title: Brain size, sex, and the aging brain.
abstract: This study was conducted to examine the statistical influence of brain size on cortical, subcortical, and cerebellar compartmental volumes. This brain size influence was especially studied to delineate interactions with Sex and Age. Here, we studied 856 healthy subjects of which 533 are classified as young and 323 as old. Using an automated segmentation procedure cortical (gray and white matter [GM and WM] including the corpus callosum), cerebellar (GM and WM), and subcortical (thalamus, putamen, pallidum, caudatus, hippocampus, amygdala, and accumbens) volumes were measured and subjected to statistical analyses. These analyses revealed that brain size and age exert substantial statistical influences on nearly all compartmental volumes. Analyzing the raw compartmental volumes replicated the frequently reported Sex differences in compartmental volumes with men showing larger volumes. However, when statistically controlling for brain size Sex differences and Sex × Age interactions practically disappear. Thus, brain size is more important than Sex in explaining interindividual differences in compartmental volumes. The influence of brain size is discussed in the context of an allometric scaling of the compartmental volumes.
authors.affiliation: Division Neuropsychology, Institute of Psychology, University of Zurich, Switzerland; Center for Integrative Human Physiology, University of Zurich, Switzerland; International Normal Aging and Plasticity Imaging Center (INAPIC), University of Zurich, Switzerland; University Research Priority Program (URPP) "Dynamics of Healthy Aging", University of Zurich, Switzerland; Department of Special Education, King Abdulaziz University, Jeddah, Saudi Arabia.
authors.forename: Lutz
authors.initials: L
authors.lastname: Jäncke
authors.forename: Susan
authors.initials: S
authors.lastname: Mérillat
authors.forename: Franziskus
authors.initials: F
authors.lastname: Liem
authors.forename: Jürgen
authors.initials: J
authors.lastname: Hänggi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D000704:Analysis of Variance; D001921:Brain / Q000033:anatomy & histology* / Q000502:physiology*; D005260:Female; D007839:Functional Laterality; D066128:Gray Matter / Q000033:anatomy & histology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009929:Organ Size / Q000502:physiology; D012727:Sex Characteristics; D011795:Surveys and Questionnaires; D055815:Young Adult
keywords: brain size; magnetic resonance imaging; morphometry; neuroanatomy; sex differences