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FSLd: fMRI Diagnostic Tools for the FSL Toolkit

Saul Wyner 703-177-399 06/05/07. FSLd: fMRI Diagnostic Tools for the FSL Toolkit. What, basically, is fMRI?. Functional magnetic resonance imaging Sequential scans during some sort of cognitive behaviour & resting periods

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FSLd: fMRI Diagnostic Tools for the FSL Toolkit

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  1. Saul Wyner 703-177-399 06/05/07 FSLd: fMRI Diagnostic Tools for the FSL Toolkit

  2. What, basically, is fMRI? • Functional magnetic resonance imaging • Sequential scans during some sort of cognitive behaviour & resting periods • Scans are divided into cuboid voxels w/ time-series, as opposed to flat sheet data • fMRI analysis is to determine which voxels have are significant against noise

  3. Initial Data Preprocessing • Slice timing correction (all voxels in a slice are adjusted to the same time) • Basic motion correction (very important) • Spatial and temporal blurring, to remove artifacts, increase statistical validity • End result is a 4-d voxel/time map per subject • Ready for heavy-duty statistical analysis

  4. The Tricky Part: Statistical Analysis • Goal is a 'statistical map', to show areas of brain activation • Univariate vs. Multivariate • Model-Free vs. Model Based • General Linear Model • Haemodynamic Response Function

  5. The Next Level • Thresholding with 20,000 voxels- what are the problems? • 2-level analysis- groups and subjects

  6. Diagnostic Tools • With so much correction in 1st-level, how can you chuck raw errors? • Gross movement • Outliers • Funny-shaped heads • etc... • Very hard to see this stuff due to the sheer volume of data • Needs easy to visualize tests for fit • SPMd

  7. SPM vs. FSL • SPM(Statistical Parametric Mapping): Poorly documented, very particular, prone to customization, MATLAB function based • FSL(FMRIB Software Library): Precompiled, easy(er) to use, uses FEAT for GLM stuff, good file organization • My task- help design an FSLd with SPM functions

  8. Selection

  9. FSLd so Far

  10. Still Need To Do • Percent Change Threshold • Quantity of outliers • Better workable GUI • 3-d Display system

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