Seeing more than the Tip of the Iceberg: Approaches to Subthreshold Effects in Functional Magnetic Resonance Imaging of the Brain

Clin Neuroradiol. 2024 Sep;34(3):531-539. doi: 10.1007/s00062-024-01422-2. Epub 2024 Jun 6.

Abstract

Many functional magnetic resonance imaging (fMRI) studies and presurgical mapping applications rely on mass-univariate inference with subsequent multiple comparison correction. Statistical results are frequently visualized as thresholded statistical maps. This approach has inherent limitations including the risk of drawing overly-selective conclusions based only on selective results passing such thresholds. This article gives an overview of both established and newly emerging scientific approaches to supplement such conventional analyses by incorporating information about subthreshold effects with the aim to improve interpretation of findings or leverage a wider array of information. Topics covered include neuroimaging data visualization, p-value histogram analysis and the related Higher Criticism approach for detecting rare and weak effects. Further examples from multivariate analyses and dedicated Bayesian approaches are provided.

Keywords: Data visualization; Functional magnetic resonance imaging; Neuroimaging; Statistics; Sub-threshold effects.

Publication types

  • Review

MeSH terms

  • Algorithms
  • Bayes Theorem
  • Brain Mapping* / methods
  • Brain* / diagnostic imaging
  • Data Interpretation, Statistical
  • Humans
  • Image Enhancement / methods
  • Image Interpretation, Computer-Assisted / methods
  • Magnetic Resonance Imaging* / methods
  • Reproducibility of Results
  • Sensitivity and Specificity