Independent component model of the default-mode brain function: Assessing the impact of active thinking.

Full Abstract

The "default-mode" network is an ensemble of cortical regions, which are typically deactivated during demanding cognitive tasks in functional magnetic resonance imaging (fMRI) studies. Using functional connectivity, this network can be conceptualized and studied as a "stand-alone" function or system. Regardless of the task, independent component analysis (ICA) produces a picture of the "default-mode" function even when the subject is performing a simple sensori-motor task or just resting in the scanner. This has boosted the use of default-mode fMRI for non-invasive research in brain disorders. Here, we studied the effect of cognitive load modulation of fMRI responses on the ICA-based pictures of the default-mode function. In a standard graded working memory study based on the n-back task, we used group-level ICA to explore the variability of the default-mode network related to the engagement in the task, in 10 healthy volunteers. The analysis of the default-mode components highlighted similarities and differences in the layout under three different cognitive loads. We found a load-related general increase of deactivation in the cortical network. Nonetheless, a variable recruitment of the cingulate regions was evident, with greater extension of the anterior and lesser extension of the posterior clusters when switching from lower to higher working memory loads. A co-activation of the hippocampus was only found under no working memory load. As a generalization of our results, the variability of the default-mode pattern may link the default-mode system as a whole to cognition and may more directly support use of the ICA model for evaluating cognitive decline in brain disorders.

Learn Faster Today Improve your study skills

Author information

Author/s: Esposito, Fabrizio (F); Bertolino, Alessandro (A); Scarabino, Tommaso (T); Latorre, Valeria (V); Blasi, Giuseppe (G); Popolizio, Teresa (T); Tedeschi, Gioacchino (G); Cirillo, Sossio (S); Goebel, Rainer (R); Di Salle, Francesco (F);

Affiliation: Department of Neurological Sciences, University of Naples Federico II, II Policlinico (Nuovo Policlinico) Padiglione 17, Via S. Pansini 5, 80131 Naples, Italy. faesposi(-atsign-)unina.it

Journal and publication information

Publication Type: Comparative Study; Journal Article

Journal: Brain research bulletin (Brain Res Bull), published in United States. (Language: eng)

Reference: 2006-Oct; vol 70 (issue 4-6) : pp 263-9

Dates: Created 2006/10/09; Completed 2006/12/05;

PMID: 17027761, status: MEDLINE (last retrieval date: 12/26/2008)

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

External Links for this article (including full text providers, if available):

Click Electronic Full-text Provider Links to see options for finding the electronic full text links to this article. Note there may be a subscription or fee required for access to the full text. See our FAQ for information on finding FREE full text articles.

This article may also be located in paper journal collections available in many libraries. Use the Journal and Publication Information above to find the full article.

MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Adult
Brain - blood supply; physiology
Brain Mapping
Female
Humans
Image Processing, Computer-Assisted - methods
Magnetic Resonance Imaging - methods
Male

Male
Memory, Short-Term - physiology
Neural Networks (Computer)
Neuropsychological Tests - statistics & numerical data
Oxygen - blood
Principal Component Analysis
Thinking - physiology
Time Factors

Associated Chemicals: Oxygen (7782-44-7)

These are the highest related articles currently in the database:

See 100+ related articles.