New brain-imaging research says that on average, cortex is thicker in youth with Down Syndrome than in typically developing youth, even though the overall volume of the cortex is lower in those with Down Syndrome.
The thickness of the brain's cerebral cortex could be a key to find answers about intellectual development in youth with Down Syndrome.
The result may also provide new insights to why individuals with this genetic neurodevelopmental disorder are highly susceptible to early onset Alzheimer's Disease later in life.
The cerebral cortex is involved in many important aspects of brain function including sensory and cognitive processes.
"Volume is a gross measure that can mask differences between thickness and surface area in the cortex," said Nancy Raitano Lee, an assistant professor at Drexel University, US.
"We wanted to learn more about how the brain is different in Down Syndrome compared to typical development, so we measured surface area and thickness, which both contribute to cortical volume but are determined by different genetic factors," Lee added.
Down Syndrome is typically associated with physical growth delays and mild to moderate intellectual disability. The team performed structural magnetic resonance imaging (MRI) of the brains of children and youth to better understand aspects of brain development.
Then they compared MRI measurements from 31 youth with Down Syndrome and 45 typically developing peers.
The cortex's surface area was found to be lower in the youth with Down Syndrome. As the surface area is a component of the total volume, the latter was also lower in volume. Individuals with Down Syndrome are more likely to develop early-onset Alzheimer's disease than the general population.
The study appeared in the journal Cerebral Cortex