title: Changes in thickness and surface area of the human cortex and their relationship with intelligence.
abstract: Changes in cortical thickness over time have been related to intelligence, but whether changes in cortical surface area are related to general cognitive functioning is unknown. We therefore examined the relationship between intelligence quotient (IQ) and changes in cortical thickness and surface over time in 504 healthy subjects. At 10 years of age, more intelligent children have a slightly thinner cortex than children with a lower IQ. This relationship becomes more pronounced with increasing age: with higher IQ, a faster thinning of the cortex is found over time. In the more intelligent young adults, this relationship reverses so that by the age of 42 a thicker cortex is associated with higher intelligence. In contrast, cortical surface is larger in more intelligent children at the age of 10. The cortical surface is still expanding, reaching its maximum area during adolescence. With higher IQ, cortical expansion is completed at a younger age; and once completed, surface area decreases at a higher rate. These findings suggest that intelligence may be more related to the magnitude and timing of changes in brain structure during development than to brain structure per se, and that the cortex is never completed but shows continuing intelligence-dependent development.
authors.affiliation: Rudolf Magnus Institute of Neuroscience, Brain Division, University Medical Centre Utrecht, 3584 CX Utrecht, The Netherlands.
authors.forename: Hugo G
authors.initials: HG
authors.lastname: Schnack
authors.affiliation: Rudolf Magnus Institute of Neuroscience, Brain Division, University Medical Centre Utrecht, 3584 CX Utrecht, The Netherlands.
authors.forename: Neeltje E M
authors.initials: NE
authors.lastname: van Haren
authors.affiliation: Rudolf Magnus Institute of Neuroscience, Brain Division, University Medical Centre Utrecht, 3584 CX Utrecht, The Netherlands.
authors.forename: Rachel M
authors.initials: RM
authors.lastname: Brouwer
authors.affiliation: McConnell Brain Imaging Centre, Montreal Neurological Institute, McGill University, Montreal, QC, Canada H3A 2B4 and.
authors.forename: Alan
authors.initials: A
authors.lastname: Evans
authors.affiliation: Rudolf Magnus Institute of Neuroscience, Brain Division, University Medical Centre Utrecht, 3584 CX Utrecht, The Netherlands.
authors.forename: Sarah
authors.initials: S
authors.lastname: Durston
authors.affiliation: Department of Biological Psychology, VU University Amsterdam, 1081 BT Amsterdam, The Netherlands.
authors.forename: Dorret I
authors.initials: DI
authors.lastname: Boomsma
authors.affiliation: Rudolf Magnus Institute of Neuroscience, Brain Division, University Medical Centre Utrecht, 3584 CX Utrecht, The Netherlands.
authors.forename: René S
authors.initials: RS
authors.lastname: Kahn
authors.affiliation: Rudolf Magnus Institute of Neuroscience, Brain Division, University Medical Centre Utrecht, 3584 CX Utrecht, The Netherlands.
authors.forename: Hilleke E
authors.initials: HE
authors.lastname: Hulshoff Pol
mesh_terms: D000293:Adolescent; D000328:Adult; D000375:Aging / Q000502:physiology; D002540:Cerebral Cortex / Q000033:anatomy & histology* / Q000502:physiology*; D002648:Child; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007360:Intelligence; D007361:Intelligence Tests; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012044:Regression Analysis; D055815:Young Adult
keywords: MRI; brain development; cortex; intelligence; plasticity