another coherence question

Jan Mathijs Schoffelen Jan.Schoffelen at FCDONDERS.RU.NL
Thu Nov 9 10:41:53 CET 2006

Dear Andre,

The xparam, yparam end zparam should be: time, freq, plvspctrm.
I guess the time and freq part are taken care of by the default settings.
However, your xlim seems to refer to frequencies, true?
Try cfg.ylim = [5 100] instead.



-----Original Message-----
From: FieldTrip discussion list [mailto:FIELDTRIP at NIC.SURFNET.NL] On Behalf
Of Andre Bastos
Sent: Wednesday, November 08, 2006 11:11 PM
Subject: [FIELDTRIP] another coherence question

Hello Everyone,

So I am trying to do a simple coherence measure between a single electrode
pair, PO3 and Cz. It seems like the computations are running, fine, the
problem is in trying to use singleplotER to visualize the results, which
always fails with the following error:

    Error using ==> plot, Vectors must be the same lengths.

    Error in ==> singleplotER at 287
        plot(varargin{k-1}.(cfg.xparam), P, style);

My cfg structure looks like this:
    cfg =

       zparam           = 'plvspctrm';
       xlim             = [5 100];
       cohrefchannel    = 'Cz';
       channel          = 'PO3';

The data were first run through the scalpcurrentdensity function using the
'finite' method, then time frequency analysis was compute in frequencies
1-100 using the 'mtmconvol' method with 'powandcsd' output, using the
channel = {'PO3' 'PO4' 'Cz'}, with channelcmb set to {'PO3' 'Cz'; 'PO4'
'Cz'}. Then I called freqdescriptives using cohmethod = 'plv'.

The returned data structure definetly has coherence data in it, and has a
.plvspctrm field which is 2x100x61, channelcmb x freqs x time. Ive looked
at the data and it seems to make sense, it has numbers that range from 0
to 0.5, so it seems like the plot function is really whats giving me

Any words of wisdom?

Thank You in advance,

Andre Bastos
Robertson Lab, UC Berkeley

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