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Psychometrika

, Volume 78, Issue 2, pp 308–321 | Cite as

An Introduction to Normalization and Calibration Methods in Functional MRI

  • Thomas T. LiuEmail author
  • Gary H. Glover
  • Bryon A. Mueller
  • Douglas N. Greve
  • Gregory G. Brown
Article

Abstract

In functional magnetic resonance imaging (fMRI), the blood oxygenation level dependent (BOLD) signal is often interpreted as a measure of neural activity. However, because the BOLD signal reflects the complex interplay of neural, vascular, and metabolic processes, such an interpretation is not always valid. There is growing evidence that changes in the baseline neurovascular state can result in significant modulations of the BOLD signal that are independent of changes in neural activity. This paper introduces some of the normalization and calibration methods that have been proposed for making the BOLD signal a more accurate reflection of underlying brain activity for human fMRI studies.

Key words

functional MRI arterial spin labeling cerebral blood flow quantitative fMRI calibrated fMRI hypercapnia 

Notes

Acknowledgements

We acknowledge funding support by the NIH National Center for Research Resources for the FBIRN consortium (Grant U24-RR021992) as well as individual grants to coinvestigators: P41-RR009784 (GHG), R01NS051661, and R01MH084796 (TTL).

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Copyright information

© The Psychometric Society 2012

Authors and Affiliations

  • Thomas T. Liu
    • 1
    Email author
  • Gary H. Glover
    • 2
  • Bryon A. Mueller
    • 3
  • Douglas N. Greve
    • 4
  • Gregory G. Brown
    • 5
  1. 1.Center for Functional MRIUniversity of California San DiegoLa JollaUSA
  2. 2.Department of RadiologyStanford UniversityStanfordUSA
  3. 3.Department of Psychiatry, CMRRUniversity of MinnesotaMinneapolisUSA
  4. 4.Department of Radiology, Martinos Center for Biomedical ImagingMassachusetts General HospitalCharlestownUSA
  5. 5.VA San Diego Healthcare System, Psychology Service (116B) and Department of PsychiatryUniversity of California San DiegoSan DiegoUSA

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