Analysis of research data on the cognitive development of the adolescent brain shows that children who are accepted by their parents and more resilient to trauma tend to have accelerated cortical thinning, a marker of brain development. In contrast, children exposed to domestic abuse tended to have slower brain microstructure development. The paper was published in psychiatry.
As children grow, the cerebral cortex undergoes significant structural and physiological changes to support increasingly complex thoughts and behaviors. During early childhood**,**, the brain generates a large number of synaptic connections between neurons. This is a process known as synaptogenesis. This overproduction makes young brains highly plastic and sensitive to environmental experiences and learning.
As development progresses, many of these connections are gradually removed by synaptic pruning, strengthening frequently used neural pathways while eliminating less efficient ones. One visible result of this process is cortical thinning, where redundant synapses are pruned and neural circuits become more efficient, reducing the thickness of the cortical gray matter.
At the same time, axons become increasingly encased in myelin, a fatty insulating layer that accelerates communication between brain regions. Although increased myelination is largely related to the amount of white matter in the brain, this insulating process also occurs within gray matter, whose microstructure changes as children and adolescents develop.
Different cortical areas mature at different rates, with sensory and motor areas developing faster than areas responsible for higher cognitive functions. The prefrontal cortex, which supports planning, impulse control, and decision-making, develops particularly slowly and continues to mature into early adulthood.
Study author Anders Lillewik Thorsen and colleagues investigated whether experiences of adversity early in life influence brain development during adolescence. More specifically, we investigated whether cortical thickness, volume of subcortical structures, cortical surface area, and microstructural properties of brain tissue (T1w/T2w ratio) are associated with early life adversity experiences.
Early life adversity includes experiencing trauma, deprivation, and threat during childhood and adolescence. The study authors hypothesized that children exposed to domestic abuse may have faster brain maturation.
They analyzed data from the Adolescent Brain Cognitive Development (ABCD) study, a longitudinal study that followed participants from ages 9 to 11 to 19 to 21. This research investigates how the brain develops throughout this formative period and how biological and environmental factors influence brain development. The study recruited participants from 21 facilities across the United States, primarily through schools.
While the larger ABCD dataset includes nearly 12,000 children, the data used in this particular analysis came from 8,059 participants who underwent complete high-quality magnetic resonance imaging (MRI) of their brains when they were 9 to 11 years old.
For the longitudinal analysis, the researchers used follow-up MRI scans taken when 1,923 of these participants were 11 to 13 years old. This analysis also used data on participants’ early life experiences of adversity (as a combination of exposure to trauma, family conflict/abuse**,**, and emotional neglect), resilience to trauma, and socioeconomic status.
The results showed that at ages 9 to 11, higher levels of parental acceptance, greater exposure to trauma, and greater resilience from trauma were associated with lower levels of cortical thickness and, therefore, earlier brain development. Children who are more susceptible to trauma tend to have smaller hippocampal volumes and smaller cortical surface areas.
Over time, researchers showed that the more parental acceptance reported at the start of the study, the thinner the cortex and faster the pace of brain development between ages 9 to 11 and 11 to 13. On the other hand, increased domestic abuse was associated with slower brain microstructural development (i.e., less change in the T1w/T2w ratio over time).
“Parental acceptance and resilience from trauma are associated with accelerated apparent cortical thinning in adolescents aged 9 to 13 years, whereas domestic abuse is associated with delayed microstructural development, as reflected by small longitudinal changes in the T1w/T2w ratio,” the study authors concluded.
This study contributes to the scientific understanding of the link between early childhood experiences and brain development. Note, however, that the study design did not allow for causal inferences from the results.
The paper “The association between early life adversity and the development of gray matter macro- and microstructure” was authored by Anders Lillevik Thorsen, Florence Friederike Boehmisch, Dag Alnæs, Andreas Dahl, Lars T. Westlye, and Olga Therese Ousdal.
