Sympathetic activity contributes to the fMRI signal

Commun Biol. 2019 Nov 18;2:421. doi: 10.1038/s42003-019-0659-0. eCollection 2019.


The interpretation of functional magnetic resonance imaging (fMRI) studies of brain activity is often hampered by the presence of brain-wide signal variations that may arise from a variety of neuronal and non-neuronal sources. Recent work suggests a contribution from the sympathetic vascular innervation, which may affect the fMRI signal through its putative and poorly understood role in cerebral blood flow (CBF) regulation. By analyzing fMRI and (electro-) physiological signals concurrently acquired during sleep, we found that widespread fMRI signal changes often co-occur with electroencephalography (EEG) K-complexes, signatures of sub-cortical arousal, and episodic drops in finger skin vascular tone; phenomena that have been associated with intermittent sympathetic activity. These findings support the notion that the extrinsic sympathetic innervation of the cerebral vasculature contributes to CBF regulation and the fMRI signal. Accounting for this mechanism could help separate systemic from local signal contributions and improve interpretation of fMRI studies.

Keywords: Neuro-vascular interactions; Neurophysiology; Non-REM sleep.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, N.I.H., Intramural

MeSH terms

  • Biomarkers*
  • Brain / blood supply
  • Brain / diagnostic imaging
  • Brain / metabolism
  • Cerebrovascular Circulation
  • Electroencephalography
  • Humans
  • Image Interpretation, Computer-Assisted
  • Image Processing, Computer-Assisted
  • Magnetic Resonance Imaging* / methods
  • Oxygen / blood
  • Oxygen / metabolism
  • Sympathetic Nervous System / diagnostic imaging*
  • Sympathetic Nervous System / metabolism*


  • Biomarkers
  • Oxygen