The functions of the somatosensory system are multiple. We use tactile input to localize and experience the various qualities of touch, and proprioceptive information to determine the position of different parts of the body with respect to each other, which provides fundamental information for action. Further, tactile exploration of the characteristics of external objects can result in conscious perceptual experience and stimulus or object recognition. Neuroanatomical studies suggest parallel processing as well as serial processing within the cerebral somatosensory system that (...) reflect these separate functions, with one processing stream terminating in the posterior parietal cortex (PPC), and the other terminating in the insula. We suggest that, analogously to the organisation of the visual system, somatosensory processing for the guidance of action can be dissociated from the processing that leads to perception and memory. In addition, we find a second division between tactile information processing about external targets in service of object recognition and tactile information processing related to the body itself. We suggest the posterior parietal cortex subserves both perception and action, whereas the insula principally subserves perceptual recognition and learning. (shrink)

One way to characterize the special relation that one has to one's own body is to say that only one's body appears to one from the inside. Although widely accepted, the nature of this specific experiential mode of presentation of the body is rarely spelled out. Most definitions amount to little more than lists of the various body senses (including senses of posture, movement, heat, pressure, and balance). It is true that body senses provide a kind of informational access to (...) one's own body, which one has to no other bodies, by contrast to external senses like vision, which can take many bodies as their object. But a theory of bodily awareness needs to take into account recent empirical evidence that indicates that bodily awareness is infected by a plague of multisensory effects, regardless of any dichotomy between body senses and external senses. Here I will argue in favour of a multimodal conception of bodily awareness. I will show that the body senses fail to fully account for the content of bodily experiences. I will then propose that vision helps compensate for the insufficiencies of the body senses in people who can see. I will finally argue that the multimodality of bodily experiences does not prevent privileged access to one's body. (shrink)

Although the mechanics of how the eye works are well understood, debate still exists as to how the complex machinery of the brain interprets neural impulses...

First published in 1995, The Visual Brain in Action remains a seminal publication in the cognitive sciences. It presents a model for understanding the visual processing underlying perception and action, proposing a broad distinction within the brain between two kinds of vision: conscious perception and unconscious 'online' vision. It argues that each kind of vision can occur quasi-independently of the other, and is separately handled by a quite different processing system. In the 11 years since publication, the book has provoked (...) considerable interest and debate - throughout both cognitive neuroscience and philosophy, while the field has continued to flourish and develop. -/- For this new edition, the text from the original edition has been left untouched, standing as a coherent statement of the authors' position. However, a very substantial epilogue has been added to the book in which Milner and Goodale review some of the key developments that support or challenge the views that were put forward in the first edition. The new chapter summarizes developments in various relevant areas of psychology, neuroscience and behaviour. It notably supplements the main text by updating the reader on the contributions that have emerged from the use of functional neuroimaging, which was in its infancy when the first edition was written. Neuroimaging, and functional MRI in particular, has revolutionized the field over the past 11 years by allowing investigators to plot in detail the patterns of activity within the visual brains of behaving and perceiving humans. The authors show how its use now allows scientists to test and confirm their proposals, based as they then were largely on evidence accrued from primate neuroscience in conjunction with studies of neurological patients. (shrink)

In The Varieties of Reference (1982), Gareth Evans claims that considerations having to do with certain basic ways we have of gaining knowledge of our own physical states and properties provide "the most powerful antidote to a Cartesian conception of the self" (220). In this chapter, I start with a discussion and evaluation of Evans' own argument, which is, I think, in the end unconvincing. Then I raise the possibility of a more direct application of similar considerations in defence of (...) common sense anti-Cartesianism. Progress in this direction depends upon a far more psychologically informed understanding of normal and abnormal bodily awareness than is generally found in philosophical discussions of these issues. In the context of my attempt at some such understanding, I go on to assess the potential of this more direct line of argument. (shrink)

There seems to be no dimension of bodily awareness that cannot be disrupted. To account for such variety, there is a growing consensus that there are at least two distinct types of body representation that can be impaired, the body schema and the body image. However, the definition of these notions is often unclear. The notion of body image has attracted most controversy because of its lack of unifying positive definition. The notion of body schema, onto which there seems to (...) be a more widespread agreement, also covers a variety of sensorimotor representations. Here, I provide a conceptual analysis of the body schema contrasting it with the body image as well as assess whether the body schema can be specifically impaired, while other types of body representation are preserved; and the body schema obeys principles that are different from those that apply to other types of body representation. (shrink)