A Python Library for the Analysis of fMRI Data Based on Local Estimation of Hemodynamic Response Function J. Arias, P. Ciuciu, M. Dojat, F. Forbes, A. Frau-Pascual, T. Perret, J. M. Warnking 

1. Introduction “Begin at the beginning”, the King said, very gravely, “and go on till you come to the end; then stop.” -- Lewis Carroll, Alice in Wonderland 2 

× The current fMRI methods (e.g., SPM) estimates the neural activity using a canonical HRF for the whole brain. × There are local variations of the HRF in brain regions of patients with anomalies (e.g., Stenosis). Conjecture: Local variations of the HRF in patients with anomalies cause a wrong estimation of the neural activity. 3 Motivation 

× Separate estimation of the response function (HRF) × A Bayesian framework allows to account for prior knowledge × A parcellation is used to deal with the HRF estimation regionally. JDE is solved with Variational Expectation Maximization (VEM). 4 Joint Detection-Estimation (JDE) 

“Never send a human to do a machine’s job” -- Agent Smith, The Matrix 5 2. PyHRF 

6 PyHRF × Open source software × Pythonic × Robust scientific libraries × e.g., scipy, numpy, scikit-learn, nilearn, nipype ... × Implementation of several models × MCMC-BOLD, JDE-BOLD, JDE-ASL … × Parallel computation × Documentation, Notebooks, Docker image http://www.pyhrf.org https://github.com/pyhrf 

7 PyHRF 

8 PyHRF http://www.neurovault.org/images/307 Posterior Probability Map (PPM) Z-Scores Right Hand Gorgolewski, K. J., Storkey, A., Bastin, M. E., Whittle, I. R., Wardlaw, J. M., & Pernet, C. R. (2013). A test-retest fMRI dataset for motor, language and spatial attention functions. GigaScience, 2(1), 6. https://doi.org/10.1186/2047-217X-2-6 

× Improvement of the PyHRF API for further developments × Bring PyHRF to clinicians (GUI, CLI). × Pythonic framework from acquisition to visualization × Interaction SPM PyHRF Show the variations of the HRF response in brain regions of patients with anomalies (e.g., Stenosis). 9 Semavi Project 

Semavi Project Stimuli & Acquisition Pre- processing Analysis 10 PyHRF 

11 Semavi Project 

Semavi Project 12 I f 

Alice: “How long is forever?” White Rabbit: “Sometimes, just one second. -- Lewis Carroll, Alice in Wonderland 13 3. Concluding Remarks 15 minutes 

× PyHRF allows to estimate the HRF locally × Open source software × Multiplatform (Conda, Docker) × Extensible framework for the fMRI workflow Now we have a powerful tool for non-experts that will allow to test our hypothesis and new ideas. 14 Summary 

× Continue to improve PyHRF × Internships × Use of PyHRF for the analysis of small animals × rats × Calibration of some parameters of the model to be able to compare our results with SPM × ROC analysis Show the variations of the HRF response in brain regions of patients with anomalies (e.g., Stenosis). 15 Future Work 

Thanks! Any questions?