title: Impacts of normal aging on different working memory tasks: implications from an fMRI study.
abstract: OBJECTIVE
  To evaluate patterns of activation, convergence and divergence of three functional magnetic resonance imaging (fMRI) Working Memory (WM) tasks in two different age groups. We want to understand potential impact of task and subjects' age on WM activations as well as most important areas with regard to WM functions.
  
  
  METHODS
  Thirty-five healthy volunteers completed visual, verbal, and novel auditory WM tasks. The subjects were selected from age extremes to depict possible impact of normal aging. General Linear Model was used to report significant activations and the effect of group. One-to-one comparison of the tasks and Combined Task Analysis was also performed.
  
  
  RESULTS
  Most of the observed differences between the tasks were seen in areas that were responsible for feature processing. Frontal regions were mainstay activation areas, regardless of the utilized stimulus. We found an age-related reduction in activity of visual (in visually-presented tasks) and auditory (in auditory task) cortices but an age-related increase in prefrontal cortex for all tasks.
  
  
  CONCLUSIONS
  Regardless of the type of the task stimuli, frontal regions are the most important activation areas in WM processing. These areas are also main targets of age-related changes with regard to activation patterns. Our results also indicate that prefrontal overactivity in working memory might be a compensatory effort to mask age-related decline in sensory processing.
authors.affiliation: School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran NeuroImaging and Analysis Group, Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Fakhri
authors.forename: Hajir
authors.initials: H
authors.lastname: Sikaroodi
authors.forename: Farid
authors.initials: F
authors.lastname: Maleki
authors.forename: Hossein
authors.initials: H
authors.lastname: Ghanaati
authors.forename: Mohammad Ali
authors.initials: MA
authors.lastname: Oghabian
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology* / Q000523:psychology*; D001307:Auditory Perception / Q000502:physiology; D001931:Brain Mapping; D005260:Female; D005625:Frontal Lobe / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D008875:Middle Aged; D011597:Psychomotor Performance / Q000502:physiology; D014796:Visual Perception / Q000502:physiology