Meta-analyses of the n-back working memory task: fMRI evidence of age-related changes in prefrontal cortex involvement across the adult lifespan

Neuroimage. 2019 Aug 1;196:16-31. doi: 10.1016/j.neuroimage.2019.03.074. Epub 2019 Apr 4.

Abstract

Working memory, a fundamental cognitive function that is highly dependent on the integrity of the prefrontal cortex, is known to show age-related decline across the typical healthy adult lifespan. Moreover, we know from work in neurophysiology that the prefrontal cortex is disproportionately susceptibly to the pathological effects of aging. The n-back task is arguably the most ubiquitous cognitive task for investigating working memory performance. Many functional magnetic resonance imaging (fMRI) studies examine brain regions engaged during performance of the n-back task in adults. The current meta-analyses are the first to examine concordance and age-related changes across the healthy adult lifespan in brain areas engaged when performing the n-back task. We compile data from eligible fMRI articles that report stereotaxic coordinates of brain activity from healthy adults in three age-groups: young (23.57 ± 5.63 years), middle-aged (38.13 ± 5.63 years) and older (66.86 ± 5.70 years) adults. Findings show that the three groups share concordance in the engagement of parietal and cingulate cortices, which have been consistently identified as core areas involved in working memory; as well as the insula, claustrum, and cerebellum, which have not been highlighted as areas involved in working memory. Critically, prefrontal cortex engagement is concordant for young, to a lesser degree for middle-aged adults, and absent in older adults, suggesting a gradual linear decline in concordance of prefrontal cortex engagement. Our results provide important new knowledge for improving methodology and theories of cognition across the lifespan.

Publication types

  • Meta-Analysis
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Brain / physiology
  • Brain Mapping
  • Female
  • Humans
  • Longevity*
  • Magnetic Resonance Imaging
  • Male
  • Memory, Short-Term / physiology*
  • Middle Aged
  • Neuropsychological Tests
  • Prefrontal Cortex / physiology*
  • Reaction Time
  • Young Adult