How to average spectrograms of real signals

Hello, I'm trying to average spectrograms of different trials of a voltage signal from an EEG electrode. I'm just not sure that I'm doing it correctly because I don't know much about this subject.

ov = 8;
sg = 24;
Fs = 128; 

for i=1:80
   [~,~,~,spec(:,:,i)] = spectrogram(trials(i,:),sg,ov,[],Fs);
end
m_spec = mean(spec,3);
[~,F,T] = spectrogram(trials(1,:),sg,ov,[],Fs);
imagesc(F,T,10*log10(m_spec)),axis xy,colormap(jet);

this is based on something I saw here on the website but I'm not sure about it. I know from my teacher that i need to average the "pxx arguements" of the spectrogram, and I thought it's the PSD variable from the documentation:" [S,F,T,P] = spectrogram(...) P is a matrix representing the Power Spectral Density (PSD) of each segment. "

Thank you, sorry if the question is confused.