The empirical replicability of task-based fMRI as a function of sample size

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • Ghent University
  • Heidelberg University 
  • King's College London (KCL)
  • Trinity College Dublin
  • University of Mannheim
  • French Alternative Energies and Atomic Energy Commission (CEA)
  • University of Vermont
  • University of Nottingham
  • Charité – Universitätsmedizin Berlin
  • Physikalisch-Technische Bundesanstalt
  • INSERM - Institut national de la santé et de la recherche médicale
  • University of Göttingen
  • TUD Dresden University of Technology
  • Berlin Institute of Health at Charité

Abstract

Replicating results (i.e. obtaining consistent results using a new independent dataset) is an essential part of good science. As replicability has consequences for theories derived from empirical studies, it is of utmost importance to better understand the underlying mechanisms influencing it. A popular tool for non-invasive neuroimaging studies is functional magnetic resonance imaging (fMRI). While the effect of underpowered studies is well documented, the empirical assessment of the interplay between sample size and replicability of results for task-based fMRI studies remains limited. In this work, we extend existing work on this assessment in two ways. Firstly, we use a large database of 1400 subjects performing four types of tasks from the IMAGEN project to subsample a series of independent samples of increasing size. Secondly, replicability is evaluated using a multi-dimensional framework consisting of 3 different measures: (un)conditional test-retest reliability, coherence and stability. We demonstrate not only a positive effect of sample size, but also a trade-off between spatial resolution and replicability. When replicability is assessed voxelwise or when observing small areas of activation, a larger sample size than typically used in fMRI is required to replicate results. On the other hand, when focussing on clusters of voxels, we observe a higher replicability. In addition, we observe variability in the size of clusters of activation between experimental paradigms or contrasts of parameter estimates within these.

Details

Original languageEnglish
Article number116601
Pages (from-to)1-12
Number of pages12
JournalNeuroImage
Volume212
Publication statusE-pub ahead of print - 7 Feb 2020
Peer-reviewedYes

External IDs

PubMed 32036019
ORCID /0000-0001-5398-5569/work/161890718

Keywords

ASJC Scopus subject areas

Keywords

  • Coherence, Reliability, Replicability, Reproducibility, Stability, Task-based fMRI

Library keywords