[Eeglablist] crossf function option 'alpha' usage

[arno delorme]

Dear Kyongsik,

the coherence values returned are not masked by significance. To mask  
them you need to use the 'cohboot' threshold values. There is one  
threshold value for each frequency in 'cohboot', so you need to use  
repmat to make 'cohboot' the same size as 'coh'

mask    = coh > repmat(cohboot, [ 1 size(coh,2) ]); % mask of 0 and 1
figure; imagesc(timesout, freqsout, coh .* mask); % plot
cl = caxis; caxis([-cl(2) cl(2)]); % color axis

Best,

Arno

On 1 nov. 08, at 04:41, Kyongsik Yun wrote:

> I used
> [coh,mcoh,timesout,freqsout,cohboot,cohangles]= pop_newcrossf( eeg,  
> 1, i, j, [-2000  1998], [3         0.5] ,'type', 'phasecoher',  
> 'topovec', [i  j], 'elocs', chanlocs, 'chaninfo', chaninfo, 'alpha',  
> 0.01,'padratio', 4);
>
> I obtained 'coherence' color coded time-frequency map. I saw the non- 
> significant output values as green in the map.
> As far as I know, this 'coherence' values is in the variable 'coh'.  
> However, I cannot find any '0' values in 'coh', while the map shows  
> 'green'.
> This is strange.
>
> I want to get statistically significant 'phase coherence' values  
> using option 'alpha', but I think I misued the option 'alpha' or  
> something.
>
> Thank you.
>
> Kyongsik Yun

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