Here we provide the code to reproduce all results from the paper:
"A 7T fMRI dataset of synthetic images for out-of-distribution modeling of vision".
Alessandro T. Gifford, Radoslaw M. Cichy, Thomas Naselaris, Kendrick Kay

Large-scale datasets of brain responses such as the Natural Scenes Dataset (NSD) are boosting computational neuroscience research by enabling models of the brain with performances beyond what was possible just a decade ago. However, these datasets lack out-of-distribution (OOD) components, which are crucial for the development of more robust models. Here, we address this limitation by releasing NSD-synthetic, a dataset consisting of 7T fMRI responses from the same eight NSD participants for 284 synthetic images. We show that NSD-synthetic’s fMRI responses reliably encode stimulus-related information and are OOD with respect to NSD. Furthermore, we provide a proof of principle that OOD generalization tests on NSD-synthetic reveal differences between models of the brain that are not detected with the original NSD data; we demonstrate that the degree of OOD (quantified as the distance between a set of responses and the training data used for modeling) is predictive of the magnitude of model failures; and we show that the concept of OOD is not restricted to artificial stimuli but can be usefully applied even within the domain of naturalistic stimuli. These results showcase how NSD-synthetic enables OOD generalization tests that facilitate the development of more robust models of visual processing and the formulation of more accurate theories of human vision.

The NSD dataset (including NSD-synthetic) is freely available at http://naturalscenesdataset.org.

This repository contains code to reproduce all paper's results.

To run the code, you first need to install the libraries in the requirements.txt file within an Anaconda environment. Here, we guide you through the installation steps.

First, create an Anaconda environment with the correct Python version:

conda create -n nsdsynthetic_env python=3.9

Next, download the [requirements.txt][requirements] file, navigate with your terminal to the download directory, and activate the Anaconda environment previously created with:

source activate nsdsynthetic_env

Now you can install the libraries with:

pip install -r requirements.txt

• 00_prepare_fmri: Prepare NSD-synthetic and NSD-core's fMRI responses for the following analyses.
• paper_figure_2: Analyse NSD-synthetic's univariate and multivariate fMRI responses, and noise ceiling signal-to-noise ratio (ncsnr).
• paper_figure_3: Perform multidimensional scaling (MDS) on NSD-synthetic and NSD-core's fMRI responses.
• paper_figure_4: Train encoding model on NSD-core, and test them both in-distribution (NSD-core) and out-of-distribution (NSD-synthetic).
• paper_figure_5: Compare diffent encoding models based on their in-distribution (NSD-core) and out-of-distribution (NSD-synthetic) performances.
• paper_figure_6: Compare the out-of-distribution generalization performance of encoding models tested on individual NSD-synthetic image classes.
• paper_figure_7: Compare the generalization performance of encoding models tested both in- and out-of-distribution on NSD-core, and out-of-distribution on NSD-synthetic.

In Figures 2, 4-7, we plotted results on flattened cortical surfaces using pycortex' fsaverage subject.

For visualization purposes, we manually drew surface labels based on the “streams” ROI collection as provided in the NSD data release. To use these labels, add the overlays.svg file to the pycortex fsaverage subject folder (within an Anaconda environment, you should find this folder at: ../anaconda3/envs/env_name/share/pycortex/db/fsaverage).

If you experience problems with the code submit an issue, or get in touch with Ale (alessandro.gifford@gmail.com).

If you use any of our data or code, please cite:

• Gifford AT, Cichy RM, Naselaris T, Kay K. 2025. A 7T fMRI dataset of synthetic images for out-of-distribution modeling of vision. arXiv preprint, arXiv:2503.06286. DOI: https://doi.org/10.48550/arXiv.2503.06286
• Allen EJ, St-Yves G, Wu Y, Breedlove JL, Prince JS, Dowdle LT, Nau M, Caron B, Pestilli F, Charest I, Hutchinson BJ, Naselaris T, Kay K. 2022. A massive 7T fMRI dataset to bridge cognitive neuroscience and artificial intelligence. Nature neuroscience, 25(1), 116-126. DOI: https://doi.org/10.1038/s41593-021-00962-x