Error in calling up MEM to Compute Sources

[robertknowlton]

I have a new Windows PC, and a have installed the 260130 build (today) without Matlab. The one issue I am having is using MEM. Whenever I call up MEM for source reconstruction I get the following error. I’ve not run into this before. See screenshot below of Error_Insufficient_number_of_outputs_from_right_and_side.

[Raymundo.Cassani]

Hello Robert,

Before addressing the issue you are experiencing, from the screenshot it shows you are using One global channel file, this option is never recommended, because:

1. A global channel file is problematic as projectors SSP, ICA or even Rereferencing is stored there, this will introduce problems, e.g. if you two raw files are pre-processed differently, or if more subjects are added to the protocol.
2. A global channel file implies: a global head model and a global noise covariance, thus a shared kernel. This is not correct as the kernel will vary depending on the noise level in the recordings for different subjects.

The recommendation is to use on channel file per Study. i.e., the option:
No, use one channel file per acquisition run when creating a new Subject.

More info in here:
https://neuroimage.usc.edu/brainstorm/Tutorials/CreateProtocol#Create_your_first_protocol

---

Now, regarding the issue you are experiencing, this is caused as the MEM panel did not handle the case of a global channel, as it expects the "one channel file per acquisition run" setup.

(@edelaire, we may want to add a check for the channel-file approach used by the Subject and show warnings or errors accordingly. This error has its origin here)

[edelaire]

Hello,

@Raymundo.Cassani

(@edelaire, we may want to add a check for the channel-file approach used by the Subject and show warnings or errors accordingly. This error has its origin here)

Do you have a suggestion on how to achieve this ?

@Raymundo.Cassani

The recommendation is to use on channel file per Study. i.e., the option:
No, use one channel file per acquisition run when creating a new Subject.

Is there any reason why we keep the option to share channel file accross subject ? Maybe it would be easier to just not propose the option since there is no clear benefit.

[Raymundo.Cassani]

@edelaire

Do you have a suggestion on how to achieve this ?

Retrieve the Subject with bst_get() and check the field UseDefaultChannel
0: One channel file per run
1: One channel file per Subject
2: One channel file per Protocol

@edelaire

Is there any reason why we keep the option to share channel file accross subject ?

Legacy, support for older scripts that users may have.
While it is not recommended, there are valid cases to use that option.

[edelaire]

@Raymundo.Cassani

Retrieve the Subject with bst_get() and check the field UseDefaultChannel
0: One channel file per run
1: One channel file per Subject
2: One channel file per Protocol

Thx. i’ll push a fix sometime this week.

Edouard