During the academic year 1984/85 a study group on "Per- ception and Action" was established at the Center for Inter- disciplinary Research of the University of Bielefeld. Among the various activities of this group was a series of symposia. This volume covers the proceedings of one of the sym- posia, held in October 1984 and entitled "Generation and Modulation of Action Patterns". Bringing together scientists from diverse disciplines in gen- eral is challenging, but also hazardous. Aware of the notori- ous communication problems, it was tried to keep the number of representatives of at least the major areas of Neurobiology and Psychology about equal and to elicit pre- sentations that combine experimental findings with theoret- ical statements on major issues in motor control. Despite the different' viewpoints, concepts, research strategies, and methods as they are reflected in the present volume, there was the general impression among the participants that such a multidisciplinary effort was profitable and one step on the way to the realization of common goals and com- mon conceptual grounds.

In recent years there has been steadily increasing interest in motor behavior and a growing awareness that a person not only has to know what to do in a particular situation, but also how to do it. The question of how actions are performed is of central concern in the area of motor control. This volume provides an advanced-level treatment of some of the main issues. Experiments concerned with basic processes of motor control typ ically examine very simple movements. At first glance these tasks appear to be far removed from real-world tasks, but it should be kept in mind that they are not studied for their own sake. One of the main reasons for using them is the well-recognized, but sometimes questioned, scientific principle that basic laws may be discovered more easily in simple situations than iIi complex situations. Another reason is that the simple tasks studied constitute building blocks of more complex tasks. For example, some complex skills can be consid ered as consisting of sequences of aimed movements, although, as no one would doubt, knowing everything about these individual movements does not mean knowing everything about, for example, typing. The first two chapters of the present volume focus on behavioral and physiological studies of programming and preparation of move ments. In the first chapter D. Rosenbaum introduces the concept of a motor program that is set up in advance of the overt movement."