Arterial CO2 fluctuations modulate neuronal rhythmicity: Implications for MEG and FMRI studies of resting-state networks

Ian D. Driver*, Joseph R. Whittaker, Molly G. Bright, Suresh D. Muthukumaraswamy, Kevin Murphy

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

26 Scopus citations


A fast emerging technique for studying human resting state networks (RSNs) is based on spontaneous temporal fluctuations in neuronal oscillatory power, as measured by magnetoencephalography. However, it has been demonstrated recently that this power is sensitive to modulations in arterial CO2 concentration. Arterial CO2 can be modulated by natural fluctuations in breathing pattern, as might typically occur during the acquisition of an RSN experiment. Here, we demonstrate for the first time the fine-scale dependence of neuronal oscillatory power on arterial CO2 concentration, showing that reductions in alpha, beta, and gamma power are observed with even very mild levels of hypercapnia (increased arterialCO2). We use a graded hypercapnia paradigm and participant feedback to rule out a sensory cause, suggesting a predominantly physiological origin. Furthermore, we demonstrate that natural fluctuations in arterial CO2, without administration of inspired CO2, are of a sufficient level to influence neuronal oscillatory power significantly in the delta-, alpha-, beta-, and gamma-frequency bands. A more thorough understanding of the relationship between physiological factors and cortical rhythmicity is required. In light of these findings, existing results, paradigms, and analysis techniques for the study of resting-state brain data should be revisited.

Original languageEnglish (US)
Pages (from-to)8541-8550
Number of pages10
JournalJournal of Neuroscience
Issue number33
StatePublished - Aug 17 2016


  • Cortical oscillations
  • Functional connectivity
  • Hypercapnia
  • Magnetoencephalography
  • Physiological noise

ASJC Scopus subject areas

  • Neuroscience(all)


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