Paul Thompson's Research Publications

GENETICS, BRAIN STRUCTURE, AND IQ

Proc. International Society for Intelligence Research, Newport Beach, CA, USA, Dec. 4-6, 2003.

Paul M. Thompson

UCLA School of Medicine, Los Angeles, CA


ABSTRACT


Brain imaging and genetic studies can reveal how nature and nurture impact human brain structure and intelligence. In the last decade, we and our collaborators have been compiling large databases of brain images (N>7000 subjects). This has helped to identify patterns of brain structure that are linked with cognitive performance, general intelligence (g), age, gender, individual genetic variations, and specific brain disorders (e.g., Alzheimer's disease and schizophrenia). We recently developed a large-scale computational brain atlas, including data components from the Finnish Twin registry, to store information on individual variations in brain structure and their heritability. We detected a genetic continuum in which brain structure is heavily genetically determined in some areas but not others [1,2]. Specifically, the quantity of gray matter in the frontal lobes of the brain was highly determined by heredity, and was linked with general intelligence (g).

Briefly, high-resolution MRI scans of the brain were acquired from 20 sets of twins (10 identical pairs, 10 fraternal). 3D brain maps were created revealing the amount of gray matter in different brain regions. Gray matter volume, in frontal brain regions, was more closely matched in the identical twins than in twins who were less similar genetically. Consequently, in these regions, the brain's structure is under strong genetic control [1]. Higher g scores were also found to be correlated with higher gray-matter volume in the brain's frontal lobes (p<0.0044), as well as with higher gray-matter volume overall (p<0.05). These findings are in line with many earlier studies linking g with MRI-based brain measures [3]. The association between regional brain volume and intelligence is also genetic in origin [4]. Intriguingly, this implies that the heritability of g is partly mediated by differences in brain structure that can be identified in a brain scan. Color-coded brain maps can also reveal the degree to which differences in our brain structure are attributable to individual genetic differences.

Population-based brain mapping studies are likely to engender a second revolution in linking genes, brain structure, and cognition. These studies can link individual variations, identified in brain images, with cognitive and genetic differences [5]. As such, they provide a means to explore the inheritance of personality differences and intellectual skills, and analyze the genetic transmission and dynamic spread of diseases that impact the human brain [6].

[1]. Thompson PM et al. (2001). Genetic Influences on Brain Structure, Nature Neuroscience, 4(2):1253-8.
[2]. Thompson PM et al. (2002). Mapping Genetic Influences on Human Brain Structure, Annals of Medicine, 34(7-8):523-536.
[3]. McDaniel MA, Nguyen NT (2002). A Meta-Analysis of the Relationship between MRI-Assessed Brain Volume and Intelligence, Proc. 2002 International Society for Intelligence Research (ISIR2002).
[4]. Posthuma D et al. (2002). The Association between Brain Volume and Intelligence is of Genetic Origin, Nature Neuroscience, 5(2):83-84.
[5]. Thompson PM, Toga AW (2002). A Framework for Computational Anatomy, Computing and Visualization in Science, 5:13-34.
[6]. Thompson PM et al. (2003). Dynamics of Gray Matter Loss in Alzheimer's Disease, J. Neuroscience, 23(3):994-1005.


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Contact Information

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    Paul Thompson, Ph.D.
    Assistant Professor of Neurology
    4238 Reed Neurology
    UCLA School of Medicine
    710 Westwood Plaza
    Westwood, Los Angeles CA 90095-1769, USA.

  • E-mail: thompson@loni.ucla.edu
  • Tel: (310)206-2101
  • Fax: (310)206-5518

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