title: Differential effect of age on posterior and anterior hippocampal functional connectivity.
abstract: Aging is associated with declines in cognitive performance and multiple changes in the brain, including reduced default mode functional connectivity (FC). However, conflicting results have been reported regarding age differences in FC between hippocampal and default mode regions. This discrepancy may stem from the variation in selection of hippocampal regions. We therefore examined the effect of age on resting state FC of anterior and posterior hippocampal regions in an adult life-span sample. Advanced age was associated with lower FC between the posterior hippocampus and three regions: the posterior cingulate cortex, medial prefrontal cortex, and lateral parietal cortex. In addition, age-related reductions of FC between the left and right posterior hippocampus, and bilaterally along the posterior to anterior hippocampal axis were noted. Age differences in medial prefrontal and inter-hemispheric FC significantly differed between anterior and posterior hippocampus. Older age was associated with lower performance in all cognitive domains, but we observed no associations between FC and cognitive performance after controlling for age. We observed a significant effect of gender and a linear effect of COMT val158met polymorphism on hippocampal FC. Females showed higher FC of anterior and posterior hippocampus and medial prefrontal cortex than males, and the dose of val allele was associated with lower posterior hippocampus - posterior cingulate FC, independent of age. Vascular and metabolic factors showed no significant effects on FC. These results suggest differential age-related reduction in the posterior hippocampal FC compared to the anterior hippocampus, and an age-independent effect of gender and COMT on hippocampal FC.
authors.affiliation: Institute of Gerontology and Department of Psychology, Wayne State University, Detroit, MI, USA. Electronic address: damoiseaux@wayne.edu.
authors.forename: Jessica S
authors.initials: JS
authors.lastname: Damoiseaux
authors.affiliation: Institute of Gerontology and Department of Psychology, Wayne State University, Detroit, MI, USA.
authors.forename: Raymond P
authors.initials: RP
authors.lastname: Viviano
authors.affiliation: School of Kinesiology, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Peng
authors.initials: P
authors.lastname: Yuan
authors.affiliation: Institute of Gerontology and Department of Psychology, Wayne State University, Detroit, MI, USA.
authors.forename: Naftali
authors.initials: N
authors.lastname: Raz
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D002318:Cardiovascular Diseases / Q000453:epidemiology / Q000503:physiopathology*; D002394:Catechol O-Methyltransferase / Q000235:genetics*; D002540:Cerebral Cortex / Q000503:physiopathology*; D015897:Comorbidity; D063132:Connectome / Q000706:statistics & numerical data; D005260:Female; D020022:Genetic Predisposition to Disease / Q000453:epidemiology / Q000235:genetics; D006624:Hippocampus / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008659:Metabolic Diseases / Q000453:epidemiology / Q000503:physiopathology*; D008824:Michigan / Q000453:epidemiology; D008875:Middle Aged; D009415:Nerve Net / Q000503:physiopathology; D009434:Neural Pathways / Q000503:physiopathology; D015995:Prevalence; D012307:Risk Factors; D017678:Sex Distribution; D012737:Sex Factors; D055815:Young Adult
chemical_list: C588010:COMT protein, human; D002394:Catechol O-Methyltransferase
keywords: Aging; COMT val158met; Functional connectivity; Gender; Hippocampus; Vascular risk