Genes and Brain Size

Researchers working with the ENIGMA project reportedly have uncovered specific genes that are linked to both brain volume and IQ (Intelligence Quotient). Lead researcher Paul Thompson, a neurologist at the University of California, Los Angeles, School of Medicine, said they found fairly unequivocal proof supporting a genetic link to brain function and intelligence. Many factors impact intelligence (e.g., number of connections between neurons, an individual’s personal experiences) and brain size may be one of them, although Thompson pointed out that brain size is not 100 percent correlated with a person's intelligence. Einstein reportedly had a smaller than average brain but the number of connections between neurons was much greater than in the average brain. Decreased brain volume is seen, however, in disorders such as Alzheimer's disease, depression, and schizophrenia (reported in the journal Nature Genetics).