Bottom-up sensory processing can induce negative BOLD responses and reduce functional connectivity in nodes of the default mode-like network in rats

Rukun Hinz, Lore M. Peeters, Disha Shah, Stephan Missault, Michaël Belloy, Verdi Vanreusel, Meriam Malekzadeh, Marleen Verhoye, Annemie Van der Linden, Georgios A. Keliris

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

The default mode network is a large-scale brain network that is active during rest and internally focused states and deactivates as well as desynchronizes during externally oriented (top-down) attention demanding cognitive tasks. However, it is not sufficiently understood if salient stimuli, able to trigger bottom-up attentional processes, could also result in similar reduction of activity and functional connectivity in the DMN. In this study, we investigated whether bottom-up sensory processing could influence the default mode-like network (DMLN) in rats. DMLN activity was examined using block-design visual functional magnetic resonance imaging (fMRI) while its synchronization was investigated by comparing functional connectivity during a resting versus a continuously stimulated brain state by unpredicted light flashes. We demonstrated that the BOLD response in DMLN regions was decreased during visual stimulus blocks and increased during blanks. Furthermore, decreased inter-network functional connectivity between the DMLN and visual networks as well as decreased intra-network functional connectivity within the DMLN was observed during the continuous visual stimulation. These results suggest that triggering of bottom-up attention mechanisms in sedated rats can lead to a cascade similar to top-down orienting of attention in humans and is able to deactivate and desynchronize the DMLN.

Original languageEnglish
Pages (from-to)167-176
Number of pages10
JournalNeuroImage
Volume197
DOIs
StatePublished - Aug 15 2019

Keywords

  • Default mode network
  • Functional connectivity
  • Rats
  • Resting-state functional MRI
  • Visual stimulation

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