Visualizing Megatrawls Network Matrices from Human Connectome Project

This example shows how to fetch network matrices data from HCP beta-release of the Functional Connectivity Megatrawl project.

See fetch_megatrawls_netmats documentation and the dataset description for more details.

Fetching the Megatrawls Network matrices

Fetching the partial correlation matrices of dimensionality d=300 with timeseries method ‘eigen regression’

from nilearn.datasets import fetch_megatrawls_netmats

netmats = fetch_megatrawls_netmats(
    dimensionality=300,
    timeseries="eigen_regression",
    matrices="partial_correlation",
)
# Partial correlation matrices array of size (300, 300) are stored in the name
# of 'correlation_matrices'
partial_correlation = netmats.correlation_matrices.to_numpy()

[fetch_megatrawls_netmats] Dataset created in
/home/runner/nilearn_data/Megatrawls
[fetch_megatrawls_netmats] Downloading data from
http://www.nitrc.org/frs/download.php/8037/Megatrawls.tgz ...
[fetch_megatrawls_netmats]  ...done. (1 seconds, 0 min)

[fetch_megatrawls_netmats] Extracting data from
/home/runner/nilearn_data/Megatrawls/3f1468dc43a408bf84510b07cee95049/Megatrawls
.tgz...
[fetch_megatrawls_netmats] .. done.

Visualization

Import nilearn plotting modules to use its utilities for plotting correlation matrices

from nilearn.plotting import plot_matrix, show

title = "Partial correlation matrices\n for d=300"
display = plot_matrix(partial_correlation, title=title)
show()

/home/runner/work/nilearn/nilearn/examples/01_plotting/plot_visualize_megatrawls_netmats.py:38: UserWarning: You are using the 'agg' matplotlib backend that is non-interactive.
No figure will be plotted when calling matplotlib.pyplot.show() or nilearn.plotting.show().
You can fix this by installing a different backend: for example via
        pip install PyQt6
  show()

Estimated memory usage: 100 MB