[FieldTrip] ft_preprocessing high-pass filtering question

[Aaron Schurger]

Thanks, Thomas. What if I wanted to apply the filtering to the entire
time series first, and then extract the trial epochs after filtering?
Is there a way to do that?
Thanks,
Aaron

On Thu, Jul 4, 2013 at 4:31 PM, Thomas Hartmann
<thomas.hartmann at th-ht.de> wrote:
> hi aaron,
> filtering is generally applied after the data have been epoched. to avoid
> the filter artifacts you are speaking about, we normally define epochs that
> are sufficiently larger so that these artifacts would be in data we are not
> interested in. about 1s at both ends of the epoch should be enough in most
> cases. but you better check... later you can use ft_redefinetrial to discard
> that extra data.
> hope this helps.
> best,
> thomas
>
>
>
> Aaron Schurger <aaron.schurger at gmail.com> schrieb:
>>
>> Hi,
>> When you read in a data file using ft_preprocessing, with high-pass
>> filtering, is the high-pass filter applied before the data are epoched
>> (i.e. on the entire time series for the whole data file), or is the
>> high-pass filter applied separately to each epoch? For very low
>> frequencies (with period longer than one data epoch) this will make a
>> difference.
>> Thanks!
>> Aaron
>>
>> --
>> Aaron Schurger, PhD
>> Post-doctoral researcher
>> INSERM U992 / NeuroSpin
>> CEA - Saclay, France
>> +33-1-69-08-66-47
>> aaron.schurger at gmail.com
>> http://www.unicog.org
>> ________________________________
>>
>> fieldtrip mailing list
>> fieldtrip at donders.ru.nl
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>
>
> Dr. Thomas Hartmann
>
> CIMeC - Center for Mind/Brain Sciences
> Università degli Studi di Trento
> via delle Regole, 101
> 38060 Mattarello (TN)
> ITALY
>
> Tel: +39 0461 28 2779
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> Email: thomas.hartmann at th-ht.de
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>
> "I am a brain, Watson. The rest of me is a mere appendix. " (Arthur Conan
> Doyle)
>
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-- 
Aaron Schurger, PhD
Post-doctoral researcher
INSERM U992 / NeuroSpin
CEA - Saclay, France
+33-1-69-08-66-47
aaron.schurger at gmail.com
http://www.unicog.org