Not valid sensors

Bugs
1

Hi, Francois

I am having problems trying to compute head model. As you know, this is the message "Not valid sensor types to estimate a head model". I searched in forum and tutorial but I still can not solve this problem. The structure of my protocol is this (figure 1). I know that eeg file from "group analysis" and subject´s folder mismatch. I try to export "EDF Channels 132" in .elp and .sfp and then import it in "group analysis" but it didnt work. I am using EGI System 128 channels + 129 (VREF) + 130 (EMG) + 131 (ECG) + 132 (Annotations). These last 4 channels are marked as bad channels.

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If I compute head model on eeg file "GSN hydrocel...." there is not problem. But I add this eeg file into subject folder, the number of channels are not equal...Besides, in another protocol I was be able to compute head model using "EDF channels (132)" (Figure 2). This protocol (both groups together) was different structure compared new protocol (one protocol by group).

![imagen|241x500](upload://4xIZS3aVoXU5dntBoEo1xkKZA99.png

I dont know how I can create a "common files" to apply one file to all subjects and why "group analysis" has been created without my decision.

Also, I have used the same structure was run correctly prior (Figure 3), but problems continue.

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Thanks in advance,
Esteban

2

Within a subject, the folder "common files" appears when you select "Default channel file: Yes, one channel file per subject" in the subject configuration.
The folder "Group analysis" is automatically created e.g. when averaging files from multiple subjects.

Note that using shared channel files, per subject or global, is not recommended, as it can lead to confusions and errors.

You should not try to import/export channel positions between folders or subjects. In your case, you should use the menu "Add EEG position" instead.

Before trying to process your own recordings, I recommend you start by following the introduction tutorials at least until #19 included, using the example dataset provided. Then follow the EEG/Epilepsy tutorial, to learn more about handling EEG data in Brainstorm.

If you still have questions after this training, please get back to us on this forum.