Deconstructing the default: Cortical subdivision of the default mode/intrinsic system during self-related processing

Roy Salomon, Dana Rubi Levy, Rafael Malach

Research output: Contribution to journalArticlepeer-review

Abstract

Recent brain imaging research has highlighted a new global system of areas termed the Default Mode network (DM), which appears to specialize in intrinsically oriented functions. However, it is still unresolved to what extent this system contains functional subsystems as in the better known sensory and motor cortices. Here, we report that functional subdivisions can be revealed within individual nodes of the DM, such as the Inferior Parietal Lobule (IPL), through the use of different categories of self-oriented tasks. Subjects underwent BOLD fMRI scans during which they were asked to recall self-related positive and negative information in the categories of people and food. These tasks elicited distinct regions of activation within the DM. Importantly, the observed activations were above the activity level in the baseline, no-task condition for these regions. The main subdivision within the DM was observed in the inferior and posterior parietal cortex. Analysis of coherent resting state fluctuations (functional connectivity analysis) revealed that these regions of activation were part of a distinct network of regions within the DM. These results argue against viewing the DM as a unitary system, and are compatible with the notion that, similar to the rest of the cerebral cortex, the DM consists of distinct, functionally specialized subregions.

Original languageEnglish
Pages (from-to)1491-1502
Number of pages12
JournalHuman Brain Mapping
Volume35
Issue number4
DOIs
StatePublished - Apr 2014
Externally publishedYes

Keywords

  • Cortical specialization
  • FMRI
  • Functional connectivity
  • Rest
  • Self-referential processing

ASJC Scopus subject areas

  • Anatomy
  • Radiological and Ultrasound Technology
  • Radiology Nuclear Medicine and imaging
  • Neurology
  • Clinical Neurology

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