Models of membranes of cerebral cells as substrates for information storage.

The past decade has seen a growing understanding of functional capacities and structural organization of cell membranes. Studies in immunology, endocrinology and neurobiology have led to some unifying concepts about processes of transduction at the membrane surface, and the coupling of surface events to the interior of the cell. My interest in these problems has been directed in no small measure by interactions with Lars Onsager. His kindly tutelage and rigorous criticism have been a source of endless encouragement to those who sought the full measure of his wisdom in the difficult area of the energetics of membrane excitation. Onsager's unflagging interest in mechanisms of ion transportation led him to earnest consideration of a variety of non-classical models of conduction in proteins, always tempered by his deep insight essential aspects of physical chemistry. My discussions with him at the MIT Neuroscience Research Program were a regular stimulus to the experiments which our groups have undertaken in search of answers to questions raised by the models presented here. Above all, Lars Onsager was a kindly, gentle man. In this personal example, he will be as sadly missed as for his broad and imaginative approach to critical questions in the physical and biological sciences.