Exercise, Age-Related Memory Decline, And Hippocampal Function
Condition: Cognitive Deterioration; Disorder of Aging
Study type: Interventional

Summary: 
      The purpose of this study is to test the hypothesis that aerobic exercise leads increased
      cerebral blood volume in the dentate gyrus of the hippocampus in a sample of young and older
      adults.
    

Detailed description: 
      In the US, increased length of life and reduced morbidity and mortality have resulted in a
      growing number of older adults, the demographic "time bomb" often referred to in discussions
      of public policy. According to the Census Bureau, the population aged 65 and over will double
      in size within the next 25 years. Moreover, these older adults will live healthier lives than
      their predecessors. While this increased length of a healthy life is an undeniable societal
      benefit, it brings with it a major societal problem: an epidemic of aging-related cognitive
      decline. The need to develop interventions to address this growing problem is urgent.
      Aging-related cognitive dysfunction is not diffuse; rather it targets selected brain areas,
      in particular the frontal lobes and the hippocampal formation. The separate but
      interconnected subregions of the hippocampus are differentially vulnerable to pathogenic
      mechanisms, including the normal aging process. A range of in vivo and post-mortem studies
      have converged on the dentate gyrus (DG) as the hippocampal subregion differentially targeted
      by the aging process. As with pathogenic processes, any intervention that improves brain
      function does so with regional selectivity. One such intervention is physical exercise, which
      has been shown to improve both frontal lobe and hippocampal function. Using a high-resolution
      variant of functional magnetic resonance imaging (fMRI), the investigators have demonstrated
      that aerobic training selectively benefitted DG function both humans and mice. In addition,
      improvement in DG function was associated with improved performance on a word list learning
      task but not in tasks conventionally thought to be frontal lobe dependent. The human part of
      the study had significant shortcomings, however: it was small (N = 11), lacked a control
      group, enrolled only young subjects (age 20-45 years), and employed only a limited
      neuropsychological testing battery. The overall goal of this proposal is to use the
      high-resolution variant of fMRI to test the hypothesis that aerobic training will induce
      improvements in DG function in a sample of younger (age 20-35) and older (50-65) adults,
      assigned randomly to an active training condition or wait list control group. The
      investigators will use more comprehensive neuropsychological testing to examine the
      relationship between changes in DG function and selected cognitive capacities. Taken together
      with the observation that normal aging differentially targets the DG, this research program
      will establish that physical exercise is an effective approach for ameliorating the insidious
      cognitive slide that occurs in aging. Thus, the potential significance of this application is
      substantial.
    

Intervention name(s): aerobic training; Wait list
Intervention type(s): Behavioral; Behavioral
Intervention description(s): 12 weeks of aerobic training, 4X/week; wait list control condition
Other intervention name(s): Wait list control
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Outcomes Assessor)
Primary purpose: Basic Science
Keywords: cerebral blood volume; aging; exercise