Effects of spatial smoothing on inter-subject correlation based analysis of FMRI

Juha Pajula*, Jussi Tohka

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

41 Citations (Scopus)

Abstract

This study evaluates the effects of spatial smoothing on inter-subject correlation (ISC) analysis for FMRI data using the traditional model based analysis as a reference. So far within ISC analysis the effects of smoothing have not been studied systematically and linear Gaussian filters with varying kernel widths have been used without better knowledge about the effects of filtering. Instead, with the traditional general linear model (GLM) based analysis, the effects of smoothing have been studied extensively.In this study, ISC and GLM analyses were computed with two experimental and one simulated block-design datasets. The test statistics and the detected activation areas were compared numerically with correlation and Dice similarity measures, respectively. The study verified that 1) the choice of the filter substantially affected the activations detected by ISC analysis, 2) the detected activations according to ISC and GLM methods were highly similar regardless of the smoothing kernel and 3) the effect of spatial smoothing was mildly smaller on ISC than GLM analysis. Our results indicated that a good selection of the full width at half maximum of the Gaussian smoothing kernel for ISC was slightly larger than double the original voxel size.

Original languageEnglish
Pages (from-to)1114-1124
Number of pages11
JournalMagnetic Resonance Imaging
Volume32
Issue number9
DOIs
Publication statusPublished - 1 Nov 2014
MoE publication typeA1 Journal article-refereed

Funding

This research was supported by the Academy of Finland (grant numbers 130275 and 263785 ). Data collection and sharing for this project were provided by the International Consortium for Brain Mapping (ICBM; Principal Investigator: John Mazziotta, MD, PhD). ICBM funding was provided by the National Institute of Biomedical Imaging and BioEngineering . ICBM data are disseminated by the Laboratory of Neuro Imaging at the University of California, Los Angeles.

Keywords

  • Block-design
  • Filtering
  • Functional magnetic resonance imaging
  • FWHM
  • Gaussian filter
  • General linear model

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