Cortex
Volume 46, Issue 4 , Pages 507-521, April 2010

The impact of increased relational encoding demands on frontal and hippocampal function in older adults

  • Eric D. Leshikar

      Affiliations

    • Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, IL, USA
    • ,
  • Angela H. Gutchess

      Affiliations

    • Department of Psychology, Brandeis University and Massachusetts General Hospital, Cambridge, MA, USA
    • ,
  • Andrew C. Hebrank

      Affiliations

    • Center for Brain Health and University of Texas at Dallas, TX, USA
    • ,
  • Bradley P. Sutton

      Affiliations

    • Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, IL, USA
    • Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA
    • ,
  • Denise C. Park

      Affiliations

    • Center for Brain Health and University of Texas at Dallas, TX, USA
    • Corresponding Author InformationCorresponding author. Center for Brain Health, The University of Texas at Dallas, 2200 West Mockingbird Lane, Dallas, Texas 75235, USA.

Received 9 November 2008; received in revised form 27 March 2009 and 11 June 2009; accepted 27 July 2009. published online 27 August 2009.

Abstract 

In the present study, we manipulated the cognitive effort in an associative encoding task using functional magnetic resonance imaging (fMRI). Older and younger adults were presented with two objects that were either semantically related or unrelated, and were required to form a relationship between the items. Both groups self-reported greater difficulty in completing the unrelated associative encoding task providing independent evidence of the associative difficulty manipulation. On both the low and high difficulty tasks, older adults showed a typical pattern of increased right inferior frontal recruitment relative to younger adults. Of particular interest was the finding that both groups showed increased activation as task difficulty increased in the left inferior frontal gyrus and left hippocampus. Overall, the results suggest that the aging brain is characterized by greater prefrontal processing, but that as cognitive demand increases, the networks used by older and younger adults are the largely the same.

Keywords: Aging, Relational memory, Prefrontal cortex, Hippocampus, Encoding

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PII: S0010-9452(09)00225-1

doi:10.1016/j.cortex.2009.07.011

Cortex
Volume 46, Issue 4 , Pages 507-521, April 2010

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