Researchers have mapped the brain structures that affect general intelligence.

The discovery was made by a collaborative team of neuroscientists at the California Institute of Technology (Caltech), the University of Iowa, the University of Southern California (USC), and the Autonomous University of Madrid.

The early edition of the Proceedings of the National Academy of Sciences published the study which included Jan Gläscher, first author on the paper and a postdoctoral fellow at Caltech, and Ralph Adolphs, the Bren Professor of Psychology and Neuroscience and professor of biology.

The Caltech scientists teamed up with researchers at the University of Iowa and USC to examine a uniquely large data set of 241 brain-lesion patients who all had taken IQ tests. The researchers mapped the location of each patient''s lesion in their brains, and correlated that with each patient''s IQ score to produce a map of the brain regions that influence intelligence.

Adolphs says," General intelligence, often referred to as Spearman''s g-factor, has been a highly contentious concept. But the basic idea underlying it is undisputed: on average, people''s scores across many different kinds of tests are correlated. Some people just get generally high scores, whereas others get generally low scores. So it is an obvious next question to ask whether such a general ability might depend on specific brain regions."

The researchers found that, rather than residing in a single structure, general intelligence is determined by a network of regions across both sides of the brain.

Adolphs further adds," It might have turned out that general intelligence doesn''t depend on specific brain areas at all, and just has to do with how the whole brain functions." (With Input from Agencies)