How do I plot running correlation of an EEG data sample using corrcoef?

I'm trying to plot the correlation coefficient of a .dat file given to me. I'm suppose to do a running correlation of the EEG data and was told to use corrcoef. I'm not getting the correct plot back. I'm getting a myriad of lines in return, see image, http://i42.tinypic.com/5wcrdd.jpg. It's suppose to look more like an EEG or ECG signal.

hold on
a=eeg2c3(95:125);
for i=1:230-(length(a)-1)
  b=eeg2c3(i:i+length(a)-1);
  %[C, lags24]=xcorr(b,a);
  [R, P]=corrcoef(b,a);
  plot (R);
  %y=[R,P];
  %v=find(y>0.9);
  %disp (R);
  %x(i)=R;
end