The standard behavioral index for human consciousness is the ability to report events with accuracy. While this method is routinely used for scientific and medical applications in humans, it is not easy to generalize to other species. Brain evidence may lend itself more easily to comparative testing. Human consciousness involves widespread, relatively fast low-amplitude interactions in the thalamocortical core of the brain, driven by current tasks and conditions. These features have also been found in other mammals, which suggests that consciousness (...) is a major biological adaptation in mammals. We suggest more than a dozen additional properties of human consciousness that may be used to test comparative predictions. Such homologies are necessarily more remote in non-mammals, which do not share the thalamocortical complex. However, as we learn more we may be able to make “deeper” predictions that apply to some birds, reptiles, large-brained invertebrates, and perhaps other species. (shrink)

The Bayesian brain hypothesis provides an attractive unifying framework for perception, cognition, and action. We argue that the framework can also usefully integrate interoception, the sense of the internal physiological condition of the body. Our model of entails a new view of emotion as interoceptive inference and may account for a range of psychiatric disorders of selfhood.

A recent report by Persaud et al. [Persaud, N., McLeod, P. & Cowey, A. . Post-decision wagering objectively measures awareness. Nature Neuroscience 10, 257–261] addresses a fundamental issue in consciousness science: the experimental measurement of conscious content. The authors propose a novel technique, ‘post-decision wagering’, in which subjects place bets on the correctness of decisions or discriminations. In this note, I critique the authors’ claim that their method “measures awareness directly”.

Neural Darwinism (ND) is a large scale selectionist theory of brain development and function that has been hypothesized to relate to consciousness. According to ND, consciousness is entailed by reentrant interactions among neuronal populations in the thalamocortical system (the ‘dynamic core’). These interactions, which permit high-order discriminations among possible core states, confer selective advantages on organisms possessing them by linking current perceptual events to a past history of value-dependent learning. Here, we assess the consistency of ND with 16 widely recognized (...) properties of consciousness, both physiological (for example, consciousness is associated with widespread, relatively fast, low amplitude interactions in the thalamocortical system), and phenomenal (for example, consciousness involves the existence of a private flow of events available only to the experiencing subject). While no theory accounts fully for all of these properties at present, we find that ND and its recent extensions fare well. (shrink)

The metacognitive stance of Smith et al. risks ignoring sensory consciousness. Although Smith et al. rightly caution against the tendency to preserve the uniqueness of the human mind at all costs, their reasoned stance is undermined by a selective association of consciousness with high-level cognitive operations. Neurobiological evidence may offer a more general, and hence more inclusive, basis for the systematic study of animal consciousness.

This commentary considers Merker's mesodiencephalic proposal in relation to quantitative measures of neural dynamics suggested to be relevant to consciousness. I suggest that even if critical neural mechanisms turn out to be subcortical, the functional utility of consciousness will depend on the rich conscious contents generated by continuous interaction of such mechanisms with a thalamocortical envelope. (Published Online May 1 2007).

Which systems/organisms are conscious? New tests for consciousness (‘C-tests’) are urgently needed. There is persisting uncertainty about when consciousness arises in human development, when it is lost due to neurological disorders and brain injury, and how it is distributed in nonhuman species. This need is amplified by recent and rapid developments in artificial intelligence (AI), neural organoids, and xenobot technology. Although a number of C-tests have been proposed in recent years, most are of limited use, and currently we have no (...) C-tests for many of the populations for which they are most critical. Here, we identify challenges facing any attempt to develop C-tests, propose a multidimensional classification of such tests, and identify strategies that might be used to validate them. (shrink)

Sandberg et al. show that the Perceptual Awareness Scale scale is sensitive compared to confidence ratings and wagering in detecting accurate perception. They go on to argue that the PAS scale is hence a sensitive measure of conscious perception compared to confidence ratings, a claim disputed here. The fact that some visual content is conscious does not entail that the visual content relevant to making a discrimination is conscious. For example, if one saw a square but was only aware of (...) seeing a flash of something, then one has not consciously seen a square. When PAS and confidence ratings come in conflict, we suggest that it is confidence ratings that more reliably indicate the conscious status of contents allowing discrimination. (shrink)

Discrete Mathematics is designed to serve as a textbook for undergraduate engineering students of computer science and postgraduate students of computer applications. The book would also prove useful to post graduate students of mathematics. It seeks to provide a thorough understanding of the subject and present its practical applications to computer science.

Grapheme-colour synaesthesia is a perceptual experience where graphemes, letters or words evoke a specific colour, which are experienced either as spatially coincident with the grapheme inducer (projector sub-type) or elsewhere, perhaps without a definite spatial location (associator sub-type). Here, we address the question of whether synaesthesia can be rapidly produced using a hypnotic colour suggestion to examine the possibility of ‘hypnotic synaesthesia’, i.e. subjectively experienced colour hallucinations similar to those experienced by projector synaesthetes. We assess the efficacy of this intervention (...) using an “embedded figures” test, in which participants are required to detect a shape (e.g., a square) composed of local graphemic elements. For grapheme-colour synaesthetes, better performance on the task has been linked to a higher proportion of graphemes perceived as coloured. We found no performance benefits on this test when using a hypnotic suggestion, as compared to a no-suggestion control condition. The same result was found when participants were separated according to the degree to which they were susceptible to the suggestion (number of coloured trials perceived). However, we found a relationship between accuracy and subjective reports of colour in those participants who reported a large proportion of coloured trials: trials in which the embedded figure was accurately recognised (relative to trials in which it was not) were associated with reports of more intense colours occupying a greater spatial extent. Collectively, this implies that hypnotic colour was only perceived after shape detection rather than aiding in shape detection via colour-based perceptual grouping. The results suggest that hypnotically induced colours are not directly comparable to synaesthetic ones. (shrink)

This paper presents a version of neurophenomenology based on generative modelling techniques developed in computational neuroscience and biology. Our approach can be described as _computational phenomenology_ because it applies methods originally developed in computational modelling to provide a formal model of the descriptions of lived experience in the phenomenological tradition of philosophy (e.g., the work of Edmund Husserl, Maurice Merleau-Ponty, etc.). The first section presents a brief review of the overall project to naturalize phenomenology. The second section presents and evaluates (...) philosophical objections to that project and situates our version of computational phenomenology with respect to these projects. The third section reviews the generative modelling framework. The final section presents our approach in detail. We conclude by discussing how our approach differs from previous attempts to use generative modelling to help understand consciousness. In summary, we describe a version of computational phenomenology which uses generative modelling to construct a computational model of the inferential or interpretive processes that best explain this or that kind of lived experience. (shrink)

Most early studies of consciousness have focused on human subjects. This is understandable, given that humans are capable of reporting accurately the events they experience through language or by way of other kinds of voluntary response. As researchers turn their attention to other animals, “accurate report” methodologies become increasingly difficult to apply. Alternative strategies for amassing evidence for consciousness in non-human species include searching for evolutionary homologies in anatomical substrates and measurement of physiological correlates of conscious states. In addition, creative (...) means must be developed for eliciting behaviors consistent with consciousness. In this paper, we explore whether necessary conditions for consciousness can be established for species as disparate as birds and cephalopods. We conclude that a strong case can be made for avian species and that the case for cephalopods remains open. Nonetheless, a consistent effort should yield new means for interpreting animal behavior. (shrink)

Overgaard, Timmermans, Sandberg, and Cleeremans ask if the conscious experience of people in implicit learning experiments can be explored more fully than just confidence ratings allow. We show that confidence ratings play a vital role in such experiments, but are indeed incomplete in themselves: in addition, use of structural knowledge attributions and ratings of fringe feelings like familiarity are important in characterizing the phenomenology of the application of implicit knowledge.

Can conscious awareness be ascertained from physiological responses alone? We evaluate a novel learning-based procedure permitting detection of conscious awareness without reliance on language comprehension or behavioural responses. The method exploits a situation whereby only consciously detected violations of an expectation alter skin conductance responses . Thirty participants listened to sequences of piano notes that, without their being told, predicted a pleasant fanfare or an aversive noise according to an abstract rule. Stimuli were presented without distraction , or while distracted (...) by a visual task to remove awareness of the rule . A test phase included occasional violations of the rule. Only participants attending the sounds reported awareness of violations and only they showed significantly greater SCR for noise occurring in violation, vs. accordance, with the rule. Our results establish theoretically significant dissociations between conscious and unconscious processing and furnish new opportunities for clinical assessment of residual consciousness in patient populations. (shrink)

v. 1. Vedas to the auxiliary scriptures -- v. 2. Three non-Vedic systems : Cārvāka, Jaina, and Buddha -- v. 4. Western impact on Indian thought.

The documented efficacy and long-term benefit of antidepressants in patients with recurrent forms of severe anxiety or depressive disorders support their use in those individuals with these disorders, who experience suicidal thoughts or behavior. In general, it is assumed that antidepressants are beneficial for all symptoms of depression, including suicidality. However, some evidence suggests that Selective Serotonin Reuptake Inhibitors [SSRIs] may cause worsening of suicidal ideas in vulnerable patients. Systematic reviews and pooled analysis of experimental, observational, and epidemiological studies have (...) investigated the use of SSRIs and their association with suicidality. Taking account of the methodological limitations of these studies, the current evidence fails to provide a clear relationship between their use and risk of suicidality in adults. However, in children and adolescents, there appears to be a bit of increased risk of suicidal ideations and attempts, but not of completed suicides. This risk can be anticipated and managed clinically. Clinicians are, therefore, advised to maintain a close follow-up during the initial treatment periods and remain vigilant of this risk. This advisory, however, should not deter clinicians from the use of effective dosages of antidepressants for a sufficient period of time, in every age group of patients, when clinically needed, and if found suitable otherwise. (shrink)

This paper presents an integralist approach to Jaina logic. This is built around an analysis of the pivotal notion of antarvyāpti in Jaina logic. It is shown in this connection why antarvyāpti needs to be considered the ‘Core Perspective/problem’ of Jaina logic. Next, it is shown how all the salient features of Jaina logic (as viewed from its language-oriented perspective and the epistemic perspective respectively) stand intimately related to the so-called core perspective. In the remaining sections of the paper topics (...) like relationship of the core perspective i) to various non-standard systems of logic [DL, FL, NMR etc.,], ii) to the four pillars and to the eight MPC’s of Jaina philosophy, iii) to some bluntly unimaginative ways of looking at Jaina logic [e.g., Ducko-Rabbitism], iv) to the scheme of classification of propositions in Jaina logic, v) to the resulting conceptual economies related to methodology, and especially to a unified theory of Hetvābhāsa and, finally, vi) to a re-assessment of Frege-Husserl discord in the light of the significance of Jñānātmakatā vs Vākyātmakatā in Jaina logic, etc., have been discussed. (shrink)