[Mne_analysis] Matching trial counts in an oddball task

[Maryam Zolfaghar]

        External Email - Use Caution        

Hi Sheraz Khan,

Thank you for your help. I have two questions regarding this function:

Is the mechanism of  "mne.Epochs.equalize_event_count
<https://martinos.org/mne/dev/generated/mne.Epochs.html#mne.Epochs.equalize_event_counts>"
function
that it randomly picks samples from the condition with more trials so that
their occurring timing would be close to the trials in another condition
with fewer trials?

Also, this function needs events_id. In my experiment, I didn't put
different triggers/events_id for each condition. All conditions now have
identical events_id. I grouped my conditions based on my metadata. Is there
any way to update my events_id according to the metadata?


Regards,
-Maryam


On Sun, Mar 3, 2019 at 7:20 PM Sheraz Khan, PhD <sheraz at nmr.mgh.harvard.edu>
wrote:

> Hi Maryam,
>
> There are multiple approaches to equalize the epoch count across
> conditions, please look at the following example
>
>
> https://martinos.org/mne/dev/auto_tutorials/plot_stats_cluster_time_frequency_repeated_measures_anova.html?highlight=equalize_event_counts
>
> and the API documentation
>
>
> https://martinos.org/mne/dev/generated/mne.Epochs.html?highlight=equalize_event_counts#mne.Epochs.equalize_event_counts
>
> Thanks
>
> Sheraz
>
>
> >         External Email - Use Caution
> >
> > Hi all,
> >
> > I have designed an oddball visual experiment. So, I have different
> numbers
> > of trials in two conditions (standard vs deviant). For doing the
> > time-frequency analysis I have to match the trials counts in each
> > condition. In other words, I should sample from the standard condition to
> > have an identical number of trials to the deviant condition.  One way
> > could
> > be sampling randomly from the standard condition which will give me
> > different results each time I run the code. I wonder whether there is a
> > better way for matching trials count in each condition in time-frequency
> > analysis in MNE.
> >
> >
> > Regards,
> > -Maryam
> > _______________________________________________
> > Mne_analysis mailing list
> > Mne_analysis at nmr.mgh.harvard.edu
> > https://mail.nmr.mgh.harvard.edu/mailman/listinfo/mne_analysis
>
>
> -------------------------
> Sheraz Khan, M.Eng, Ph.D.
> Instructor in Radiology
>
> Athinoula A. Martinos Center for Biomedical Imaging
> Massachusetts General Hospital
> Harvard Medical School
>
> McGovern Institute for Brain Research
> Massachusetts Institute of Technology
>
> Tel:   +1 617-643-5634
> Fax:   +1 617-948-5966
> Email: sheraz at nmr.mgh.harvard.edu
>        sheraz at mit.edu
> Web:   http://sheraz.mit.edu
>


-- 
*Mary Zolfaghar,*
Ph.D. Student in Computational Cognitive Neuroscience Lab, Institute of
Cognitive Science, Dept. of Psychology and Neuroscience, CU Boulder,

Muenzinger E023
UCB 345
Boulder, CO 80309
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