Task difficulty modulates young-old differences in network expression.

Journal Article (Journal Article)

The extent of task-related fMRI activation can vary as a function of task difficulty. Also the efficiency or capacity of the brain networks underlying task performance can change with aging. We asked whether the expression of a network underlying task performance would differ as a function of task demand in old and young individuals. 26 younger and 23 older healthy adults performed a delayed item recognition task that used the response signal method to parametrically manipulate the extrinsic difficulty of the task by imposing five different deadlines for recognition response. Both age groups showed a speed-accuracy trade-off, but the younger group achieved greater discriminability at the longer deadlines. We identified a spatial pattern of fMRI activation during the probe phase whose expression increased as the response deadline shortened and the task became more difficult. This pattern was expressed to a greater degree by the old group at the long deadlines, when the task was easiest. By contrast, this pattern was expressed to a greater degree by the younger group at the short deadlines, when the task was hardest. This suggests reduced efficiency and capacity of this network in older subjects. These findings suggest that neuroimaging studies comparing task-related activation across groups with different cognitive abilities must be interpreted in light of the relative difficulty of the task for each group.

Full Text

Duke Authors

Cited Authors

  • Stern, Y; Rakitin, BC; Habeck, C; Gazes, Y; Steffener, J; Kumar, A; Reuben, A

Published Date

  • January 2012

Published In

Volume / Issue

  • 1435 /

Start / End Page

  • 130 - 145

PubMed ID

  • 22197699

Pubmed Central ID

  • PMC3406734

Electronic International Standard Serial Number (EISSN)

  • 1872-6240

International Standard Serial Number (ISSN)

  • 0006-8993

Digital Object Identifier (DOI)

  • 10.1016/j.brainres.2011.11.061


  • eng