Andy's BrainCast

Andrew Jahn

Andy talks to the leading scientists and software developers in the field of neuroimaging, learning about the latest trends, interesting findings, and the future of brain science.

Episodes

  1. Bayesian Statistics and Individualized Neuroimaging | Amanda Mejia (Andy's BrainCast #005)

    19/02/2025

    Bayesian Statistics and Individualized Neuroimaging | Amanda Mejia (Andy's BrainCast #005)

    Today's guest is Amanda Mejia, an associate professor in the Department of Statistics at Indiana University. Dr. Mejia is the director of the StatMIND lab (https://www.statmindlab.com/), which develops statistical methods for the analysis of brain imaging data, including principled statistical and Bayesian approaches. The goal of these techniques is to increase statistical power and reliability, and also to advance the generalizability of fMRI studies to more diverse populations. Currently, she is collaborating with other researchers to apply these methods to a range of topics, including neurodegenerative diseases, neonatal development, and psilocybin therapy. Dr. Mejia will be hosting a half-day educational workshop at 2025's Organization for Human Brain Mapping Conference, focusing on incorporating spatial information into fMRI analysis: https://ww6.aievolution.com/hbm2501/Events/viewEv?ev=2297 She is also one of the lecturers for Robert Welsh's Advanced Statistical Methods in Neuroimaging and Genetics (https://medicine.utah.edu/psychiatry/advanced-statistics) Papers Discussed =============== Eklund et al. (2012) paper on pre-whitening: https://www.sciencedirect.com/science/article/pii/S1053811912003825?casa_token=15Pk6_RjtzsAAAAA:rPz-6S-KhJOeo_hp7cuU2qX5SIhL5YpT4S1hvdj9RPOIHnqrbQKaclUrFwpNxbo9S1iP-mcM_Q Eklund et al. (2016) paper on spatial autocorrelation and multiple comparisons correction in fMRI analyses: https://www.pnas.org/doi/pdf/10.1073/pnas.1602413113 Lindquist (2008): The Statistical Analysis of fMRI Data https://www.researchgate.net/profile/Martin-Lindquist/publication/45857794_The_Statistical_Analysis_of_fMRI_Data/links/0912f5099351f63829000000/The-Statistical-Analysis-of-fMRI-Data.pdf?_sg%5B0%5D=started_experiment_milestone&origin=journalDetail Lindquist & Mejia (2015): Zen and the Art of Multiple Comparisons: https://pmc.ncbi.nlm.nih.gov/articles/PMC4333023/ Table of Contents ============== 00:00 Introduction to StatMind Lab and Its Focus 02:54 Precision Medicine and Individualized Analysis 06:04 The Evolution of fMRI in Clinical Settings 09:01 Statistical Techniques in Neuroimaging 11:46 Bayesian Approaches in fMRI Analysis 15:02 Frequentist vs Bayesian: A Balanced Perspective 17:56 Resources for Understanding fMRI Data 21:07 Training the Next Generation of Researchers 23:03 Interdisciplinary Learning in Statistics 24:26 Innovative Teaching Tools for Data Science 27:18 Workshops and Educational Opportunities 29:54 Reproducibility in Research 33:01 Leveraging Large Datasets for Insights 40:05 Challenges of Longitudinal Data Analysis

    47 min
  2. 25/08/2024

    Effect Magnitude, P-Values, and Statistical Power | Gang Chen (Andy's BrainCast #001)

    In this episode, we talk with Gang Chen, a mathematical statistician at the Scientific and Statistical Computing Core (SSCC) of the National Institutes of Health. Gang is one of the developers of the fMRI analysis package Analysis of Functional NeuroImages (AFNI: https://afni.nimh.nih.gov/). He has written about several topics related to statistics in neuroimaging, in particular his latest blog post about thresholding for statistical significance and what effects this may have on reproducibility: https://discuss.afni.nimh.nih.gov/t/enhancing-result-reporting-in-neuroimaging/7453 We talk about this and other topics, including statistical power, reproducibility, and whether the phrase "statistically significant" should be retired in favor of something else. Links to other papers discussed: -The Neuroimaging Analysis Replication and Prediction Study (NARPS, Botvinik-Nezer et al., 2020: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7771346/ -Vul et. al (2009), Puzzlingly High Correlations: https://tinyurl.com/yc26nuur -Eklun et. al (2016), Cluster Failure: https://www.pnas.org/doi/pdf/10.1073/pnas.1602413113 -Chen et. al (2017), Effect Sizes and P-Values: https://tinyurl.com/5eb7d6r3 -Taylor et. al (2023), Highlighting vs. Hiding Results: https://www.sciencedirect.com/science/article/pii/S1053811923002896 -Allen et. al (2012), Reporting Neuroimaging Results: https://www.cell.com/neuron/fulltext/S0896-6273(12)00428-X Table of Contents ============== 0:00 Introduction for Gang Chen 1:39 Effect Sizes (Magnitudes) and P-Values: What is the Difference? 10:48 Difficulty in Adopting New Reporting Standards: Beta Values and Percent Signal Change 13:13 Reviewing Previous Statistical "Crises" in Neuroimaging: Vul, Eklund, Bennet, and the NARPS Paper 21:43 Highlight vs. Hiding Results: Taylor et al. (2023) 25:46 The Problem with Dichotomizing Results: Reproducibility and P-Hacking 29:52 Statistical Power: Issues and Recommendations 38:38 Open-Access Datasets and Statistical Power 40:03 How Widespread is Requiring Power Analyses for Grants? 42:18 Meta-Analyses: Potential Problems with Reporting Peak T-Statistics 45:05 Pre-Registered Reports and Reproducibility 47:46 Should we Consider Replacing the Phrase, "Statistically Significant"? 54:45 Papers about Hierarchical Models 56:20 Concluding Remarks

    58 min

About

Andy talks to the leading scientists and software developers in the field of neuroimaging, learning about the latest trends, interesting findings, and the future of brain science.