title: Healthy and pathological processes in adult development: new evidence from neuroimaging of the aging brain.
abstract: OBJECTIVE
  Recent research has revealed that the population of older adults is composed not only of individuals who are either healthy or have an age-related disease, most commonly Alzheimer's disease, but also individuals with mild cognitive impairment who are at-risk for or already in the prodromal stage of Alzheimer's disease. These variations in cognitive aging can be related to their neural bases via structural and functional neuroimaging methods.
  
  
  RESULTS
  Healthy aging appears to primarily affect a frontal-striatal system that undergirds executive control of cognition, while minimally affecting medial temporal lobe structures. Functional imaging studies suggest that enhanced prefrontal engagement may offer compensatory plasticity that minimizes age-related cognitive losses. Mild cognitive impairment appears to affect the entorhinal cortex in particular, with functional consequences in other brain regions. Alzheimer's disease is characterized by severe hippocampal injury, although early-stage Alzheimer's disease may relatively spare some cortical regions.
  
  
  CONCLUSIONS
  Advances in in-vivo imaging methods are providing the tools for identifying different trajectories of neurocognitive aging, and knowledge about these brain changes may promote opportunities for treatment.
authors.affiliation: Stanford University, Stanford, California, Cambridge, Massachusetts, USA. hedden@psych.stanford.edu
authors.forename: Trey
authors.initials: T
authors.lastname: Hedden
authors.forename: John D E
authors.initials: JD
authors.lastname: Gabrieli
mesh_terms: D000367:Age Factors; D000375:Aging / Q000473:pathology*; D000544:Alzheimer Disease / Q000473:pathology; D016229:Amyloid beta-Peptides / Q000378:metabolism; D001921:Brain / Q000473:pathology* / Q000503:physiopathology; D001931:Brain Mapping; D003952:Diagnostic Imaging / Q000379:methods*; D007839:Functional Laterality; D006803:Human Development / Q000502:physiology*; D006801:Humans; D007858:Learning / Q000502:physiology
chemical_list: D016229:Amyloid beta-Peptides