Make spectrogram of LFP using chronux package

Hello! I am trying to get a spectrogram of some LFP signals using the chronux package.

My current code is:

[S,t,f] = chronux.ct.mtspecgramc(data, [.4 .0005], params);

S = 10*log10(S);

imagesc(t,f,S)

Because the data is sleep LFP, I should be getting a spectrogram with red on the bottom throughout, but instead, it's looking like this:

Does anyone know what I am doing incorrectly?

Answer 1

[Bjorn Gustavsson]

From the help of that function you will see that the output S should be:

0050 %       S       (spectrum in form time x frequency x channels/trials if trialave=0;
0051 %               in the form time x frequency if trialave=1)
0052 %       t       (times)
0053 %       f       (frequencies)
0054 %       Serr    (error bars) only for err(1)>=1

Therefore the correcter way of displaying the spectrogram would be:

pcolor(t,f,S.'),shading flat,colorbar,xlabel('time'),ylabel('freq')

HTH

[Selena]

Thank you, it seems to be working now!

[Bjorn Gustavsson]

My pleasure, happy that it helped.