the brain more vulnerable to painful experiences, creating long-lasting memories that could get stronger as people age. Numerous studies confirm the long-lasting impact of early trauma, but less is known about how specifically it affects different types of brain cells and how they communicate as adults.

The study, carried out in the lab of Dr. Chen in the Brain Sciences Department at Weizmann University, explores the behavioral and molecular aspects of stress response. The goal of earlier research was to determine how stress affects mature mouse offspring throughout pregnancy. In the most recent study, under the direction of Dr. Aron Kos, the researchers investigated the effects of trauma sustained soon after birth on the maturation of mouse pups. The study leveraged Chen’s lab’s expertise in genetic sequencing, behavioral tracking, and AI for comprehensive data analysis. These methods allowed researchers to examine molecular brain processes at a granular level.

Unveiling Trauma’s Lasting Impact: Insights from Mice and Human Behavior

Behavioral mapping showed adult mice stressed early, like by maternal neglect, displayed traits indicating a lower dominance position. Dr. Juan Pablo Lopez, a former postdoctoral researcher, emphasized the human counterparts of these behaviors. He mentioned characteristics that are frequent after trauma, such as excessive introversion, social anxiety, and an avoidant disposition.

Researchers simulated peer bullying in adult mice to study how early trauma affects the adult brain’s responses. Using single-cell RNA sequencing, researchers compared four adult mouse groups: no trauma, adult bullying, infancy trauma, and both.

Harnessing Brain Plasticity: Early Intervention and Trauma Recovery

The comparison showed early trauma uniquely affected gene expression in glutamatergic and GABAergic neuron subpopulations. This effect was most noticeable in mice that had experienced both adult bullying and trauma during infancy.

Brain cells communicate using excitatory or inhibitory signals, and a balance between them is crucial for proper function. Electrophysiological studies confirmed that early trauma led to an excitatory-inhibitory imbalance in the hippocampus.

Researchers attempted to correct the disruption by administering diazepam (Valium) shortly after the early shock. The treated mice notably reduced behavioral issues and improved their social status, countering expected negative effects.

The study emphasizes early intervention, leveraging the developing brain’s plasticity to counteract trauma’s negative impacts effectively. Researchers emphasized a tailored treatment approach and cautioned against indiscriminate medication use, though they acknowledged its potential.

Dr. Chen emphasizes the research’s broader implications for addressing persistent stress in regions affected by violence and displacement. Identifying a key brain process affected by childhood stress suggests using brain plasticity to mitigate long-term adult effects.