A few random questions

This forum deals with BCI2000 configuration issues.
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Elizabeth
Posts: 19
Joined: 20 Jan 2005, 16:29

A few random questions

Post by Elizabeth » 20 Jan 2005, 17:27

Hello,

I just have 4 random questions about the BCI setup. I looked through all the documentation, but needed some clarification on a few things:

1. Is there a way to have the EEG Source Signal window display more than 16 channels?

2. Does the BaselineHits matrix update on its own? Does it matter what starting values are put into the 2nd column (as long as there is a row for each target)?

3. When would SpatialFilteredChannels not be the same number as TransmitCh?

4. When is appropriate to change the SpatialFilteredKernal matrix to something other than a unity matrix?

I really appreciate anyone's help! :D

Thanks,
Elizabeth

gschalk
Posts: 615
Joined: 28 Jan 2003, 12:37

Re: Random Questions

Post by gschalk » 21 Jan 2005, 17:13

Elizabeth,

Here are the answers to your questions:

1. Is there a way to have the EEG Source Signal window display more than 16 channels?

Right-click on the EEG display will give you a number of options. You can always scroll using the cursor keys (EEG display has to be active).

2. Does the BaselineHits matrix update on its own? Does it matter what starting values are put into the 2nd column (as long as there is a row for each target)?

This depends on whether certain adaptation variables in Statistics are turned on. You should have one row for each target. First column should be target number and second should be target probability (1/NumberTargets).

3. When would SpatialFilteredChannels not be the same number as TransmitCh?

When you do not have a square matrix.

4. When is appropriate to change the SpatialFilteredKernal matrix to something other than a unity matrix?

Whenever you would like to 're-reference' the signal. For example, in EEG people routinely use a 'Large Laplacian' filter. This essentially subtracts from a particular channel the average of some surroudning channels (to get rid of spatial noise). In this case, you might have five columns (for 5 TransmitCh) and only one row for one output SpatialFilteredChannel.

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