[Eeglablist] Filter causality pop_eegfiltnew

Makoto Miyakoshi mmiyakoshi at ucsd.edu
Fri Jan 17 11:51:34 PST 2014


Dear Vito,

> To explain quickly the problem it is obvious that if you filter in both
the directions (as an acausal filter does) you introduce a correlation
beetwen the "future" and the "past".

I see. And for within the same frequency bands the amount of the phase
shift is the same so the delay does not matter as long as GC is within the
same frequency range.

FYI, SIFT performs time-frequency decomposition so no need to band limit
the data.

Makoto

2014/1/16 Vito de Feo <vito.defeo at zmnh.uni-hamburg.de>

>  Dear Makoto,
>
> I attach you a couple of papers that illustrate the problems. To explain
> quickly the problem it is obvious that if you filter in both the directions
> (as an acausal filter does) you introduce a correlation beetwen the
> "future" and the "past".
>
> I need to filter the data to remove the 50 HZ (or 60 Hz if you are in USA
> or Japan) frequency. For the rest I don't filter.
>
> Best
>
>
> Vito
>
> Quoting Makoto Miyakoshi <mmiyakoshi at ucsd.edu>:
>
>  Dear Vito,
>
>  > the acausal filtering destroy the causality flow. For Granger it is
> important to use only causal filter.
>
>  Oh really. That sounds counterintuitive to me. Please send me the URL to
> the paper about it.
>
>  However let me tell you this that Tim Mullen (the author of SIFT) told us
> in the past EEGLAB workshop that we should not use ANY filter for SIFT. If
> you want to remove low-frequency drifts etc... he recommended the detrend
> option supported in SIFT. For low-pass filter, he said don't use it. Also
> make sure that you use double precision, not signle precision; check EEGLAB
> option to switch it (default should be single precision). Actually these
> were new things I learned!
>
>  Condro, for clarification to novice users, let me add this that EEGLAB's
> FIR filter is by default non-causal (i.e. peak latencies do not shift).
>
>  Makoto
>
> 2014/1/15 Vito de Feo <vito.defeo at zmnh.uni-hamburg.de>
>
>>
>>
>>
>>
>> *Dear Makoto, the acausal filtering destroy the causality flow. For
>> Granger it is important to use only causal filter. If you are interested I
>> can send you a paper about that. Yes, I know SIFT and I am also using it
>> for my analisys.*
>>
>>
>>
>>
>> *Vito Quoting Makoto Miyakoshi <mmiyakoshi at ucsd.edu
>> <mmiyakoshi at ucsd.edu>>:*
>>
>>
>>
>>  *Dear Andreas and Vito, *
>>
>>  *Sorry Andreas I screwed it when I typed your name.*
>>
>>  *Vito, I would like to learn from you the reason why you want to use
>> the minimum phase filter for Granger causality analysis. By the way, you
>> know SIFT is available for it? In case you don't know it yet, check
>> out http://sccn.ucsd.edu/wiki/SIFT <http://sccn.ucsd.edu/wiki/SIFT>.*
>>
>>  *Makoto*
>>
>>
>> *2014/1/14 Vito de Feo <vito.defeo at zmnh.uni-hamburg.de
>> <vito.defeo at zmnh.uni-hamburg.de>>*
>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>> *Dear Andreas, I download the last version (13.1.1) and now the option
>>> is present and it is clearly written that the default is the zero-phase
>>> linear filtering. In my previous version (the last of the EEGLAB 12) this
>>> option was not present but now, with the version 13, it is present again!
>>> Best, Vito *
>>>
>>>
>>> *Quoting Andreas Widmann <widmann at uni-leipzig.de
>>> <widmann at uni-leipzig.de>>:*
>>>
>>> *Dear Vito,*
>>>>
>>>> *in the last eeglab version there is not the minphase parameter in the
>>>>> pop_eegfiltnew function.*
>>>>
>>>> *Which version is your last version? In 13.1.1 from the web page and in
>>>> rev 10261 from SVN the option is present. It was initially introduced in
>>>> EEGLAB 13 (but not backported to EEGLAB 12). Could you please check whether
>>>> possibly something went wrong with your setup/path and report back your
>>>> version number?*
>>>>
>>>> *It was useful to force the filter to be causal. If I have understand
>>>>> well now the filter is causal by dafault because it uses the filter
>>>>> funcion. Is this correct?*
>>>>
>>>>
>>>>
>>>>
>>>> *NO! Causal non-linear filter is NOT the default. Default is and will
>>>> remain zero-phase linear filtering. Default filter functions did not change
>>>> since EEGLAB 12. Best, Andreas*
>>>>
>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> *Sorry if this is a vey well known issue but I didn't find any answer
>>>>> on the web until now. I need filter causality for Granger analisys. If
>>>>> anyone has also other suggestion about causal filtering with eeglab, any
>>>>> suggestion is very welcome! Thank in advange! Vito -- Pflichtangaben gemäß
>>>>> Gesetz über elektronische Handelsregister und Genossenschaftsregister sowie
>>>>> das Unternehmensregister (EHUG): Universitätsklinikum Hamburg-Eppendorf
>>>>> Körperschaft des öffentlichen Rechts Gerichtsstand: Hamburg
>>>>> Vorstandsmitglieder: Prof. Dr. Christian Gerloff (Vertreter des
>>>>> Vorsitzenden) Prof. Dr. Dr. Uwe Koch-Gromus Joachim Prölß Rainer Schoppik
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>>>>> <eeglablist-request at sccn.ucsd.edu>-- Makoto Miyakoshi Swartz Center for
>>>>> Computational Neuroscience Institute for Neural Computation, University of
>>>>> California San Diego _______________________________________________
>>>>> Eeglablist page: http://sccn.ucsd.edu/eeglab/eeglabmail.html
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>>>>
>>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>> *-- Pflichtangaben gemäß Gesetz über elektronische Handelsregister und
>>> Genossenschaftsregister sowie das Unternehmensregister (EHUG):
>>> Universitätsklinikum Hamburg-Eppendorf Körperschaft des öffentlichen Rechts
>>> Gerichtsstand: Hamburg Vorstandsmitglieder: Prof. Dr. Christian Gerloff
>>> (Vertreter des Vorsitzenden) Prof. Dr. Dr. Uwe Koch-Gromus Joachim Prölß
>>> Rainer Schoppik*
>>>
>>
>>
>>
>> *-- *
>>
>>
>> *Makoto Miyakoshi Swartz Center for Computational Neuroscience Institute
>> for Neural Computation, University of California San Diego*
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> *-- Pflichtangaben gemäß Gesetz über elektronische Handelsregister und
>> Genossenschaftsregister sowie das Unternehmensregister (EHUG):
>> Universitätsklinikum Hamburg-Eppendorf Körperschaft des öffentlichen Rechts
>> Gerichtsstand: Hamburg Vorstandsmitglieder: Prof. Dr. Christian Gerloff
>> (Vertreter des Vorsitzenden) Prof. Dr. Dr. Uwe Koch-Gromus Joachim Prölß
>> Rainer Schoppik*
>>
>
>
>
> --
> Makoto Miyakoshi
> Swartz Center for Computational Neuroscience
> Institute for Neural Computation, University of California San Diego
>
>
>
>
>
> --
> Pflichtangaben gemäß Gesetz über elektronische Handelsregister und
> Genossenschaftsregister sowie das Unternehmensregister (EHUG):
>
> Universitätsklinikum Hamburg-Eppendorf
> Körperschaft des öffentlichen Rechts
> Gerichtsstand: Hamburg
>
> Vorstandsmitglieder:
> Prof. Dr. Christian Gerloff (Vertreter des Vorsitzenden)
> Prof. Dr. Dr. Uwe Koch-Gromus
> Joachim Prölß
> Rainer Schoppik
>



-- 
Makoto Miyakoshi
Swartz Center for Computational Neuroscience
Institute for Neural Computation, University of California San Diego
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