The Hippocampus Is Coupled with the Default Network during Memory Retrieval but Not during Memory Encoding

Willem Huijbers*, Cyriel M. A. Pennartz, Roberto Cabeza, Sander M. Daselaar

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

87 Citations (Scopus)

Abstract

The brain's default mode network (DMN) is activated during internally-oriented tasks and shows strong coherence in spontaneous rest activity. Despite a surge of recent interest, the functional role of the DMN remains poorly understood. Interestingly, the DMN activates during retrieval of past events but deactivates during encoding of novel events into memory. One hypothesis is that these opposing effects reflect a difference between attentional orienting towards internal events, such as retrieved memories, vs. external events, such as to-be-encoded stimuli. Another hypothesis is that hippocampal regions are coupled with the DMN during retrieval but decoupled from the DMN during encoding. The present fMRI study investigated these two hypotheses by combining a resting-state coherence analysis with a task that measured the encoding and retrieval of both internally-generated and externally-presented events. Results revealed that the main DMN regions were activated during retrieval but deactivated during encoding. Counter to the internal orienting hypothesis, this pattern was not modulated by whether memory events were internal or external. Consistent with the hippocampal coupling hypothesis, the hippocampus behaved like other DMN regions during retrieval but not during encoding. Taken together, our findings clarify the relationship between the DMN and the neural correlates of memory retrieval and encoding.

Original languageEnglish
Article number17463
Number of pages9
JournalPLoS ONE
Volume6
Issue number4
DOIs
Publication statusPublished - 11 Apr 2011
Externally publishedYes

Keywords

  • MILD COGNITIVE IMPAIRMENT
  • RESTING-STATE NETWORKS
  • EPISODIC MEMORY
  • FUNCTIONAL CONNECTIVITY
  • ALZHEIMERS-DISEASE
  • BRAIN
  • FMRI
  • ATTENTION
  • SYSTEM
  • CORTEX

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