An analysis of the Adolescent Brain Cognitive Development study data showed that children accepted by their parents and more resilient to trauma tend to have an accelerated pace of cortical thinning, an indicator of brain development. In contrast, children exposed to household abuse tended to show slower microstructural development of the brain. The paper was published in Psychological Medicine.
As children grow, the cerebral cortex undergoes major structural and physiological changes that support increasingly complex thinking and behavior. In early childhood**,** the brain produces a very large number of synaptic connections between neurons, a process known as synaptogenesis. This overproduction makes the young brain highly plastic and responsive to environmental experiences and learning.
As development progresses, many of these connections are gradually removed through synaptic pruning, strengthening frequently used neural pathways while eliminating less efficient ones. One visible consequence of this process is cortical thinning, where the thickness of the gray matter in the cortex decreases as redundant synapses are pruned and neural circuits become more efficient.
At the same time, axons become increasingly wrapped in myelin, a fatty insulating layer that speeds up communication between brain regions. While increasing myelination is heavily associated with the volume of white matter in the brain, this insulating process also occurs within the gray matter, altering its microstructure as children and adolescents develop.
Different cortical regions mature at different rates, with sensory and motor areas developing earlier than regions responsible for higher cognitive functions. The prefrontal cortex, which supports planning, impulse control, and decision-making, develops particularly slowly and continues maturing into early adulthood.
Study author Anders Lillevik Thorsen and his colleagues investigated whether experiencing early life adversity influences brain development during adolescence. More specifically, they investigated whether cortical thickness, volumes of subcortical structures, cortical surface area, and microstructural properties of the brain tissue (T1w/T2w ratio) are associated with early life adversity experiences.
Early life adversity involves experiencing trauma, deprivation, and threats during childhood and adolescence. Study authors hypothesized that children exposed to household abuse would show faster maturation of their brains.
They analyzed data from the Adolescent Brain Cognitive Development (ABCD) study, a longitudinal study that follows participants from ages 9-11 to 19-21. This study investigates how the brain develops through this formative period and how biological and environmental factors impact the development of the brain. The study recruited participants from 21 sites across the U.S., largely through schools.
While the larger ABCD dataset includes nearly 12,000 children, the data used in this specific analysis came from 8,059 participants who had complete, high-quality magnetic resonance imaging (MRI) of their brains when they were 9-11 years of age.
For longitudinal analyses, researchers utilized follow-up MRI scans taken when 1,923 of these participants were 11-13 years old. The analyses also used data on participants’ experiences of early life adversity (as a combination of trauma exposure, family conflict / abuse**,** and emotional neglect), resilience to trauma, and socioeconomic status.
Results showed that, at ages 9-11, higher levels of parental acceptance, higher exposure to trauma, and being trauma resilient were associated with lower levels of cortical thickness**,** i.e., faster brain development. Children susceptible to trauma tended to have lower volumes of the hippocampus and a smaller cortical surface area.
Longitudinally, more parental acceptance reported at the start of the study was associated with more cortical thinning between ages 9-11 and 11-13, indicating a faster pace of brain development. On the other hand, more household abuse was associated with slower microstructural development of the brain (i.e., less change in the T1w/T2w ratio over time).
“Parental acceptance and trauma resilience are linked to accelerated pace of apparent cortical thinning in youth aged 9–13 years, while household abuse is associated with slower microstructural development, as reflected by smaller longitudinal changes in the T1w/T2w ratio,” study authors concluded.
The study contributes to the scientific understanding of the links between childhood experiences and brain development. However, it should be noted that the design of the study does not allow any causal inferences to be derived from the results.
The paper, “Associations between early life adversity and the development of gray matter macrostructure and microstructure,” was authored by Anders Lillevik Thorsen, Florence Friederike Boehmisch, Dag Alnæs, Andreas Dahl, Lars T. Westlye, and Olga Therese Ousdal.