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AFNI Robert W Cox, PhD Biophysics Research Institute Medical College of Wisconsin Milwaukee WI.

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Presentation on theme: "AFNI Robert W Cox, PhD Biophysics Research Institute Medical College of Wisconsin Milwaukee WI."— Presentation transcript:

1 AFNI Robert W Cox, PhD Biophysics Research Institute Medical College of Wisconsin Milwaukee WI

2 AFNI  Analysis of Functional NeuroImages  Genesis (mid-1994): “Need” for MCW neuroscientists to transform FMRI activation maps to Talairach-Tournoux coordinates  Initial goals:  T-T transformation via manual AC-PC marking  Interactive browsing of image data in 5 “dimensions”: 3 spatial + imaging run + subject  Basic unit of data: 3D AFNI dataset  Big array of numbers plus geometrical information  Developed for Unix+X11+Motif (including Linux)

3 An FMRI Analysis Environment  Philosophy:  Encompass all needed classes of data and computations  Extensibility + Openness + Scalability: Anticipating what will be needed to solve problems that have not yet been posed  Interactive vs. Batch operations: Stay close to data or view from a distance  Components:  Data Objects: Arrays of 3D arrays + auxiliary data  Data Viewers: Numbers, Graphs, Slices, Volumes  Data Processors: Plugins, Plugouts, Batch Programs

4 Steps in Processing with AFNI  Image assembly into datasets [to3d ]  Can be done at the scanner with the realtime plugin  Image registration [3dvolreg]  Functional activation calculations [AFNI, 3dfim]  Linear and nonlinear time series regression [3dDeconvolve, 3dNLfim]  Transformation to Talairach coordinates [AFNI ]  Alternative: selection of anatomical ROIs [AFNI ]  Integration of results from multiple subjects [many]  Visualization of & thinking about results [AFNI & you]

5 AFNI Controller Window

6 Interactive Analysis with AFNI Graphing voxel time series data Displaying EP images from time series Control Panel

7 FIM overlaid on SPGR, in Talairach coordsMultislice layouts Looking at the Results

8 Volume Rendering Controls

9 < 1 CPU s per frame (Pentium II 400 MHz) Sample Rendering: Coronal slice viewed from side; function not cut out

10 Integration of Results  Done with batch programs (usually in scripts)  3dmerge: edit and combine 3D datasets  3dttest: voxel-by-voxel: 1- and 2-sample t-tests  3dANOVA:  Voxel-by-voxel: 1-, 2-, and 3-way layouts  Fixed and random effects  Other voxel-by-voxel statistics are available  3dpc: principal components (space  time)  ROI analyses are a labor-intensive alternative

11 Extending AFNI Package  Batch programs  Output new 3D datasets for viewing with AFNI  Plugins — searched for and loaded at startup  Add interactive capabilities to AFNI program  “Fill in the blanks” menu for input from users  40 page manual and some samples included  Plugouts — attach themselves in middle of run  External programs that communicate with AFNI with shared memory or TCP/IP sockets

12 Whole Brain Realtime FMRI  Assembly of images into AFNI datasets during acquisition  Can use AFNI tools to visualize during scanning  Realtime 3D registration  Graph of estimated motion parameters  Recursive signal processing to update activation map with each new data volume  Color overlay changes with each TR

13 The Goal: Interactive Functional Brain Mapping  See functional map as scanning proceeds 1 minute 2 minutes 3 minutes


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