Dictlearning

DictLearning Model Doc

Overview

DictLearning is a classical non-deep-learning method for resting-state network decomposition.

• Model family: non-deep-learning unsupervised decomposition method
• Typical objectives:
  • identify sparse resting-state networks from preprocessed fMRI
  • extract dictionary component maps and subject-level time series
  • derive interpretable network summaries for downstream connectivity or clustering
• Primary input: preprocessed resting-state fMRI, optional mask, optional group subject list
• Primary output: dictionary component maps, subject time series, optional connectomes or reports

In NeuroClaw, this document is model-level guidance for DictLearning-based resting-state decomposition workflows rather than phenotype prediction.

Upstream preparation should usually be delegated to:

• fmri-skill for rs-fMRI preprocessing, nuisance regression, filtering, and standard-space alignment
• nilearn-tool for concrete DictLearning fitting and component export

Research use only.

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Quick Start

1) Prepare resting-state inputs

Expected inputs:

• preprocessed resting-state BOLD images
• optional confounds TSV files
• optional brain mask
• optional subject list or cohort manifest

If these are not ready, delegate to fmri-skill first.

2) DictLearning route

Representative operations:

• load preprocessed resting-state images
• fit sparse dictionary learning for network decomposition
• export dictionary component maps and subject time series
• optionally use outputs for connectome or clustering analysis

Example execution route:

# delegated through claw-shell after preprocessing is confirmed
python skills/nilearn-tool/scripts/rest_dictlearning_reference.py \
  --input-list path/to/rest_bold_list.txt \
  --mask path/to/group_mask.nii.gz \
  --n-components 20 \
  --output-dir run_models_output/dictlearning

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Input / Output Contract

Required inputs

• preprocessed resting-state fMRI in subject space or standard space
• subject list or image list

Optional inputs

• confounds table(s)
• mask image
• repetition time (TR)
• decomposition parameters such as number of components
• group/covariate table for downstream statistical analysis

Produced outputs

• 4D component map image
• subject-level component time series
• component report figures and summary tables
• optional component correlation matrix / connectome

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Recommended Delegation

• resting-state preprocessing and denoising -> fmri-skill
• concrete implementation of DictLearning -> nilearn-tool
• shell execution and logging -> claw-shell

No execution before explicit plan confirmation.

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When to Use DictLearning

• The user wants resting-state network decomposition rather than task activation analysis.
• The goal is to identify sparse intrinsic connectivity networks from rs-fMRI.
• The user wants subject-level component time series for downstream connectivity or clustering.
• Sparse and interpretable network components are preferred.
• A lightweight classical unsupervised method is preferred over deep learning.

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Limitations and Notes

• Results are sensitive to preprocessing quality, head motion, filtering, and masking choices.
• The number of components strongly influences decomposition granularity.
• DictLearning is unsupervised and does not directly provide statistical group inference.
• Downstream comparisons across groups usually require additional statistical analysis after decomposition.

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Reference

• Varoquaux G et al. Dictionary learning for resting-state fMRI atlas extraction.
• Nilearn decomposition documentation: https://nilearn.github.io/stable/connectivity/resting_state_networks.html

Created At: 2026-04-14 00:31 HKT Last Updated At: 2026-04-14 00:45 HKT Author: chengwang96