Under-recruitment and nonselective recruitment: dissociable neural mechanisms associated with aging

Neuron. 2002 Feb 28;33(5):827-40. doi: 10.1016/s0896-6273(02)00612-8.


Frontal contributions to cognitive decline in aging were explored using functional MRI. Frontal regions active in younger adults during self-initiated (intentional) memory encoding were under-recruited in older adults. Older adults showed less activity in anterior-ventral regions associated with controlled use of semantic information. Under-recruitment was reversed by requiring semantic elaboration suggesting it stemmed from difficulty in spontaneous recruitment of available frontal resources. In addition, older adults recruited multiple frontal regions in a nonselective manner for both verbal and nonverbal materials. Lack of selectivity was not reversed during semantically directed encoding even when under-recruitment was diminished. These findings suggest two separate forms of age-associated change in frontal cortex: under-recruitment and nonselective recruitment. The former is reversible and potentially amenable to cognitive training; the latter may reflect a less malleable change associated with cognitive decline in advanced aging.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aging / physiology*
  • Cognition / physiology
  • Female
  • Frontal Lobe / physiology*
  • Humans
  • Magnetic Resonance Imaging
  • Male
  • Memory / physiology*
  • Middle Aged
  • Neuropsychological Tests
  • Recruitment, Neurophysiological*
  • Time Factors
  • Verbal Behavior