Part I attempts to review the background, basic sources of data, concepts, and methodology to be employed in the study of perceptrons. In Chapter 2, a brief review of the main alternative approaches to the development of brain models is presented. Chapter 3 considers the physiological and psychological criteria for a suitable model, and attempts to evaluate the empirical evidence which is available on several important issues. Chapter 4 contains basic definitions and some of the notation to be used in later sections are presented. Parts II and III are devoted to a summary of the established theoretical results obtained to date. Part II (Chapters 5 through 14) deals with the theory of three-layer series-coupled perceptrons, on which most work has been done to date. Part III (Chapters 15 through 20) deals with the theory of multi-layer and cross-coupled perceptrons. Part IV is concerned with more speculative models and problems for future analysis. Of necessity, the final chapters become increasingly heuristic in character, as the theory of perceptrons is not yet complete, and new possibilities are continually coming to light. (Author).

The World In Your Head: A Gestalt View of the Mechanism of Conscious Experience represents a bold assault on one of the greatest unsolved mysteries in science: the nature of consciousness and the human mind. Rather than examining the brain and nervous system to see what they tell us about the mind, this book begins with an examination of conscious experience to see what it can tell us about the brain. Through this analysis, the first and most obvious observation is that consciousness appears as a volumetric spatial void, containing colored objects and surfaces. This reveals that the representation in the brain takes the form of an explicit volumetric spatial model of external reality. Therefore, the world we see around us is not the real world itself, but merely a miniature virtual-reality replica of that world in an internal representation. In fact, the phenomena of dreams and hallucinations clearly demonstrate the capacity of the brain to construct complete virtual worlds even in the absence of sensory input. Perception is somewhat like a guided hallucination, based on sensory stimulation. This insight allows us to examine the world of visual experience not as scientists exploring the external world, but as perceptual scientists examining a rich and complex internal representation. This unique approach to investigating mental function has implications in a wide variety of related fields, including the nature of language and abstract thought, and motor control and behavior. It also has implications to the world of music, art, and dance, showing how the patterns of regularity and periodicity in space and time--apparent in those aesthetic domains--reflect the periodic basis set of the underlying harmonic resonance representation in the brain.

This volume contains chapters derived from a N. A. T. O. Advanced Study Institute held in June 1983. As the director of this A. S. I. it was my hope that some of the e1ectrophysiologists could express the potentialities of their work for perceptual theory, and that some perceptionists could speculate on the underlying "units" of perception in a way that would engage the imagination of physio logists. The reader will have to be the judge of whether this was achieved, or whether such a psychophysiological inter1ingua is still overly idealistic. It is clear that after the revolution prec~pitated by Hube1 and Weisel in understanding of visual cortical neurons we still have only a foggy idea of the behavioral output of any particular species of cortical detector. It was therefore particularly unfortunate that two persons who have made great strides in correlating interesting facets of cat cortical physio logy with human psychophysics (Max Cynader and Martin Regan of Dalhousie University) were unable to attend this meeting. Never theless, a number of new and challenging ideas regarding both spatial perception and cortical mechanisms are represented in this volume, and it is hoped that the reader will remember not only the individual demonstrations but the critical questions posed by the apposition of the two different collections of experimental facts. David Ingle April 1984 VII TABLE OF CONTENTS PREFACE V D. N. Lee and D. S. Young Visual Timing of Interceptive Action 1 J. J.

The present collection of papers forms the Proceedings of the First Meeting on Brain Theory, held October 1-4, 1984 at the International Centre for Theoretical Physics in Trieste, Italy. The Meeting was organized with the aim of bringing together brain theorists who are willing to put their own research in the perspective of the general development of neuroscience. Such a meeting was considered necessary since the explosion of experi mental work in neuroscience during the last decades has not been accompanied by an adequate development on the theoretical side. The intensity of the discussions during the Meeting is prob ably reflected best in the report of the organizers, reprinted here following the Preface. During the Meeting it was decided that a workshop of this kind should be repeated at regular intervals of approximately 2 years. The International Centre for Theoretical Physics in Trieste has kindly agreed to act as host for future meetings. The present Meeting was supported by grants from the In ternational Centre for Theoretical Physics and the International School for Advanced Studies in Trieste, IBM-Germany through the "Stifterverband fur die Deutsche Wissenschaft" and the Max Planck-Institute for Biological Cybernetics.

Although we routinely take our vision to be veridical representations of reality, in actuality we choose (albeit unwittingly) or construct what we see. By movements of the eyes, the direction of our gaze, we create meaning. The author offers a reformulation of perception and its neural underpinnings, focusing on the active nature of perception. In his investigation of active perception and its brain mechanisms, he offers the gaze as the principal paradigm for perception. He discusses the dynamic and constrained nature of perception; the complex information processing at the level of the retina; the active nature of vision; the intensive nature of representations; the gaze of others as visual stimulus; and the intentionality of vision and consciousness.