Implementation of Spectogram Code

Is there is any difference between the following codes?

 NS = Noisy Signal;

 windowsize = 128;
 window = hanning(windowsize);nfft = windowsize;noverlap = windowsize-1;

 [S_NS F_NS T_NS P_NS] = spectrogram(NS,window,noverlap,nfft,Fs,'yaxis');
 AMP_NS = 10*log10(abs(S_NS));
 imagesc(T_NS*1e3,F_NS*1e-6,AMP_NS)

and

 spectrogram(NS,window,noverlap,nfft,Fs,'yaxis');