common filter in source analysis

[Ingrid Nieuwenhuis]

Dear Lin,



It could have multiple causes. Under the assumption that the location of the
sources is not different in pre and post, only the power, the common filters
can lead to better results, because you use more data to construct the
filters. Especially when you have a strong beta decrease in post compared to
pre (almost no power in post, much power in pre) using the data in pre in
the filters, can help to get better localization in post. It all depends to
a large degree on your data. To decide which result you can trust, you could
compare the results on source level, with the sensor level.



I hope this helps,

Ingrid



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From: FieldTrip discussion list [mailto:FIELDTRIP at NIC.SURFNET.NL] On Behalf
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Sent: Monday, February 16, 2009 11:30 AM
To: FIELDTRIP at NIC.SURFNET.NL
Subject: [FIELDTRIP] common filter in source analysis



Dear all,



I'm trying to use beamforming to calculate the sources of beta activities to
the tutorial's data. I got very different results by using common filter to
pre and post (according to the event) conditions comparing with the
un-common filtered method.



Do you have any idea why this happens? Thank you very much!



Best,

Lin

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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. See also http://listserv.surfnet.nl/archives/fieldtrip.html and http://www.ru.nl/fcdonders/fieldtrip.
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