[FieldTrip] calculating behavioural-power correlation -- follow-up questions

[Arjen Stolk]

Hey Xiaoming,

Could you tell me which version of the function you're using? That info is
specified at the bottom of the help. In my case it's % $Id:
ft_statfun_correlationT.m 10837 2015-10-30 16:06:41Z arjsto $


Yours,
Arjen

2015-11-12 9:07 GMT-08:00 Xiaoming Du <XDu at mprc.umaryland.edu>:

> Thanks Stephen, Arjen.
>
> I am using : MATLAB Version: 8.1.0.604 (R2013a) and fieldtrip-20151111.
>
> I attached the 'testdata.mat' which has cfg and data_brain. I also
> attached the error message I got from Matlab command window.
>
> Looking forward to your feedback!
>
> Best,
> Xiaoming
>
> >>> Arjen Stolk <a.stolk8 at gmail.com> 11/12/2015 11:32 AM >>>
> Hi Xiaoming,
>
> Sounds like you're using an older version of the function. Did you try
> updating fieldtrip?
>
> Yours,
> Arjen
>
> 2015-11-12 7:42 GMT-08:00 Stephen Whitmarsh <stephen.whitmarsh at ki.se>:
>
>> Dear Xiaoming,
>>
>> It is working for me, using it in sourcestatistics. Have you checked your
>> design is really only one row? I can't think of anything else.
>>
>> Cheers,
>>
>> S
>>
>> *From:* fieldtrip-bounces at science.ru.nl [mailto:
>> fieldtrip-bounces at science.ru.nl] *On Behalf Of *Xiaoming Du
>> *Sent:* 12 November 2015 16:25
>> *To:* FieldTrip discussion list <fieldtrip at science.ru.nl>
>> *Subject:* Re: [FieldTrip] calculating behavioural-power correlation --
>> follow-up questions
>>
>> Dear Arjen,
>>
>> Thanks for the updates.
>>
>> I was trying to run the following code on Fieldtrip website (
>> http://www.fieldtriptoolbox.org/faq/how_can_i_test_for_correlations_between_neuronal_data_and_quantitative_stimulus_and_behavioural_variables
>> )
>>
>> % compute statistics with correlationT
>> cfg = [];
>> cfg.statistic = 'ft_statfun_correlationT';
>> cfg.method = 'montecarlo';
>> cfg.numrandomization = 1000;
>>
>> n1 = 3; % n1 is the number of subjects
>> design(1,1:n1) = [0.6 0.9 0.1]; %here we insert our independent variable
>> (behavioral data) in the cfg.design matrix, in this case reaction times of
>> 3 subjects.
>>
>> cfg.design = design;
>> cfg.ivar = 1;
>>
>> stat = ft_freqstatistics(cfg, data_brain{:});
>>
>>   However, it gives me this error:
>>
>> Error using ft_statfun_correlationT (line 81)
>> uvar must be specified for dependent samples statistics
>>
>> Error in ft_statistics_montecarlo (line 276)
>> [statobs, cfg] = statfun(cfg, dat, design);
>>
>> Error in ft_freqstatistics (line 190)
>> [stat, cfg] = statmethod(cfg, dat, design);
>>
>> Could you provide a sample data_brain, so I can organize my data into
>> same format? Thanks!
>>
>> -Xiaoming
>>
>>
>>
>> >>> Arjen Stolk <a.stolk8 at gmail.com> 11/7/2015 11:21 PM >>>
>>
>> Dear participants in the discussion on behavioural-power correlation, and
>> interested folks,
>>
>> Following recent discussion on this mailing list (thanks to Xiaoming Du
>> and Martin Krebber), we have updated ft_statfun_correlationT, a function
>> that can be used for correlating neural and behavioral variables.
>>
>> Following the update, the correlation values calculated on genuine data
>> have not changed. However, the permutation procedure for calculating the
>> randomization distribution has. Namely, prior to the update the permutation
>> procedure would randomly permute across both the independent (e.g.,
>> behavior) and dependent variables (e.g., neural data). This procedure is
>> prone to systematic bias across the data belonging to these variables. And
>> conceptually, as outlined in a new wiki page (see below), the independent
>> and dependent variables should be statistically independent, meaning that
>> any association between these variables should be broken by randomly
>> permuting the values of the independent variable.
>>
>>
>> http://www.fieldtriptoolbox.org/faq/how_can_i_test_for_correlations_between_neuronal_data_and_quantitative_stimulus_and_behavioural_variables
>> ?
>>
>> Those that have been using ft_statfun_correlationT for calculating a
>> randomization distribution using the permutation procedure are advised to
>> update to the latest fieldtrip version and re-calculate those
>> distributions. We are sorry for any inconvenience this may cause.
>>
>> On a related note, the functionality of ft_statfun_correlationT (under
>> Pearson) is highly similar to that of ft_statfun_indepsamplesregrT. To make
>> the latter function, and others in the statfun suite, more accessible, we
>> would like to forward those interested to the above wiki page where an
>> overview is provided of the different approaches to correlating neural and
>> behavioral variables, with some example fieldtrip code.
>>
>> Yours, Arjen
>>
>> on behalf of Eric Maris and Egbert Hartstra
>>
>> 2015-10-22 2:53 GMT-07:00 Maris, E.G.G. (Eric) <e.maris at donders.ru.nl>:
>>
>> Dear participants in the discussion on behavioural-power correlation,
>>
>> My name is Eric Maris and have contributed most of the older statfuns
>> (but not ft_statfun_correlationT). Together with Arjen, I will try to
>> resolve some of the issues that have been discussed. Give us some time, and
>> we will return to you via the Discussion List.
>>
>> best,
>> Eric
>>
>>
>>
>> _______________________________________________
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>>
>>
>
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