Research Shows Females' Brains More Efficient

June 20, 2005

Contact: Luke Frank, Senior Public Affairs Representative,505/272-3679


ALBUQUERQUE , NM As researchers at the University of New Mexico 's MIND Imaging Center probe deeper into the body's most mysterious organ the brain they are discovering new, very distinctive expressions of gender-specific neurological function.

E arly this year, the University of New Mexico (UNM) and the University of California , Irvine (UCI) concluded, in a joint research study detailed in the scientific journal NeuroImage, that men and women achieve similar IQs through fundamentally different regions and pathways in the brain.

Expanding on these data, UNM researchers now have discovered that a brain chemical found only in neurons N-acetylaspartate (NAA) can accurately predict performance on intelligence tests, a finding which will appear in the July issue of NeuroImage.

"This chemical, NAA, is very important to human neurological function and is much more predictive of IQ in women than in men," states Rex Jung, Ph.D., the study's lead author.

"Through various brain imaging techniques, such as structural and functional MRI (sMRI and fMRI), we're finding that male and female brains are modeled very differently," asserts Jung, an assistant research professor with UNM's Department of Neurology and research scientist at the MIND Imaging Center . "This likely impacts the way we think, the effects of disease, and the way in which we recover from injuries to the brain."

Previous research by this group demonstrated that men appear to have more gray-matter regions devoted to cognitive tasks, while women tend to have more white-matter regions devoted to similar tasks. Gray matter represents information processing centers in the brain, and white matter represents the networking of or connections between these processing centers.

"Now we have found that the brain's chemical environment is highly predictive of intelligence, particularly in women," he added . "These results may provide the chemical signature of why women are much more stable in terms of IQ, while men have much more variability in their IQ scores." For example, when assessing IQ scores, men as a group tend to fall more at the extremes both extremely bright and extremely dull while women's intelligence test scores tend to be clustered more around average levels of intelligence.

Moreover, this current research supports the notion that white matter is particularly important to intellectual functioning, and that, in women, both the amount and chemical components of their white matter is highly predictive of the individual score on tests of cognitive functioning.

"There are likely evolutionary components at play underlying brain organization between the sexes, as men are much more likely to suffer brain damage due to increased risk-taking and aggressive behavior than women," adds Jung. "It is possible that bigger brains and greater chemical variability (more redundancy) is necessary in men to accommodate the increased likelihood of suffering damage to the brain, while in women, a more efficient brain has evolved."

How these findings translate into different treatments for brain damage and disease based on gender remains to be determined. However, better understanding of the brain differences between the sexes is critical to this endeavor. In addition, identifying sensitivity to fluctuating chemistry in females' brains, particularly that of the chemical NAA, could lead to earlier diagnosis of onset of dementia and other neurological disorders. "Differences in intelligence processing are certainly interesting, but our research is focused on how these functional differences affect disease, treatment and recovery," Jung concludes.

For this study, UNM and the MIND Imaging Center combined their respective neuroimaging resources to study brain chemistry with Magnetic Resonance Spectroscopy (MRS). Jung designed the research protocol, conducted the MRI and MRS scanning, and performed cognitive testing on the subjects consisting of UNM undergraduate students.

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."

Currently, the MIND Imaging Center houses two MRI scanners from which structural, functional, and chemical 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 .

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