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upload a page for my project (#386)
* upload a page for my project * Update index.md * upload a page for my project * Update content/en/project/CVAE_ADHD/index.md --------- Co-authored-by: Lune Bellec <lune.bellec@umontreal.ca>
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---
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type: "project" # DON'T TOUCH THIS ! :)
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date: "2025-06-13" # Date you first upload your project.
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title: "CVAE-based ADHD neuroimaging analysis"
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names: [Cian-Ya Lan, Jia-Ling Sun]
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github_repo: https://github.com/Cleo-Lan-school/BHS_2025-project
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website:
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tags: [adhd, mri, cvae, iq]
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summary: "This project applies a contrastive variational autoencoder (CVAE) to Burner-preprocessed MRI data from the ADHD-200 dataset to disentangle ADHD-specific brain features from shared anatomical variation. We explore latent representations using RSA and clustering to better understand neuroanatomical heterogeneity in ADHD."
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image: "cover.png"
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---
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## Project definition
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### Background
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- Reconstruct 3D brain MRIs using CVAEs.
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- Disentangle "salient" ADHD-related features from "background" features common to both ADHD and typically developing children.
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- Assess how well the learned latent spaces reflect behavioral and clinical variation using:
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- **Silhouette Analysis**
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- **Representational Similarity Analysis (RSA)**
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### Tools
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This project used:
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- Python (NumPy, Pandas, SciPy, Scikit-learn, Matplotlib, Seaborn)
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- Keras (TensorFlow backend) for deep learning
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- UMAP for latent space visualization
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- Representational Similarity Analysis (RSA) using Kendall’s tau
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- Silhouette analysis for latent space separability
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- GitHub for version control
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### Data
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This project used the publicly available [ADHD-200 dataset](http://fcon_1000.projects.nitrc.org/indi/adhd200/), specifically the **Burner-preprocessed version**:
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- Structural MRI data processed via voxel-based morphometry (VBM)
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- Normalized 3D gray matter volumes (64×64×64)
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- Accompanied by phenotypic variables: age, sex, diagnosis, subtype, medication, IQ, etc.
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### Deliverables
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At the end of the project, we produced:
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- A working CVAE framework for modeling neuroanatomical variation
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- Visualizations of latent features and synthetic brain reconstructions
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- RSA and clustering results relating brain features to clinical data
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- Well-documented code and reproducible analysis notebooks
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## Results
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### Progress overview
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We trained a CVAE model with two latent components:
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- `s` (salient features): ADHD-specific anatomical variation
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- `z` (background features): common/shared variation
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We evaluated the model using:
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- **Silhouette scores** for latent clustering
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- **RSA** to correlate latent dimensions with phenotypic variables
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- **GMM clustering and BIC** to test for discrete vs. continuous subtype structure
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### Tools I learned during this project
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- Contrastive representation learning in generative models
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- Implementation of CVAEs in Keras
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- Preprocessing and working with VBM MRI data
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- Representational Similarity Analysis
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- Model interpretability techniques for brain data
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### Results
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#### Deliverable 1: CVAE analysis
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- Salient features (`s`) were significantly correlated with:
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- **ADHD Index**
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- **Inattentive and Hyperactive/Impulsive scores**
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- **Medication status** and **age**
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- Shared features (`z`) were more related to:
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- **IQ**, **gender**, and **scan site**
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#### Deliverable 2: Clustering analysis
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- Gaussian Mixture Models (GMM) with Bayesian Information Criterion (BIC) showed:
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- **Lowest BIC at 1 cluster**, suggesting **continuous heterogeneity**
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- Results align with dimensional models of psychiatric disorders
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#### Deliverable 3: Code and notebook
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- Full training pipeline in `Train-CVAE-ADHD200.ipynb`
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- Visualization and RSA in helper scripts
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- Readme documentation and reproducibility checklist included
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## Conclusion and acknowledgement
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This project demonstrates the potential of contrastive deep generative models like CVAEs to disentangle disorder-specific neuroanatomical features from shared variation. Our findings suggest ADHD may be better described along a spectrum rather than discrete subtypes. We thank the Brainhack School instructors and the open neuroimaging community for providing tools and data that made this project possible.

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