[FieldTrip] Using PPC method

[Andreas Wutz]

Dear Tianyang,

maybe it's a good idea to download the accompanying sample data from the tutorial and look if you can recreate the shown data structure. Then look closer into the values of the respective fields. That should give you a better grasp on what is required there.

I have not fully looked into the code but my feeling is that spikeTrials.timestamp is not of any further use and is just carried from the data structure before (which was not cut into trials and where the raw timestamps were useful). The timing of spikes relative to the trial zero point is fully described in the fields ".time", ".trial" and ".trialtime".
Best,
Andreas


From: fieldtrip-bounces at science.ru.nl [fieldtrip-bounces at science.ru.nl] on behalf of 马天阳 [tianyangma2013 at gmail.com]
Sent: Monday, August 28, 2017 5:31 PM
To: FieldTrip discussion list
Subject: Re: [FieldTrip] Using PPC method

Dear Andreas,

I still don't quite understand the tutorial.

spikeTrials =
         label: {'sig002a_wf'  'sig003a_wf'}
     timestamp: {[1x83601 int32<http://www.mathworks.com/access/helpdesk/help/techdoc/ref/int32.html>]  [1x61513 int32<http://www.mathworks.com/access/helpdesk/help/techdoc/ref/int32.html>]}
      waveform: {[1x32x83601 double<http://www.mathworks.com/access/helpdesk/help/techdoc/ref/double.html>]  [1x32x61513 double<http://www.mathworks.com/access/helpdesk/help/techdoc/ref/double.html>]}
          unit: {[1x83601 double<http://www.mathworks.com/access/helpdesk/help/techdoc/ref/double.html>]  [1x61513 double<http://www.mathworks.com/access/helpdesk/help/techdoc/ref/double.html>]}
           hdr: [1x1 struct<http://www.mathworks.com/access/helpdesk/help/techdoc/ref/struct.html>]
        dimord: '{chan}_lead_time_spike'
           cfg: [1x1 struct<http://www.mathworks.com/access/helpdesk/help/techdoc/ref/struct.html>]
          time: {[1x83601 double<http://www.mathworks.com/access/helpdesk/help/techdoc/ref/double.html>]  [1x61513 double<http://www.mathworks.com/access/helpdesk/help/techdoc/ref/double.html>]}
         trial: {[1x83601 double<http://www.mathworks.com/access/helpdesk/help/techdoc/ref/double.html>]  [1x61513 double<http://www.mathworks.com/access/helpdesk/help/techdoc/ref/double.html>]}
     trialtime: [600x2 double<http://www.mathworks.com/access/helpdesk/help/techdoc/ref/double.html>]

Like here, I don't know why for timestamp,time and trial, there are same number of values. If I have one unit, 60 trials and focus on -0.5 s to 0.5 s around stimulus event, I think trial means which trial of the 60 trials has spikes in this 1 s. The time means time point of spikes located in the 1 s around stimulus for each trial. Is it correct? But what about the timestamp? It means from the beginning of recording to the end and has nothing to do with trials?

I feel I am quite lost.

Best,

Tianyang
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