[FieldTrip] missing channels and time locked grand average

Arnold Kochari a.kochari at uva.nl
Wed Aug 9 16:47:45 CEST 2017

Hi Arjen,

Thank you for the suggestion. I tried it, but in this case
just spits out NaN for the channels where some participant(s) had NaNs.
This is to be expected since that's how Matlab deals with NaNs by default. So
basically I need to find some way to do averaging within the filedtrip
datastructure that would be equivalent to matlab's 'omitnan' option.


On Fri, Aug 4, 2017 at 5:20 PM, Arjen Stolk <a.stolk8 at gmail.com> wrote:

> Hi Arnold,
> There's a cfg.method = 'nan' option in ft_channelrepair, which creates NaN
> data for specified channels. As a result, these channels are still
> considered in the group-level statistics, provided other subjects have data
> for the same channels. However, I don't know whether timelockgrandaverage
> can yet deal with these NaN channels too.
> Best,
> Arjen
> On Fri, Aug 4, 2017 at 7:45 AM, Arnold Kochari <a.kochari at uva.nl> wrote:
>> Dear FieldTrip community,
>> I have a question about what seems to be an old problem with no solution
>> posted yet.
>> I have deleted bad channels in some participants during preprocessing.
>> Now I would like to compute grand average ERPs
>> using ft_timelockgrandaverage. However, if a channel has been deleted in at
>> least one participant, the mean for it does not get calculated. What I
>> would like to see is just that the average is calculated among the
>> remaining participants.
>> I understand that there might be some strong arguments for the absence of
>> this functionality. I also know about the possibility to interpolate the
>> deleted channels using channelrepair, but I do not really agree with it.
>> Is there any way to calculate grand averages the way I would like to do
>> it? The only solution that I can think of right now is exporting the data,
>> making the calculation in R and then importing the averages it again, but
>> that would require a lot f time.
>> Kind regards,
>> Arnold Kochari
>> PhD candidate, Institute for Logic, Language and Computation, University
>> of Amsterdam
>> _______________________________________________
>> fieldtrip mailing list
>> fieldtrip at donders.ru.nl
>> https://mailman.science.ru.nl/mailman/listinfo/fieldtrip
> _______________________________________________
> fieldtrip mailing list
> fieldtrip at donders.ru.nl
> https://mailman.science.ru.nl/mailman/listinfo/fieldtrip
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.science.ru.nl/pipermail/fieldtrip/attachments/20170809/4c7c5f47/attachment-0002.html>

More information about the fieldtrip mailing list