title: A bivariate twin study of regional brain volumes and verbal and nonverbal intellectual skills during childhood and adolescence.
abstract: Twin studies indicate that both intelligence and brain structure are moderately to highly heritable. Recent bivariate studies of adult twins also suggest that intelligence and brain morphometry are influenced by shared genetic factors. The current study examines shared genetic and environmental factors between brain morphometry and intelligence in a sample of children and adolescents (twins, twin siblings, and singletons; n = 649, ages 4-19). To extend previous studies, brain morphometric data were parsed into subregions (lobar gray/white matter volumes, caudate nucleus, lateral ventricles) and intelligence into verbal and nonverbal skills (Wechsler Vocabulary and Block Design subtests). Phenotypic relationships between brain volumes and intelligence were small. Verbal skills shared unique environmental effects with gray matter volumes while nonverbal skills shared genetic effects with both global and regional gray and white matter. These results suggest that distinct mechanisms contribute to the small phenotypic relationships between brain volumes and verbal versus nonverbal intelligence.
authors.affiliation: Child Psychiatry Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, 20892-1600, USA. gregwallace@mail.nih.gov
authors.forename: Gregory L
authors.initials: GL
authors.lastname: Wallace
authors.forename: Nancy Raitano
authors.initials: NR
authors.lastname: Lee
authors.forename: Elizabeth C
authors.initials: EC
authors.lastname: Prom-Wormley
authors.forename: Sarah E
authors.initials: SE
authors.lastname: Medland
authors.forename: Rhoshel K
authors.initials: RK
authors.lastname: Lenroot
authors.forename: Liv S
authors.initials: LS
authors.lastname: Clasen
authors.forename: James E
authors.initials: JE
authors.lastname: Schmitt
authors.forename: Michael C
authors.initials: MC
authors.lastname: Neale
authors.forename: Jay N
authors.initials: JN
authors.lastname: Giedd
mesh_terms: D000293:Adolescent; D000328:Adult; D001921:Brain / Q000033:anatomy & histology* / Q000502:physiology; D001931:Brain Mapping / Q000379:methods; D002648:Child; D002675:Child, Preschool; D003071:Cognition; D005260:Female; D006801:Humans; D007360:Intelligence; D007802:Language; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D014705:Verbal Behavior; D014785:Vision, Ocular