WEDNESDAY, Feb. 12, 2014 (HealthDay News) — Scientists who discovered a gene that links the thickness of the brain’s gray matter to intelligence say their finding might help improve understanding of brain disorders such as autism and schizophrenia.
The team looked at the cerebral cortex, which is the outside layer of the human brain. It plays an important role in areas such as memory, attention, thought, language and consciousness. Previous research has shown that the thickness of the cerebral cortex is closely linked with intelligence.
Until now, no genes associated with the thickness of the cerebral cortex have been identified, the study authors said.
The researchers at King’s College London, in England, analyzed DNA samples and MRI brain scans from nearly 1,600 healthy 14-year-olds, who also underwent tests to determine their intelligence levels.
The scientists examined more than 54,000 variations of genes that might play a role in brain development. Teens with a particular variant of one gene (called the NPTN gene) had a thinner cortex on the left side of the brain and scored lower on the intelligence tests, according to the study.
The findings were published Feb. 11 in the journal Molecular Psychiatry.
This genetic variation is estimated to account for only about 0.5 percent of the total variation in intelligence. But the findings may prove important in learning more about the biological factors underlying conditions such as autism and schizophrenia, the researchers said.
“We wanted to find out how structural differences in the brain relate to differences in intellectual ability,” study lead author Dr. Sylvane Desrivieres said in a King’s College news release. “The genetic variation we identified is linked to synaptic plasticity — how neurons communicate.”
“This may help us understand what happens at a neuronal level in certain forms of intellectual impairments, where the ability of the neurons to communicate effectively is somehow compromised,” Desrivieres said.
“It’s important to point out that intelligence is influenced by many genetic and environmental factors,” she said. “The gene we identified only explains a tiny proportion of the differences in intellectual ability, so it’s by no means a ‘gene for intelligence.'”
The U.S. National Institute of Neurological Disorders and Stroke has more about the brain and how it works.