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

[Arjen Stolk]

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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