Correlation of the electrical and intrinsic optical signals in the chickenspreading depression phenomenon

This paper presents some results on the correlation between the electrophys iological and intrinsic optical signals (IOS) of spreading depression waves in chicken retinae. We first show that the peak of the time derivative of the electrophysiological wave occurs precisely when the optical signal reac hes the electrode tip. Second, by comparing bath applications of propranolo l and glycerol it can be shown that the slow potential shift is not directl y correlated to the intrinsic optical signal. Propranolol depresses the amp litude of the electrical wave, although the intrinsic optical signal contin ues being visible. On the other hand, we observe total absence of the IOS u nder glycerol, while the electrical wave is always present. Correlations of this kind are relevant for a deeper understanding of the underlying mechan isms of the spreading depression phenomenon. (C) 2001 Elsevier Science Irel and Ltd. All rights reserved.