Stability of whole brain and regional network topology within and between resting and cognitive states

PLoS One. 2013 Aug 5;8(8):e70275. doi: 10.1371/journal.pone.0070275. Print 2013.

Abstract

Background: Graph-theory based analyses of resting state functional Magnetic Resonance Imaging (fMRI) data have been used to map the network organization of the brain. While numerous analyses of resting state brain organization exist, many questions remain unexplored. The present study examines the stability of findings based on this approach over repeated resting state and working memory state sessions within the same individuals. This allows assessment of stability of network topology within the same state for both rest and working memory, and between rest and working memory as well.

Methodology/principal findings: fMRI scans were performed on five participants while at rest and while performing the 2-back working memory task five times each, with task state alternating while they were in the scanner. Voxel-based whole brain network analyses were performed on the resulting data along with analyses of functional connectivity in regions associated with resting state and working memory. Network topology was fairly stable across repeated sessions of the same task, but varied significantly between rest and working memory. In the whole brain analysis, local efficiency, Eloc, differed significantly between rest and working memory. Analyses of network statistics for the precuneus and dorsolateral prefrontal cortex revealed significant differences in degree as a function of task state for both regions and in local efficiency for the precuneus. Conversely, no significant differences were observed across repeated sessions of the same state.

Conclusions/significance: These findings suggest that network topology is fairly stable within individuals across time for the same state, but also fluid between states. Whole brain voxel-based network analyses may prove to be a valuable tool for exploring how functional connectivity changes in response to task demands.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Brain / anatomy & histology*
  • Brain / metabolism
  • Brain / physiology*
  • Cognition / physiology*
  • Female
  • Humans
  • Magnetic Resonance Imaging
  • Male
  • Rest / physiology*
  • Young Adult

Grant support

Internal institutional grants to the first and third author supported this research. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.