Cited by 817Functional Brain Connectivity StudiesAdvanced MRI Techniques and ApplicationsAdvanced Neuroimaging Techniques and Applications

How Many Subjects Constitute a Study?

Friston, Karl J., Holmes, Andrew P., Worsley, Keith J.·1999·NeuroImage

Abstract

In fMRI there are two classes of inference: one aims to make a comment about the "typical" characteristics of a population, and the other about "average" characteristics. The first pertains to studies of normal subjects that try to identify some qualitative aspect of normal functional anatomy. The second class necessarily applies to clinical neuroscience studies that want to make an inference about quantitative differences of a regionally specific nature. The first class of inferences is adequately serviced by conjunction analyses and fixed-effects models with relatively small numbers of subjects. The second requires random-effect analyses and larger cohorts.

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Crossref · 10.1006/nimg.1999.0439

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  • Small sample sizes can still inform about the typicality of a feature in a population when the feature is present in most sampled cases.

    “However, small sample sizes can be informative about typicality of a feature in a population, when features are identified in the majority of cases sampled[18].”

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Authors
Friston, K. J., Holmes, A. P., & Worsley, K. J.
Affiliations
National Hospital for Neurology and Neurosurgery (GB)
Venue
NeuroImage
Publisher
Elsevier BV
Published
1999-07
Volume
10
Issue
1
Pages
1-5
ISSN
1053-8119 (ISSN-L)
OpenAlex
W1966363088
Cited by
814
References
0
Citations by year
2026: 2 · 2025: 6 · 2024: 3 · 2023: 7 · 2022: 9 · 2021: 8 · 2020: 17 · 2019: 13 · 2018: 10 · 2017: 15 · 2016: 31 · 2015: 27 · 2014: 22 · 2013: 35 · 2012: 30
Type
journal article
Language
en
Open access
closed
Locations
  • NeuroImage (publishedVersion)
  • PubMed (publishedVersion)
  • UCL Discovery (University College London) (submittedVersion)
Funders
Wellcome Trust
Topics
  • Life Sciences › Neuroscience › Cognitive Neuroscience › Functional Brain Connectivity Studies
  • Health Sciences › Medicine › Radiology, Nuclear Medicine and Imaging › Advanced MRI Techniques and Applications
  • Health Sciences › Medicine › Radiology, Nuclear Medicine and Imaging › Advanced Neuroimaging Techniques and Applications
Keywords
sample size, functional MRI, statistical inference, population inference, fixed effects model, random effects models, conjunction analysis, clinical neuroscience, functional anatomy, cohort size
MeSH terms
Data Interpretation, Statistical, Humans, Magnetic Resonance Imaging, Research Design, Models, Statistical, Cohort Studies, Patient Selection

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