Brain & intelligence

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Readers of this weblog from back in 2002 know that we used to point to Paul Thompson’s research. So see this, Genetics of Brain Fiber Architecture and Intellectual Performance:

The study is the first to analyze genetic and environmental factors that affect brain fiber architecture and its genetic linkage with cognitive function. We assessed white matter integrity voxelwise using diffusion tensor imaging at high magnetic field (4 Tesla), in 92 identical and fraternal twins. White matter integrity, quantified using fractional anisotropy (FA), was used to fit structural equation models (SEM) at each point in the brain, generating three-dimensional maps of heritability. We visualized the anatomical profile of correlations between white matter integrity and full-scale, verbal, and performance intelligence quotients (FIQ, VIQ, and PIQ). White matter integrity (FA) was under strong genetic control and was highly heritable in bilateral frontal….bilateral parietal…and left occipital…lobes, and was correlated with FIQ and PIQ in the cingulum, optic radiations, superior fronto-occipital fasciculus, internal capsule, callosal isthmus, and the corona radiata…for PIQ, corrected for multiple comparisons). In a cross-trait mapping approach, common genetic factors mediated the correlation between IQ and white matter integrity, suggesting a common physiological mechanism for both, and common genetic determination. These genetic brain maps reveal heritable aspects of white matter integrity and should expedite the discovery of single-nucleotide polymorphisms affecting fiber connectivity and cognition.

Here’s the summary at ScienceDaily.

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  1. The image in the paper looks kind of crazy: 

  2. Interesting comment on the New Scientist site in relation to this study: 
    “Gould Is Turning In His Grave 
    Tue Mar 17 20:35:24 GMT 2009 by Jack Crane 
    As a scientist, I was outraged by Stephen J. Gould and other scientists particularly at Harvard that knew full well that a large portion of intelligence was inherited, but purposely misled the public by attacking IQ and other related work (e.g., Gould’s the Mismeasure of Man). As long ago as the 1980s, there was a clear correlation between the physical size of a brain (as measured carefully by NMR) and IQ. Twin studies were overwhelmingly clear that genetics was at least 50% responsible for our intelligence. I always felt that Gould, Lowenstein and others were the New Creationists. They refused to accept what science was discovering. They also used their power as scientists to attack evolutionary psychology which has become one of the new revolutionary fields in science. Even today in the university community in which I work, I find a large portion of the faculty (even scientists) horrified at any discussions involving intellectual inheritance or evolutionary psychology. One Dean told me once that “We have to save the children from this knowledge”. Kudos to New Scientist for reporting all the news. But don’t expect anyone inside the University Community to accept it.” 

  3. I can’t understand why no one is interested in commenting on this. This is the signature for the “major gene” for intelligence that Volkmar Weiss always said must exist. It does, and finding it will change everything.

  4. It doesn’t fit the narrative so it doesn’t exist. 
    We only see what we know. Johann Wolfgang von Goethe 
    The g Factor/Jensen covered this territory.

  5. I’m wondering, since the study shows that myelination leads to higher intelligence, can fish oils boost the amount of myelination?

  6. CalebZ, 
    Well if that’s the case, then a study of MS (Multiple Sclerosis) patients should tell us something, as they suffer from a decrease in myelination right? 
    If this decrease affects the brain in the same way it affects various nerve connections in the rest of the body, then that should be a valid test.