BIPHASIC OPTICAL SIGNAL OF AN OSCILLATING NONSTATIONARY BELOUSOV–ZHABOTINSKY BULK REACTION AND ITS SIMILARITY TO SOME NEUROPHYSIOLOGICAL EVENTS

Abstract

Oscillating chemical bulk reactions of the Belousov–Zhabotinsky (BZ) type usually show a well-defined periodical color change representing the underlying chemical reactions. Models including up to more than 50 coupled reactions have been developed to describe the BZ-reaction in detail, however, typically a much simpler set of equations is used (i.e. the Brüsselator, the FKN, or the FitzHugh–Nagumo model). There are various types of oscillating reactions with color changes, for example, from transparent to yellow ( Ce catalyzed), or from blue to red (Ferroin catalyzed). In equilibrium systems and in models each color-change is usually a simple curve with one maximum, and the oscillation is stable in time. We have investigated the detailed structure of the intrinsic optical signal (IOS) of a BZ-reaction in-depth andfound, in a nonstationary ferroin catalyzed BZ-reaction, a much more complex optical behavior. Amazingly, this IOS with its detailed time dependence very much resembles electrical and optical signals from important neuronal processes. These are especially the sodium current during action potentials (AP) and the retinal spreading depression (SD). The time-scale of all these processes can be different by decades. This principal similarity, however, points to a deeper common theoretical basis of all these processes as assumed up to now, and makes the presented type of BZ-reaction an ideal model for a variety of neurophysiological signals, although the mechanisms are strictly different.