Electrical Coupling and Normal Modes of Oscillation in Dense Excitable Cellular Structures

摘要

The study of monostable electrochemical systems, of which the best known example is the iron-nitric acid interface, has led to the concept of distributed cellular systems in which the individual cells can be in either an active or a passive state, and can influence the state of neighboring cells. Such systems show promise for the synthesis of a new class of information-processing machines, characterized by ease of manufacture, high packing density and plasticity of internal structure. They are also of considerable utility as physical models of living brain tissue. Complex electrochemical systems and living neural tissue can both sustain oscillatory activity. In living systems, such oscillations are often associated with pathological conditions: e.g. epilepsy, heart fibrillation. The present studies have experimentally demonstrated controlled electrochemical oscillations of two types: cyclic reverberation in a closed loop, and 'epileptiform' discharge in a sheet of simulated cortex. The conditions of onset and maintenance of such discharges have been determined and are well understood; it is now possible to design electrochemical oscillators or oscillation suppression systems as required, within limitations. In addition, a scaling law (analogous to those used in hydrodynamic model testing) was developed to permit the quantitative study of current distributions in morphologically complex cellular structures. Such structures may be constructed using bulk electrochemical techniques. (Author)