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Intelligence is differentially related to cortical thickness and surface area

Wednesday, November 06, 2013 — Poster Session I

4:00 p.m. – 6:00 p.m.

FAES Academic Center (Upper-Level Terrace)




  • I.W. Eisenberg
  • B.A. Orionzi
  • A. Martin
  • G.L. Wallace


Background: Previous studies have shown intelligence (measured via IQ scores) is related to cortical brain volume. However, cortical volume conflates two measures, cortical thickness (CT) and pial surface area (SA), which have unique etiological underpinnings and therefore could be differentially related to IQ. Methods: 64 healthy males (age-mean, SD; 19.7, 3.5) provided a high-resolution 3-Tesla anatomic magnetic resonance image scan. IQ scores were collected using the Wechsler Abbreviated Scale of Intelligence (WASI). The FreeSurfer Image analysis suite was used to derive high-resolution CT and SA values at ~150,000 vertices per hemisphere. Results: Full scale IQ negatively correlated with CT in left superior frontal and positively correlated with SA bilaterally in parietal regions (cluster corrected ps < .05). Vocabulary and Matrix Reasoning (WASI subscales) were inversely related to CT in frontal and occipital areas (cluster corrected ps < .05). SA had more diffuse relationships, showing positive associations with Matrix Reasoning and Vocabulary, extending over bilateral frontal, temporal, and parietal cortices (cluster corrected ps < .05). Conclusions: Here we have shown that IQ scores are differentially related to CT and SA, both in directionality and location. Therefore relying on cortical brain volume may distort anatomical relationships with intelligence.

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