Male and Female "Intelligence" Differences Identified

January 20, 2005

Contact: Luke Frank, Senior Public Affairs Representative, 505/272-3679 or 505/907-9525 (cell)


ALBUQUERQUE, NM Women are from Venus and men are from Mars? Not exactly, but the University of New Mexico's MIND (Mental Illness and Neuroscience Discovery) Imaging Center recently discovered critically important neurological differences in the way men and women "think".

Technological advances in neuroimaging have enabled researchers to explore exactly where brain activity resides in males and females, and how it affects thinking and intelligence which ultimately could lead to vastly different treatment protocols for brain-injured men and women.

In a follow-up to a recent study that pinpointed very specific brain regions which correlate with intelligence, researchers at the University of New Mexico's (UNM) Health Sciences Center and the University of California, Irvine (UCI), conclude that men and women achieve similar IQ results through fundamentally different regions and pathways in the brain.

"What's apparent is that human evolution has created two different types of brains designed for equally intelligent behavior," offers UCI's Rich Haier, Ph.D., who led the collaborative study.

"General human intelligence appears to be related to specific brain regions that comprise a mere 5-6 percent of the brain's total gray-matter volume," offers Rex Jung, Ph.D., assistant research professor with UNM's Department of Neurology and co-author of the study. "However, we found significant differences in the volume of gray and white brain matter related to intelligence between males and females."

According to Jung, despite the scientifically established fact that males have an 8-10-percent larger cerebrum than females, comparisons show essentially no difference in general intelligence between the sexes. However, the study did show significant differences in brain regions where males and females manifest their intelligence, with women having more white matter and men more gray matter related to intellectual skill.

"In lay terms, men have approximately 6.5 times the active gray matter than women, and women have nearly 10 times the active white matter than men," Jung asserts. "Gray matter represents information processing centers in the brain, and white matter represents the networking of - or connections between - these processing centers.

"This may help to explain why men tend to excel in tasks requiring more local processing (like mathematics), while women tend to excel at integrating and assimilating information from distributed gray matter regions in the brain, as is required for language facility," Jung continues. "These two very different neurological pathways and activity centers, however, result in equivalent overall performance on broad measures of cognitive ability like those found on intelligence tests."

Regional differences in which brain volume correlates with intelligence also were observed. For example, 84 percent of gray-matter regions and 86 percent of white-matter regions in women were found in the brain's frontal lobes, compared to 45 percent and zero percent for males respectively. "Intelligence activity for females emerges from a smaller and more anterior region of the brain," adds Jung, "which is consistent with clinical findings that frontal brain injuries can be more destructive to cognitive performance in women than men.

"In addition, the regions in which women had more gray-matter volume related to intelligence included Broca's area, which is central to expressive language, while in men, Wernicke's area, responsible for receptive language, had more gray-matter volume related to intelligence," he continues.

"This research may help to better understand and treat individuals suffering a decline in their intellectual functioning - particularly dementia," continues Jung. "More importantly, this research data could lead to earlier diagnoses of brain disorders in males and females, as well as more effective and precise treatment protocols to address particular regions in the brain."

For this study, UNM and UC Irvine combined their respective neuroimaging technology and subject pools to study brain morphology with Magnetic Resonance Imaging (MRI). Jung helped design the research protocol, conducted the MRI scanning, and performed cognitive testing on UNM subjects.

Using a technique called Voxel Based Morphometry (VBM), UC Irvine researchers converted MRI pictures into structural brain "maps" that correlate brain tissue volume with IQ.

The MIND Institute, of which the MIND Imaging Center at UNM is an integral component, is a unique scientific consortium between the University of New Mexico, Harvard University, the University of Minnesota, Los Alamos National Laboratory and other leading research facilities. Its investigators are developing cutting-edge neuroimaging technologies, sharing their advances and pooling their resources with one another, making the whole greater than the sum of its parts.

Many different imaging techniques can be used to study the brain, such as structural magnetic resonance (sMR), functional magnetic resonance (fMR), magnetoencephalography (MEG), magnetic resonance spectroscopy (MRS), and optical imaging. The MIND Institute combines these multi-faceted tools from institutions across the country to create a "virtual" image of brain structure and function.

This integrative strategy sharing techniques and expertise across sites and combining multiple approaches to understanding the mind and brain positions them to apply answers to crucial questions about the mechanisms and treatment of mental illness and neurological disorders.

"Only by understanding normal brain functioning can we hope to unlock the secrets of diseases such as dementia, schizophrenia and the like," Jung asserts. "By determining particular brain regions that underlie intellectual functioning, we can better understand how disruptions within these regions can lead to brain dysfunction characteristic of numerous psychiatric and neurological disorders."

"As our life expectancy increases, more people will suffer from dementia," he concludes. "We need research focused on understanding the complex structure and functioning of our brain in order to combat these devastating brain diseases."

Currently, the MIND Imaging Center houses two MRI scanners from which structural (sMRI), functional (fMRI), and chemical (MRS) research of brain structure and activity can be undertaken. Recently, the MIND Imaging Center added a magnetoencephalography (MEG) machine, making it one of the most sophisticated neuroimaging centers in the world.

The University of New Mexico Health Sciences Center provides added value to health care through leadership in providing innovative, collaborative education; advancing frontiers of science through research critical to the future of health care; delivering health care services that are at the forefront of science; and facilitating partnerships with public and private biomedical and health enterprises. For more information on the UNM Health Sciences Center, visit .

Contact: Luke Frank, 272-3322

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