Search Results

Empirical data from experimental psychology, primate neurophysiology, and neuropsychological observations of brain damaged patients are the primary generators of experimental hypotheses for functional neuroimaging experiments in spatial neurocognition: the way in which space is mapped from early sensory codes (e.g., retinotopic maps, somatotopic maps) through transformation to higher-order coordinates. This chapter discusses the multicomponent nature of space representation and the existence of several spatial frames (e.g., far as opposed to near space); the distinction between object- and space-based visual cognition; the relationship between space and motion cognition; and the modulation of spatial representation and perception through attentional mechanisms.

This chapter investigates the possibility of knowing a structure (an isomorphism type) more directly than as the structure of all models of this or that categorical theory. It starts with grasp of small simple finite structures by means of visual templates and then explains how visual grasp of structures may be possible without templates. The case is then made for the possibility of visual cognition of an infinite structure, an ω-sequence, though this is visual cognition of a more abstract kind, relying on the distinction between a visual category specification and a visual image. It is argued that this kind of cognition is not available for many other structures such as that of the closed unit interval of reals under ‘less-than’, but it is available for some ordinal structures beyond ω. The chapter uses this to explain and support some contentious claims of Kurt Gödel.

Visual processing of biological motion by living organisms is crucial for adaptive social behavior and nonverbal communication. Investigations of how the perception of body motion operates in populations with developmental disorders of different etiologies can provide important insights into the neural mechanisms that underlie social perceptions. This chapter describes the role of structural and functional brain connectivity for biological motion perception and visual social cognition.

This problem of object persistence has been studied in several disciplines in cognitive science. In this chapter, the authors review the many contexts in which spatiotemporal priority drives computations of object persistence as the authors propose explanations at several levels for why spatiotemporal priority plays this dominant role. The principle of spatiotemporal priority describes a general solution to types of correspondence problems as it struggles with the many guises in visual cognition research — including the tunnel effect, apparent motion, illusory conjunctions, and object reviewing. This principle captures some of the primary features of the dominant ‘object file’ model of object persistence. It accounts for the perception of persisting objects not only in adult humans but also in infants and nonhuman primates. Lastly, the principle may have a firm foundation in both mechanistic and functional terms.

This book is a result of the joint research project on the image enhancement of ancient documents. It brings together researches and projects in such way techniques and results could be discussed in a way which would capitalize the possibilities of cross-fertilization, of generalizing techniques from a category of object or problem to another, and encourage people to think laterally and in interdisciplinary way on advancing techniques of imaging and visual understanding of objects under study. It aims to instil awareness of the extent to which scientific contributions are thinking about subjectivity of interpretation, visual cognition, and the need to improve methods of presenting evidence in ways which feed their scientific thinking and encourage genuine innovation of approach to developing methods of image enhancement. The chapters of this volume offer a wide range of treatment of artefacts and of techniques, many of which could be applied to a broader range of materials. While this volume did not include all scientific techniques and artefacts, it includes all artefacts which require three-dimensional (3D) imaging techniques. In this volume, the main themes are: imaging documents, laser imaging, 3D reconstructions, reconstruction of faces and depth perception from relief.

This chapter summarizes some of the work examining visual cognition through recordings of single neurons in the human medial temporal lobe (MTL). These recordings were performed in patients with pharmacologically intractable epilepsy as part of the procedure to determine the seizure focus for surgical resection. Neurons respond to complex stimuli, sometimes associating seemingly distinct stimuli, typically with sparse responses and long latencies. These recordings have opened the doors to interrogate the human brain at unprecedented resolution and are beginning to reveal a bewildering complexity in the representation of the inner cognitive world.

Does it make sense to think of a mental image as a picture in the head? And if it does, how are three-dimensional objects and scenes represented in mental “pictures”? This chapter suggests that these questions can be answered using the theoretical principles of computational cognitive science, analyzing the imagery system in terms of the data structures and processes that manipulate information during imaginal thinking. In particular, it outlines a theory in which images are patterns of activation in a 3D array of cells, accessed via two overlaid coordinate systems: a fixed viewer-centered spherical coordinate system, and a movable object-centered or world-centered coordinate system. By inserting information into the array using one system, and accessing it using the other, a variety of 3D spatial information processes, such as generating, inspecting, and transforming images, recognizing shapes, and at tending to locations, can be handled within a single framework.

The goal of this book is to enable the reader to become a practicing psychophysics researcher. This book takes an integrated theoretical approach to understanding perceptual systems and human information processing. Most of the examples in the book have focused on the measurement and testing of basic properties of visual functions. These examples show research principles that may be widely exploited by using the same or very similar test designs, analyses, and adaptive testing methods to research questions in many different applications. The current chapter outlines possible applications using a common philosophy, experimental approach, and computational method in a variety of domains and highlights future directions in neuropsychophysics that integrate psychophysics, neurophysiology, and computational modeling in vision research.

This chapter provides a brief background of the book, the collective contributions of modern pioneers of visual cognition. The book covers topics from spatial vision to the study of context, from rapid perception to emotion, from attention to memory, from psychology to computational neuroscience, and from single neurons to the human brain. The rest of the chapter provides a snapshot of visual recognition and the visual world, citing examples on scene understanding and the challenges in spatial vision. It points out that people store scene memories and their regularities in memory structures that are enhanced and fine-tuned with experience. It also notes that the brain combines different scene views across eye movements to fully understand and perceive the surroundings.

This chapter describes how adaptation over short time frames (seconds) can be combined with brain imaging to study visual representations in the primate brain. The fMRI-adaptation approach, developed by Grill-Spector and her colleagues, exploits the fact that the fMRI response is reduced by repeated presentation of the same stimulus, which they attribute to the suppression of stimulus-specific neurons. Therefore, if a change in a stimulus dimension causes an increased response or ‘rebound’ from adaptation, then the population of neurons must be selective for, or code, that property. If adaptation remains constant across a change, then the population coding must be invariant to that property.

How do people recognize an object in different orientations? One theory is that the visual system describes the object relative to a reference frame centered on the object, resulting in a representation that is invariant across orientations. Chronometric data show that this is true only when an object can be identified uniquely by the arrangement of its parts along a single dimension. When an object can only be distinguished by an arrangement of its parts along more than one dimension, people mentally rotate it to a familiar orientation. This finding suggests that the human visual reference frame is tied to egocentric coordinates.

This chapter surveys the origins of monograms in the Hellenistic world and their early usage in republican and early imperial Rome, and continues with a general overview of quantitative and qualitative changes in their application in the third and fourth centuries AD. It also examines the more general cultural background to the increasing popularity of late antique monograms as protective and intercessory devices, suggesting that the growing use of such invocational monograms in visual communication paralleled the increasing popularity of acclamations in oral communication. Finally, it employs a contextualized study of the dedication monogram in the Calendar of 354 as a window into fourth-century Roman calligraphic culture. The concluding section discusses the development of a new, contemplative quality of calligraphic monograms in the late fourth century, and shows how some Neoplatonic ideas and their Christian adaptations affected late antique graphicacy.