People who score high on intelligence tests also activate a distinct set of brain regions during demanding mental tasks, reports a study in the March issue of Nature Neuroscience. The results may help researchers to understand the neural basis of individual differences in cognitive ability.
The authors, at Washington University in St. Louis, and Harvard University, scanned normal people with functional magnetic resonance imaging (fMRI) during a demanding memory task. Activity in distinct prefrontal areas and selected regions elsewhere in the brain was positively correlated with a measure of general intelligence known as general fluid intelligence (which is related to the more familiar IQ). Interestingly, these correlations were apparent almost exclusively on trials that were especially difficult because the subjects had to avoid choosing a ‘lure’ stimulus that was close to the right answer. Because many of the brain regions that showed this selective activation are involved in the control of attention, the authors suggest that individual differences in fluid intelligence might depend in part on differences in neural systems involved in the control of attention. The study, which is impressive in part because it involved a relatively large number of participants, will help to constrain theories of the neural mechanisms underlying differences in general intelligence. Nevertheless, the identified brain regions are involved in many functions, and so the challenge ahead will be to understand how differential activity in these brain regions contributes to problem-solving ability. John Duncan of Cambridge University discusses the paper in an accompanying News and Views article. Author contact: Jeremy Gray or Todd Braver Department of Psychology Washington University St. Louis, MO USA Tel: +1 314 935 8631 E-mail: jgray@artsci.wustl.edu or tbraver@artsci.wustl.edu Also available online. (C) Nature Neuroscience press release.
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