The third edition of a work that defines the field of cognitive neuroscience, with extensive new material including new chapters and new contributors.

An extended examination of Libet's works led to a comprehensive reinterpretation of his results. According to this reinterpretation, the Minimum Train Duration of electrical brain stimulation should be considered as the time needed to create a brain stimulus efficient for producing conscious sensation and not as a basis for inferring the latency for conscious sensation of peripheral origin. Latency for conscious sensation with brain stimulation may occurafterthe Minimum Train Duration. Backward masking with cortical stimuli suggests a 125-300 ms minimum value (...) for the latency for conscious sensation of threshold skin stimuli. Backward enhancement is not suitable for inferring this latency. For determining temporal relations between stimuli that correspond to subjects' reports, theendof cerebral Minimum Train Duration should be used as reference, rather than its onset. Results of coupling peripheral and cortical stimuli are explained by a latency after the cortical Minimum Train Duration, having roughly the same duration as the latency for supraliminal skin stimuli. Results of coupling peripheral stimuli and stimuli to medial lemniscus (LM) are explained by a shorter LM latency and/or a longer peripheral latency. This interpretation suggests a 230 ms minimum value for the latency for conscious sensation of somatosensory near-threshold stimuli. The backward referral hypothesis, as formulated by Libet, should not be retained. Long readiness potentials preceding spontaneous conscious or nonconscious movements suggest that both kinds of movement are nonconsciously initiated. The validity of Libet's measures of W and M moments (Libet et al., 1983a) is questionable due to problems involving latencies, training, and introspective distinction of W and M. Veto of intended actions may be initially nonconscious but dependent on conscious awareness. (shrink)

This is a unique book. It is excellently written, crammed with information, wise and a pleasure to read.' ---Daniel C. Dennett, Tufts University.

Little, Brown, 1992 Review by Glenn Branch on Jul 5th 1999 Volume: 3, Number: 27.

_Behavioral and Brain Sciences_ , 15, 183-247, 1992. Reprinted in _The Philosopher's Annual_ , Grim, Mar and Williams, eds., vol. XV-1992, 1994, pp. 23-68; Noel Sheehy and Tony Chapman, eds., _Cognitive Science_ , Vol. I, Elgar, 1995, pp.210-274.

A hypothesis on the physiological conditions of consciousness is presented. It is assumed that the occurrence of states of consciousness causally depends on the formation of complex representational structures. Cortical neural networks that exhibit a high representational activity develop higher-order, self-referential representations as a result of self-organizing processes. The occurrence of such states is identical with the appearance of states of consciousness. The underlying physiological processes can be identified. It is assumed that neural assemblies instantiate mental representations; hence consciousness depends (...) on the rate at which large active assemblies are generated. The formation of assemblies involves the activation of the N-methyl-D-aspartate receptor channel complex which controls different forms of synaptic plasticity including rapid changes of the connection strengths. The various causes of unconsciousness (e.g., anaesthetics or brain stem lesions) have a common denominator: they directly or indirectly inhibit the formation of assemblies. (shrink)

The book is an extended study of the problem of consciousness. After setting up the problem, I argue that reductive explanation of consciousness is impossible , and that if one takes consciousness seriously, one has to go beyond a strict materialist framework. In the second half of the book, I move toward a positive theory of consciousness with fundamental laws linking the physical and the experiential in a systematic way. Finally, I use the ideas and arguments developed earlier to defend (...) a form of strong artificial intelligence and to analyze some problems in the foundations of quantum mechanics. (shrink)

Behav. and Brain Sci., 8, 558-566. Libet, B. (1987). 'Consciousness: Conscious, Subjective Experience.' In Encyclopedia of Neuroscience , ed. G. Adelman. ...

For the uninitiated, there are two major tendencies in the modeling of human cognition. The older, tradtional school believes, in essence, that full human cognition can be modeled by dividing the world up into distinct entities -- called __symbol s__-- such as “dog”, “cat”, “run”, “bite”, “happy”, “tumbleweed”, and so on, and then manipulating this vast set of symbols by a very complex and very subtle set of rules. The opposing school claims that this system, while it might be good (...) at concluding that Paris is the capital of France or that there must be blood flowing in the left-rear leg of a cow, can never capture the full measure -- indeed, the essence -- of human cognition. For them, the essential features of cognition emerge from the combined effects of myriad, tiny actions far below the surface of consciousness. This is the camp to which Paul Churchland belongs. (shrink)

In this provocative book, Fred Dretske argues that to achieve an understanding of the mind it is not enough to understand the biological machinery by means of...

In this important book, Susan Hurley sheds new light on consciousness by examining its relationships to action from various angles. She assesses the role of agency in the unity of a conscious perspective, and argues that perception and action are more deeply interdependent than we usually assume. A standard view conceives perception as input from world to mind and action as output from mind to world, with the serious business of thought in between. Hurley criticizes this picture, and considers how (...) the interdependence of perceptual experience and agency at the personal level (of mental contents and norms) may emerge from the subpersonal level (of underlying causal processes and complex dynamic feedback systems). Her two-level view has wide implications, for topics that include self-consciousness, the modularity of mind, and the relations of mind to world. The self no longer lurks hidden somewhere between perceptual input and behavioral output, but reappears out in the open, embodied and embedded in its environment. Hurley traces these themes from Kantian and Wittgensteinian arguments through to intriguing recent work in neuropsychology and in dynamic systems approaches to the mind, providing a bridge from mainstream philosophy to work in other disciplines. Consciousness in Action is unique in the range of philosophical and scientific work it draws on, and in the deep criticism it offers of centuries-old habits of thought. (shrink)

A remarkable hypothesis has recently been advanced by Libet and promoted by Eccles which claims that there is standardly a backwards referral of conscious experiences in time, and that this constitutes empirical evidence for the failure of identity of brain states and mental states. Libet's neurophysiological data are critically examined and are found insufficient to support the hypothesis. Additionally, it is argued that even if there is a temporal displacement phenomenon to be explained, a neurophysiological explanation is most likely.

Hurley’s is a difficult book to work through—partly because of its length and the complexity of its arguments, but also because each of the ten essays of which it is composed has a rather different starting point and focus, and because few of her arguments achieve real closure. Essay 2 discusses competing interpretations of Kant, essay 4 articulates nonconceptual forms of self-consciousness, essay 5 offers fresh interpretations of commissurotomy patients’ behavior, essay 6 develops an objection to Wittgenstein on rule following, (...) essay 8 attacks an alleged assumption of externalism, and chapter 10 explores the possibility of combining a “motor theory” and a “control theory” of perception. This is a very rich brew, and at least half the challenge this book presents consists in discerning its central argument and conclusion with enough precision to bring criticism to bear. (shrink)

In this book the author has collected a number of his important works and added an extensive commentary relating his ideas to those of other prominentnames in the consciousness debate. The view presented here is that of a convinced dualist who challenges in a lively and humorous way the prevailing materialist "doctrines" of many recent works. Also included is a new attempt to explain mind-brain interaction via a quantum process affecting the release of neurotransmitters. John Eccles received a knighthood in (...) 1958 and was awarded the Nobel Prize for Medicine/Physiology in 1963. He has numerous other awards honouring his major contributions to neurophysiology. (shrink)