Although we’re always learning new things, our brains grow the most before age 6, when they’re about 90 percent the size of an adult brain. In an effort to learn more about the growing postnatal brain, a team of researchers have mapped the brains of infants during their first three months of life.
“A better understanding of when and how neurodevelopmental disorders arise in the postnatal period may help assist in therapeutic development,” said Dr. Dominic Holland, first author of the study published in JAMA Neurology. “Early intervention during a period of high neuroplasticity could mitigate severity of the disorders in later years.”
Up until now, most doctors used measuring tape to measure babies’ skull sizes, but by creating a template of the actual brain regions and their size, doctors will be better able to see when things start to go wrong. Studies have shown that neurodevelopmental disorders, such as depression, anxiety and ADHD can arise from poor brain development. The child may then go on to have difficulty socializing, succeeding in school, and working in the real world later on.
Holland and his colleagues found that the brain grew the quickest right after birth, at an average rate of one percent each day. By the end of the third month, it had slowed to a growing rate of 0.4 percent each day. When it came to specific parts of the brain, they found that the cerebellum, where movement is controlled, nearly doubled in size over the study period. It was also the fastest growing area of the brain. The slowest growing area was the hippocampus, which is responsible for memories.
The research also proved once again that babies born preterm are at a higher risk of illness. Those born a week early had a brain that was “four to five percent smaller than expected for a full-term baby,” Holland said. “The brains of premature babies actually grow faster than those of term-born babies, but that’s because they’re effectively younger — and younger means faster growth.” Still, he noted that preterm babies’ brains were two percent smaller at the end of the study term.
The study was performed using MRI brain scans, which 87 healthy babies were given during their first week of life. Some of them followed up with subsequent brain scans at the end of the first month, then again at the end of three months. The researchers said that if future studies analyze a larger group of babies, creating a reference point for neurodevelopmental disorders will be possible.