<html><head><style type="text/css"><!-- DIV {margin:0px;} --></style></head><body><div style="font-family:'times new roman', 'new york', times, serif;font-size:12pt"><div>Dear Geoff,</div><div><br></div><div>I haven't tried to do exactly what you're describing, but I have worked a lot with CTF data and can share some thoughts on how I would go about it if I wanted to try it. The .ds data format is quite complex, but there is one thing that works to your favor. The .ds is a directory, not a single file, and the raw data is one particular file that consists pretty much entirely of numbers (the one called .meg4) There are other files that contain the header information necessary to know how to break up those raw numbers into channels, trials, etc. So one promising avenue would be to entirely copy the whole directory, but try to modify the raw data while leaving everything else the same. So if your preprocessing is things that
leave the trial structure exactly the same (e.g. filtering, 3-rd order gradient balancing, even ICA component subtraction), then you could just overwrite the values in the raw data and keep all the old remaining files to have a valid and accurate .ds dataset. I would try doing this with a very simple operation on the data at first, such as multiplying it by 2. </div><div>On the other hand, if your preprocessing includes rejecting trials, truncating them, etc., then you would have a lot more to worry about.</div><div><br></div><div>Please post to the list again and let us know if you find a way to do it!</div><div>-Jed Meltzer</div><div>meltzerj AT nidcd.nih.gov</div><div><br></div><div style="font-family:times new roman, new york, times, serif;font-size:12pt"><br><div style="font-family:times new roman, new york, times, serif;font-size:12pt"><font size="2" face="Tahoma"><hr size="1"><b><span style="font-weight: bold;">From:</span></b>
FIELDTRIP automatic digest system <LISTSERV@NIC.SURFNET.NL><br><b><span style="font-weight: bold;">To:</span></b> FIELDTRIP@NIC.SURFNET.NL<br><b><span style="font-weight: bold;">Sent:</span></b> Tue, July 13, 2010 6:00:14 PM<br><b><span style="font-weight: bold;">Subject:</span></b> FIELDTRIP Digest - 8 Jul 2010 to 13 Jul 2010 (#2010-128)<br></font><br>Note: Forwarded message is attached.<br><br>
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<h2>FIELDTRIP Digest - 8 Jul 2010 to 13 Jul 2010 (#2010-128)</h2>
<h3>Table of contents:</h3>
<ul>
<li><a rel="nofollow" href="#S1">Call for Papers - special issue - Academic Software Applications for Electromagnetic Brain Mapping Using MEG and EEG</a>
</li><li><a rel="nofollow" href="#S2">time-frequency analysis base line correction</a>
</li><li><a rel="nofollow" href="#S3">Saving preprocessed data in a raw MEG format</a> (3)
</li><li><a rel="nofollow" href="#S4">clarification</a> (2)
</li><li><a rel="nofollow" href="#S5">cohrefchannel</a>
</li><li><a rel="nofollow" href="#S6">Aligning head across runs</a>
</li></ul>
<ol>
<a rel="nofollow" name="S1"></a><li><a rel="nofollow" name="S1">Call for Papers - special issue - Academic Software Applications for Electromagnetic Brain Mapping Using MEG and EEG</a><ul>
<li><a rel="nofollow" target="_blank" href="cid:2973@NIC.SURFNET.NL">Call for Papers - special issue - Academic Software Applications for Electromagnetic Brain Mapping Using MEG and EEG</a> (07/13)<br><b>From:</b> Robert Oostenveld <r.oostenveld@FCDONDERS.RU.NL></li></ul>
<a rel="nofollow" name="S2"></a></li><a rel="nofollow" name="S2"></a><li><a rel="nofollow" name="S2">time-frequency analysis base line correction</a><ul>
<li><a rel="nofollow" target="_blank" href="cid:2974@NIC.SURFNET.NL">time-frequency analysis base line correction</a> (07/13)<br><b>From:</b> Odelia Goldberg <odidodi@HOTMAIL.COM></li></ul>
<a rel="nofollow" name="S3"></a></li><a rel="nofollow" name="S3"></a><li><a rel="nofollow" name="S3">Saving preprocessed data in a raw MEG format</a><ul>
<li><a rel="nofollow" target="_blank" href="cid:2975@NIC.SURFNET.NL">Saving preprocessed data in a raw MEG format</a> (07/13)<br><b>From:</b> Geoff Brookshire <Geoff.Brookshire@MPI.NL>
</li><li><a rel="nofollow" target="_blank" href="cid:2977@NIC.SURFNET.NL">Re: Saving preprocessed data in a raw MEG format</a> (07/13)<br><b>From:</b> "a.stolk@fcdonders.ru.nl" <a.stolk@FCDONDERS.RU.NL>
</li><li><a rel="nofollow" target="_blank" href="cid:2978@NIC.SURFNET.NL">Re: Saving preprocessed data in a raw MEG format</a> (07/13)<br><b>From:</b> Laurence Hunt <lhunt@FMRIB.OX.AC.UK></li></ul>
<a rel="nofollow" name="S4"></a></li><a rel="nofollow" name="S4"></a><li><a rel="nofollow" name="S4">clarification</a><ul>
<li><a rel="nofollow" target="_blank" href="cid:2976@NIC.SURFNET.NL">clarification</a> (07/13)<br><b>From:</b> Odelia Goldberg <odidodi@HOTMAIL.COM>
</li><li><a rel="nofollow" target="_blank" href="cid:2979@NIC.SURFNET.NL">Re: clarification</a> (07/13)<br><b>From:</b> "a.stolk@fcdonders.ru.nl" <a.stolk@FCDONDERS.RU.NL></li></ul>
<a rel="nofollow" name="S5"></a></li><a rel="nofollow" name="S5"></a><li><a rel="nofollow" name="S5">cohrefchannel</a><ul>
<li><a rel="nofollow" target="_blank" href="cid:2980@NIC.SURFNET.NL">Re: cohrefchannel</a> (07/13)<br><b>From:</b> Marco Rotonda <marco.rotonda@GMAIL.COM></li></ul>
<a rel="nofollow" name="S6"></a></li><a rel="nofollow" name="S6"></a><li><a rel="nofollow" name="S6">Aligning head across runs</a><ul>
<li><a rel="nofollow" target="_blank" href="cid:2981@NIC.SURFNET.NL">Aligning head across runs</a> (07/13)<br><b>From:</b> Maximilien Chaumon <maximilien.chaumon@GMAIL.COM></li></ul>
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<p>The aim of this list is to facilitate the discussion between users of the FieldTrip toolbox, to share experiences and to discuss new ideas for MEG and EEG analysis.</p>
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