Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2009 Jun;4(2):208-13.
doi: 10.1093/scan/nsp011.

Independence in ROI analysis: where is the voodoo?

Russell A Poldrack  1 , Jeanette A Mumford
Affiliations

Independence in ROI analysis: where is the voodoo?

Russell A Poldrack et al. Soc Cogn Affect Neurosci. 2009 Jun.

Abstract

We discuss the effects of non-independence on region of interest (ROI) analysis of functional magnetic resonance imaging data, which has recently been raised in a prominent article by Vul et al. We outline the problem of non-independence, and use a previously published dataset to examine the effects of non-independence. These analyses show that very strong correlations (exceeding 0.8) can occur even when the ROI is completely independent of the data being analyzed, suggesting that the claims of Vul et al. regarding the implausibility of these high correlations are incorrect. We conclude with some recommendations to help limit the potential problems caused by non-independence.

PubMed Disclaimer

References

    1. Aron A.R., Gluck M.A., Poldrack R.A. Long-term test-retest reliability of functional MRI in a classification learning task. Neuroimage. 2006;29:1000–6. - PMC - PubMed
    1. Begley S. Of voodoo and the brain. Newsweek. 2009 VLIII, 25.
    1. Bennett C.M., Miller M.B., Wolford G.L. Organization for Human Brain Mapping Abstracts. 2009. Neural correlates of interspecies perspective taking in the post-mortem Atlantic Salmon: an argument for multiple comparisons correction.
    1. Chumbley J.R., Friston K.J. False discovery rate revisited: FDR and topological inference using Gaussian random fields. Neuroimage. 2009;44:62–70. - PubMed
    1. Fischl B., Salat D.H., Busa E., et al. Whole brain segmentation: automated labeling of neuroanatomical structures in the human brain. Neuron. 2002;33:341–55. - PubMed