# spatio-temporal clustering - activation (AU) plot

**URL:** <https://mne.discourse.group/t/spatio-temporal-clustering-activation-au-plot/8628>\
**Category:** Support & Discussions\
**Tags:** eeg, visualization\
**Created:** [April 11, 2024, 10:57pm UTC](https://mne.discourse.group/t/spatio-temporal-clustering-activation-au-plot/8628 "2024-04-11T22:57:38Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![bmmansur](https://yyz2.discourse-cdn.com/free1/user_avatar/mne.discourse.group/bmmansur/32/142_2.png) [@bmmansur](https://mne.discourse.group/u/bmmansur)\
**Post date:** [April 11, 2024, 10:57pm UTC](https://mne.discourse.group/t/spatio-temporal-clustering-activation-au-plot/8628/1 "2024-04-11T22:57:38Z")

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MNE version: 1.2  
Operating system: Ubuntu 20.04.5 LTS

Dear MNE community,

In the tutorial " 2 samples permutation test on source data with spatio-temporal clustering" there’s a **figure** in the end showing **significant clusters**.

[https://mne.tools/stable/auto\_tutorials/stats-source-space/30\_cluster\_ftest\_spatiotemporal.html#sphx-glr-auto-tutorials-stats-source-space-30-cluster-ftest-spatiotemporal-py](https://mne.tools/stable/auto_tutorials/stats-source-space/30_cluster_ftest_spatiotemporal.html#sphx-glr-auto-tutorials-stats-source-space-30-cluster-ftest-spatiotemporal-py)

the X axis shows the time, and the **Y axis shows “activation (AU)”**. AU stands for arbitrary units. Does anyone know **how these arbitrary units are calculated** and could give me some intuition as to what they represent?

I would like to replicate this with my own data and then publish it, but I don’t know **how to label the Y axis properly**.

Is there any publication that used “spatio\_temporal\_cluster\_test” and plotted a similar graph? So that I could use it as a **reference** for my work?

I’d would greatly appreciate any help.

Best,

Bruno

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<div class="post-metadata">

**Author:** ![wmvanvliet](https://yyz2.discourse-cdn.com/free1/user_avatar/mne.discourse.group/wmvanvliet/32/100_2.png) [@wmvanvliet](https://mne.discourse.group/u/wmvanvliet)\
**Post date:** [April 15, 2024, 8:08pm UTC](https://mne.discourse.group/t/spatio-temporal-clustering-activation-au-plot/8628/2 "2024-04-15T20:08:01Z")

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The units are in samples. For each vertex, the values indicate the temporal extent of the cluster at that vertex, measured in samples.

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<div class="post-metadata">

**Author:** ![wmvanvliet](https://yyz2.discourse-cdn.com/free1/user_avatar/mne.discourse.group/wmvanvliet/32/100_2.png) [@wmvanvliet](https://mne.discourse.group/u/wmvanvliet)\
**Post date:** [April 15, 2024, 8:09pm UTC](https://mne.discourse.group/t/spatio-temporal-clustering-activation-au-plot/8628/3 "2024-04-15T20:09:05Z")

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Please note there is no such thing as a “significant cluster”. The statistical test is against the data as a whole and no statistical conclusions may be drawn from individual clusters. See here: [How NOT to interpret results from a cluster-based permutation test - FieldTrip toolbox](https://www.fieldtriptoolbox.org/faq/how_not_to_interpret_results_from_a_cluster-based_permutation_test/)

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**Author:** ![system](https://global.discourse-cdn.com/free1/uploads/mne/original/1X/85cc6bd2b69cb698a166dc6d880fb550510d0144.jpeg) [@system](https://mne.discourse.group/u/system)\
**Post date:** [April 26, 2024, 2:39pm UTC](https://mne.discourse.group/t/spatio-temporal-clustering-activation-au-plot/8628/5 "2024-04-26T14:39:29Z")

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Closed on April 26, 2024, 2:39pm UTC

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