[Eeglablist] EOG

[Joseph Dien]

I see!  For the dataset I made this for, I didn't need the events so I  
didn't fully implement the event coding.  If anyone needs this, I'd be  
willing to update the code just to continue supporting it.  If no one  
needs the event coding, I won't bother.

Cheers!

Joe

On Monday, September 1, 2003, at 07:00 PM, Arnaud Delorme wrote:

> Dear Joe,
>
> your code imported events as data arrays. These arrays encode latency  
> in a special maner (the number in the array being used as latency  
> offset with respect to the begining of each block). Since we had  
> already some code for decoding these arrays into events (in our  
> non-compressed ERPSS reading function), we though we would use it  
> rather than redo everything in your code.
> If you want to fix it in your code, I suggest you look at the  
> read_erpss function we implemented. I also sugest that you use the  
> attached function (which is a modified version of your function  
> allowing speed up of up to 1000; note that this function requires the  
> mex files distributed in EEGLAB).
>
> Best
>
> Arno
>
> Dien, Joseph wrote:
>
> What was the problem with the data events?  No one told me they ran  
> into a
> problem with my code.  I'm no longer working with ERPSS data but might  
> be
> willing to fix it if it wasn't too much trouble.
>
> Cheers!
>
> Joe
>
>
> -----Original Message-----
> From:	Arnaud Delorme [mailto:arno at salk.edu]
> Sent:	Fri 8/29/2003 6:47 PM
> To:	Timothy O'Keefe
> Cc:	eeglablist at sccn.ucsd.edu
> Subject:	Re: [Eeglablist] EOG
>
> Timothy O'Keefe wrote:
>
>
> That seems odd to me because we are able to import bipolar VEO and HEO
>
> into EEGLAB (we use Digitize acquisition software whcih records into
>
> erpss format). They both come up as channels 63 and 64 (as they are
>
> recorded) AND we have imported and exported (without running ICA) and
>
> the output yeilds identical datasets. I don't know if that could be a
>
> result of how MANSCAN codes bipolar electrodes? Though Arno did say  
> that
>
> "EEGLAB can not yet handle properly bipolar channels". That is  
> confusing
>
> to me because we have had no problems as of yet removing blinks.
>
> The current problem is that EEGLAB does not store a reference for each
> channel. As a result, it can not make the difference between eye  
> channels
> recorded in a bipolar montage and eye channels recorded using the same
> reference as the EEG scalp electrodes. To solve this problem, in the  
> future,
> we intend to include a reference for each channel in the channel  
> structure.
> This is why EEGLAB cannot handle eye channels properly.
>
> What would happen if you run ICA on all channels (including bipolar
> channels)?
> We expect that ICA might dedicate (in theory) some components to  
> account for
> the different references. In theory, we think that ICA component  
> should be
> able to resolve the multiple reference problem and find some kind of  
> common
> reference.
> However no study has been done on this yet.
>
> Does
>
> readses.m fix this (Arno, you should know about readses.m)?  I'm not so
>
> sure cuz Iv'e used the read_erpss function and that reads them in fine
>
> too.
>
> Neither readses() nor read_erpss() fix this problem (readses() is not  
> an
> eeglab function; it was kindly sent to us to import compressed ERPSS  
> data
> but, since it could not handle data events properly, we chose to  
> augment our
> read_erpss() function to import compressed ERPSS data).
>
>
>
> Also, we reference everything to the nose inc. HEO and VEO.
>
> We think that this is the best option if you are planning to include  
> these
> channels in the ICA decomposition.
>
> Arno
>
>
>
>
>
> --
>
> Arnaud Delorme, Ph.D.
> Computational Neurobiology Lab, Salk Institute
> 10010 North Torrey Pines Road
> La Jolla, CA 92037 USA
>
> Tel : (+1)-858-458-1927 ext 15
> Fax : (+1)-858-458-1847
> Web page : www.sccn.ucsd.edu/~arno
>
>
> <readses.m>
------------------------------------------------------------------------ 
--------

Joseph Dien
Assistant Professor of Psychology
Department of Psychology
419 Fraser Hall
1415 Jayhawk Blvd
University of Kansas
Lawrence, KS 66045-7556
E-mail: jdien at ku.edu
Office: 785-864-9822
Fax: 785-864-5696
http://people.ku.edu/~jdien/Dien.html
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