Rest-task modulation of fMRI-derived global signal topography is mediated by transient coactivation patterns

PLoS Biol. 2020 Jul 10;18(7):e3000733. doi: 10.1371/journal.pbio.3000733. eCollection 2020 Jul.

Abstract

Recent resting-state functional MRI (fMRI) studies have revealed that the global signal (GS) exhibits a nonuniform spatial distribution across the gray matter. Whether this topography is informative remains largely unknown. We therefore tested rest-task modulation of GS topography by analyzing static GS correlation and dynamic coactivation patterns in a large sample of an fMRI dataset (n = 837) from the Human Connectome Project. The GS topography in the resting state and in seven different tasks was first measured by correlating the GS with the local time series (GSCORR). In the resting state, high GSCORR was observed mainly in the primary sensory and motor regions, whereas low GSCORR was seen in the association brain areas. This pattern changed during the seven tasks, with mainly decreased GSCORR in sensorimotor cortex. Importantly, this rest-task modulation of GSCORR could be traced to transient coactivation patterns at the peak period of GS (GS-peak). By comparing the topography of GSCORR and respiration effects, we observed that the topography of respiration mimicked the topography of GS in the resting state, whereas both differed during the task states; because of such partial dissociation, we assume that GSCORR could not be equated with a respiration effect. Finally, rest-task modulation of GS topography could not be exclusively explained by other sources of physiological noise. Together, we here demonstrate the informative nature of GS topography by showing its rest-task modulation, the underlying dynamic coactivation patterns, and its partial dissociation from respiration effects during task states.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Brain Mapping*
  • Connectome
  • Female
  • Humans
  • Magnetic Resonance Imaging*
  • Male
  • Prosencephalon / physiology
  • Reproducibility of Results
  • Respiration
  • Rest / physiology*
  • Signal Processing, Computer-Assisted*
  • Task Performance and Analysis*
  • Time Factors
  • Young Adult

Associated data

  • Dryad/10.5061/dryad.xsj3tx9bw

Grant support