I fancy that many of you, like myself, have woken up in the night with a "sleeping" arm or leg. It is a very peculiar feeling to have that arm or leg, cold and lifeless, hanging there at your side as if it were something which does not belong to you. In such situations you recover some of the motor functions before the sensory functions, which en ables you to move the limb like a pendulum. For a few sec onds the arm functions as an artificial limb - a prosthesis without sensors. In general we are not aware of the importance of our sensory organs until we lose them. You do not feel the pressure of your clothes on the skin or the ring on your finger. In the nineteenth century such phenomena generally named adaptation, were studied to a great extent, partic ularly in vision, as well as in the so-called lower senses. The question whether sensory adaptation was due to changes in the peripheral sensory receptors or in the central nervous structure remained in general open until the 1920s. Then the development of the electronic arsenal gave us the means to attack the problem by direct observations of the electrical events in the peripheral as well as the central nervous system. But even today there are still some blank areas in our knowledge of adaptation."

This book is the product of a two-day symposium held at the University of Texas, Austin, in March 1978. There was double motivation for our hosting a symposium on neural mechanisms in behavior. The 1977-1978 academic year marked both the 50th anniversary of the Department of Psychology at Texas and the 30th anniversary of the famous Hixon Symposium organized by the longest serving member of the department, LLOYD JEFFRESS. PHILIP GOUGH, then chairman of the department, suggested that the department celebrate these two historic events, and honor itself in the process, by holding the first of a series of symposia on topics in experimental psychology. Approval and initial funding for this enterprise came from ROBERT KING, then Dean of Social and Behavioral Sciences; additional funds were pro vided by the Program in Cognitive Science of the Sloan Foundation. Proceeds from the sale of this volume will all pass into a fund to help support subsequent symposia and volumes. At 50 we are clearly a young department, even for a psy chology department, but psychology was at least nominally present from the beginning of The University of Texas in 1883. Then, courses in psychology were offered in the School of Philosophy and had wonderful titles, such as "Mental Science (Strictly Speaking). " In 1898, the first experimental psychology course was offered. (Or at least it was intended to be offered; the catalog indicated that it was contingent upon the availability of necessary equipment."