Connectome Classification: Statistical Connectomics for Analysis of Connectome Data
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1. The document discusses statistical connectomics, which is the application of statistical analysis techniques to connectome data. 2. It presents an example classification analysis that used graph-based statistical models on MR connectome data to accurately classify subjects as male or female with over 83% accuracy. 3. The analysis involved preprocessing MR imaging data into connectome graphs, constructing a robust Bayes classifier on a estimated signal subgraph, and evaluating performance through cross-validation on real brain network data as well as synthetic data.
Connectome Classification: Statistical Connectomics for Analysis of Connectome Data
- 1. Connectome Classification: Statistical Connectomics for Analysis of Connectome Data Joshua T. Vogelstein, PhD d: Applied Math. & Stats u: Johns Hopkins w: jovo.me e: joshuav@jhu.edu
- 2. Statistical Connectomics Statistics “the art of data collection and analysis” Connectomics “the study of connectomes” Statistical “the art of connectome data collection Connectomics and analysis”
- 3. Contributors Stats Carey E. Priebe Data Collection Glen A. Coppersmith Susan Resnick Mark Dredze Connectome Inference Will R. Gray Wisdom John Bogovic R. Jacob Vogelstein Jerry Prince Support: various grants
- 4. Simplest. Example. Ever. Blind People Deaf People V1 V1 A1 M1 A1 M1
- 5. Simplest. Example. Ever. Blind People Deaf People V1 No possible classifier V1 based on graph invariants can perform this insanely simple classification A1 M1 A1 M1 problem!!!
- 6. Realest. Example. Ever. MR Connectome Gender Classification statistical graph model graph invariants > 83% accuracy < 75% accuracy
- 7. Statistical Connectomics 1. Collect Data Multi-Modal MR Imaging 2. Preprocess Data MR Connectome Pipeline 3. Assumptions Signal Subgraph 4. Construct a Decision Rule Robust Bayes Plugin Classifier 5. Evaluate Performance Leave-One-Out X-Validation 6. Check Assumptions Synthetic Data Analysis 7. Extensions Relax assumptions
- 8. Statistical Connectomics 1. Collect Data Multi-Modal MR Imaging 2. Preprocess Data MR Connectome Pipeline 3. Assumptions Signal Subgraph 4. Construct a Decision Rule Robust Bayes Plugin Classifier 5. Evaluate Performance Leave-One-Out X-Validation 6. Check Assumptions Synthetic Data Analysis 7. Extensions Relax assumptions
- 9. 1. Collect Data: Multi-Modal MR Imaging • 49 senior individuals; 25 male, 24 female • diffusion: standard DTI protocol • structural: standard MPRAGE protocol
- 10. 2. Preprocess Data: MR Connectome Automated Pipeline • coherent collection of code • fully automatic and modular • about 12 hrs/subject/core • yields 70 vertex graph/subject http://www.nitrc.org/projects/mrcap/
- 11. 3. Data Assumptions: Signal Subgraph
- 12. 4. Construct a Decision Rule: Robust Bayes Plugin Classifier • asymptotically optimal and robust • finite sample niceness auv 1−auv y= ˆ puv|y (1 ˆ − puv|y ) ˆ πy ˆ ˆ (u,v)∈S
- 13. 5. Evaluate Performance: Leave-One-Out X-Validation incoherent estimator coherent estimator 0.5 misclassification rate # signal−vertices 0.5 L π ˆˆ = 0. 5 ˆ L n b = 0. 41 ˆ L c o h= 0. 16 10 0.4 0.25 20 0.3 ˆ L i n c= 0. 27 30 0 0 1 2 3 0.16 10 10 10 10 200 400 600 800 1000 log size of signal subgraph size of signal subgraph some coherent estimators zoomed in coherent estimator 0.5 lassification rate 0.5 star−vertices 15 0.4 18 0.25 0.3 0.16 21
- 14. 6. Check Assumptions: Synthetic Data Analysis Correlation Matrix 1 100 0.5 vertex 0 200 −0.5 300 −1 100 200 300 vertex
- 15. 7. Extensions • relax the independent edge assumption • relax binary edge assumption
- 16. Discussion • 83% 75% • yay statistical modeling!
- 17. Q(A) • anything?
- 18. 4. Construct a Decision Rule: Signal Subgraph Estimation • for each edge, we compute the significance of the difference between the two classes using Fisher’s exact test • the incoherent signal subgraph estimator finds the s edges that are most significant • the coherent signal subgraph estimator finds the s edges that are most significant incident to m vertices
- 19. 4. Construct a Decision Rule: Signal Subgraph Estimation negative log incoherent coherent significance matrix estimate estimate # correct = 15 # correct = 7 20 vertex n=64 40 60 20 40 60 −4.4 −1. vertex
- 20. 6. Check Assumptions: incoherent estimator coherent estimator 1 misclassification rate # star−vertices 0.75 0.7 10 0.25 0.5 Synthetic Data Analysis 20 0.5 30 0.3 0 0.18 0 1 2 3 200 400 600 800 1000 10 10 10 10 log size of signal subgraph size of signal subgraph 1 0.5 misclassification rate missed−edge rate coh 0.4 inc 0.3 nb 0.5 0.2 0.1 0 0 20 40 60 80 100 0 20 40 60 80 100 # training samples # training samples