Consciousness and Neuroscience, Misc

A unifying theory of general anesthetic-induced unconsciousness must explain the common mechanism through which various anesthetic agents produce unconsciousness. Functional-brain-imaging data obtained from 11 volunteers during general anesthesia showed specific suppression of regional thalamic and midbrain reticular formation activity across two different commonly used volatile agents. These findings are discussed in relation to findings from sleep neurophysiology and the implications of this work for consciousness research. It is hypothesized that the essential common neurophysiologic mechanism underlying anesthetic-induced unconsciousness is, as with (...) sleep-induced unconsciousness, a hyperpolarization block of thalamocortical neurons. A model of anesthetic-induced unconsciousness is introduced to explain how the plethora of effects anesthetics have on cellular functioning ultimately all converge on a single neuroanatomic/neurophysiologic system, thus providing for a unitary physiologic theory of narcosis related to consciousness. (shrink)

In this paper a new model of mind is proposed, to do so, at first it was assumed that our physical world a new structure and the mind defined in this context. In this model, the planets are massive curvature of time-space continuum that has made a trapping physical reality that we are located within. Then the mind is defined as an hourglass structure with half bulb within the physical reality and half out of it. This model with attention to (...) figures perhaps might be able to explain some mental states and disorders. (shrink)

Should the philosophy of biology deal with organismic, or with molecular aspects , or with both ? We are, of course, not the first to appreciate the ...

In the last decade, careful studies of the living brain have opened the way for human consciousness to return to the heights it held before the behavioristic coup of 1913. This is illustrated by seven cases: the discovery of widespread brain activation during conscious perception; high levels of regional brain metabolism in the resting state of consciousness, dropping drastically in unconscious states; the brain correlates of inner speech; visual imagery; fringe consciousness; executive functions of the self; and volition. Other papers (...) in this issue expand on many of these points. . In the past, evidence based on subjective reports was often neglected . It is still true that brain evidence has greater credibility than subjective reports, no matter how reliable. What is new is increasing convergence between subjective experiences and brain observations. For that reason it is no longer rare to see the word 'consciousness' and 'subjectivity' in major science journals. No one so far has discovered a gulf dividing mind and brain. On the contrary, the new evidence supports the central role of consciousness as it was regarded over more than two millenia of written thought. In a sense this was predictable. Nature is full of unexpected convergences -- between fruit fly genes and the human body, between the arc of a tennis ball and the orbit of Mars, and between consciousness and the brain. These convergences show once again the remarkable unity of the observable universe. (shrink)

Conscious experience is one of the most difficult and thorny problems in psychological science. Its study has been neglected for many years, either because it was thought to be too difficult, or because the relevant evidence was thought to be poor. Bernard Baars suggests a way to specify empirical constraints on a theory of consciousness by contrasting well-established conscious phenomena - such as stimulus representations known to be attended, perceptual, and informative - with closely comparable unconscious ones - such as (...) stimulus representations known to be preperceptual, unattended, or habituated. Adducing data to show that consciousness is associated with a kind of global workplace in the nervous system, and that several brain structures are known to behave in accordance with his theory, Baars helps to clarify many difficult problems. (shrink)

Because it is unclear how a nonconscious stimulus is cognitively processed, there is uncertainty concerning variables that modulate the processing. In this context recent findings of a set of neuroimaging experiments are important. These findings suggest that conscious and nonconscious stimuli activate same areas of the brain during performance of a similar task. Further, different areas are activated when a task is performed with or without awareness of processing. It appears that the neural network involved in cognitive processing depends on (...) the awareness of processing rather than awareness of perception. Since conscious and nonconscious cognitive processing use separate neural networks, each processing is modulated by different variables. Attention modulates most conscious cognitive processing and most, but not all, nonconscious processing is attention dependent. Nonconscious tasks that require attentional resources, with or without conscious awareness, are processed using the attention dependent system. Further, because attention dependent and attention independent tasks are processed by separate neural networks, the cognitive processing and modulating variables can be understood better if cognitive tasks are defined as attention dependent or attention independent, rather than conscious or nonconscious. (shrink)

Unresponsive wakefulness syndrome (UWS, previously known as vegetative state) occurs after patients survive a severe brain injury. Patients suffering from UWS have lost awareness of themselves and of the external environment and do not retain any trace of their subjective experience. Current data demonstrate that neuronal functions subtending consciousness are not completely reset in UWS; however, they are reduced below the threshold required to experience consciousness. The critical factor that determines whether patients will recover consciousness is the distance of their (...) neuronal functions from this threshold level. Recovery of consciousness occurs through functional and/or structural changes in the brain, i.e., through neuronal plasticity. Although some of these changes may occur spontaneously, a growing body of evidence indicates that rehabilitative interventions can improve functional outcome by promoting adaptive functional and structural plasticity in the brain, especially if a comprehensive neurophysiological theory of consciousness is followed. In this review we will focus on the pathophysiological mechanisms involved in UWS and on the plastic changes operating on the recovery of consciousness. (shrink)

Block argues that relevant data in psychology and neuroscience shows that access consciousness is not constitutively necessary for phenomenality. However, a phenomenal state can be access conscious in two radically different ways. Its content can be access conscious, or its phenomenality can be access conscious. I’ll argue that while Block’s thesis is right when it is formulated in terms of the first notion of access consciousness, there is an alternative hypothesis about the relationship between phenomenality and access in terms of (...) the second notion that is not touched by Block’s argument. (shrink)

Any attempt to elucidate the nature and mechanism of passivity phenomena, i.e., experiences that one’s conscious actions or thoughts have not been ‘willed’ by oneself, requires an integrative philosophical–neurobiological approach. The model proposed here adopts some fundamental positions that have long been advocated by philosophers and theoretical psychologists and have now found support from functional neuroanatomy. First, we experience our actions not from the standpoint of the executive but through the perception of its effects. Second, the ‘self’ is not an (...) agent of behaviour. Third, behaviour is energised and integrated by basic drives . Fourth, the view that the experience of an acting self is related to drive reduction associated with voluntary actions is perhaps less well developed. The model thus proposes that passivity phenomena are actions that are induced by the perception of salient events but that are not integrated with or conducive to the overall motivational state of the organism. It has been suggested that, following the perception of salient events, competition arises between automatic response tendencies seeking expression. The prefrontal cortex appears to play an important role not only in determining which events are to be perceived but also which of the corresponding response dispositions is to be selected and actualised in overt behaviour. Thus, action selection is the outcome of competition between response tendencies in the context of prefrontal biasing signals that represent drives and strivings for goals. Action selection may be uncoupled from drives and strivings as a result of a lowering of the threshold for action selection—as is suggested to be the case in schizophrenic passivity phenomena—or due to disconnection from prefrontal regions—as may be the case in the alien limb syndrome. (shrink)

Current cognitive science models of perception and action assume that the objects that we move toward and perceive are represented as determinate in our experience of them. A proper phenomenology of perception and action, however, shows that we experience objects indeterminately when we are perceiving them or moving toward them. This indeterminacy, as it relates to simple movement and perception, is captured in the proposed phenomenologically based recurrent network models of brain function. These models provide a possible foundation from which (...) predicative structures may arise as an emergent phenomenon without the positing of a representing subject. These models go some way in addressing the dual constraints of phenomenological accuracy and neurophysiological plausibility that ought to guide all projects devoted to discovering the physical basis of human experience. (shrink)

I here present some doubts about whether Mandik’s (2010) proposed intermediacy and recurrence constraints are necessary and sufficient for agentive experience. I also argue that in order to vindicate the conclusion that agentive experience is an exclusively perceptual phenomenon (Prinz, 2007), it is not enough to show that the predictions produced by forward models of planned motor actions are conveyed by mock sensory signals. Rather, it must also be shown that the outputs of “comparator” mechanisms that compare these predictions against (...) actual sensory feedback are also coded in a perceptual representational format. (shrink)

The purpose of this paper is to defend what I call the action-oriented coding theory (ACT) of spatially contentful visual experience. Integral to ACT is the view that conscious visual experience and visually guided action make use of a common subject-relative or 'egocentric' frame of reference. Proponents of the influential two visual systems hypothesis (TVSH), however, have maintained on empirical grounds that this view is false (Milner & Goodale, 1995/2006; Clark, 1999; 2001; Campbell, 2002; Jacob & Jeannerod, 2003; Goodale & (...) Milner, 2004). One main source of evidence for TVSH comes from behavioral studies of the comparative effects of size-contrast illusions on visual awareness and visuo- motor action. This paper shows that not only is the evidence from illusion studies inconclusive, there is a better, ACT-friendly interpretation of the evidence that avoids serious theoretical difficulties faced by TVSH. (shrink)

The papers in this special issue are all descended from papers presented at the second Online Consciousness Conference. I founded the Online Consciousness Conference at Consciousness Online (http://consciousnessonline.wordpress.com) in 2008 mostly because no one else would. Being inspired by the Online Philosophy Conference, I mentioned to several people that it would be great if we had something like that in Consciousness Studies. People I talked to were very enthusiastic but no one seemed like they wanted to initiate the process. I (...) figured I would give it a shot and have been pleasantly surprised by the results. Papers from the first conference were published in a special issue of the Journal of Consciousness Studies, papers from the second are in this special issue, and papers from the third conference (2011) are due to come out as a book in Springer’s series Studies in Brain and Mind. As I write this I am planning the fourth conference for February 2012. There is no way I could have known back in 2008 how well the conference would be received but I am grateful for that reception. (shrink)

In "The Cerebral Code," he has solidly embedded his ideas in experimental neurophysiology and neuropharmacology, deriving from his decades in the laboratory.

We argue that Graziano and Kastner are mistaken to claim that neglect favors their self-directed social perception account of consciousness. For the latter should not predict that neglect would result from damage to mechanisms of social perception. Neglect is better explained in terms of damage to attentional mechanisms.

In this chapter, I propose the mechanism of cognitive enhancement based on studies of cognitive-enhancing drugs and behavioral training. I argue that there are mechanistic differences between cognitive-enhancing drugs and behavioral training due to their different enhancing effects. I also suggest possible mechanisms for cognitive-enhancing drugs and behavioral training and for the synergistic effects of their simultaneous application.

To what extent is imagination dependent on embodied experience? In attempting to answer such questions I consider the experiences of those who have to come to terms with altered neurological function, namely those with spinal cord injury at the neck. These people have each lost all sensation and movement below the neck. How might these new ways of living affect their imagination?

The notion of loop seems to be ubiquitous in the study of organisms, the human mind and symbolic systems. With the possible exception of quantum-mechanical approaches, the treatments of consciousness we are acquainted with crucially appeal to the concept of loop. The uses of loops in this context fall within two broad classes. In the first one, loops are used to express the control of the organism’s interaction with the environment; in the second one, they are used to express self-reference. (...) Both classes are tied with investigations which aim at accounting for symbolic capabilities, and ultimately for subjectivity. Neurophysiological research detects loops in the animal nervous system since its very inception (e.g., all the work on the reflex arc). Recently, Gray proposed a model purporting to explain the mechanism supporting the contents of consciousness in the human CNS, in ways that are practically indistinguishable from models formulated within the cybernetical point of view. Both types of models apply loops in strikingly similar ways. While there is no conclusive evidence that loops are necessary to support consciousness, they are nonetheless as good a candidate as today can be found for inclusion in the list of essential ingredients for subjectivity to arise. In the first two sections we discuss the above mentioned uses by means of significant examples. In the third section, we compare Gray’s recent model to MacKay’s early cybernetical model of a selfobserving system, in the setting of a broader discussion on loops for consciousness. (shrink)

cal basis of consciousness. We continue by discussing the relation between spatiotem- One of the outstanding problems in the cog- poral patterns of brain activity and con- nitive sciences is to understand how ongo- sciousness, with particular attention to pro- ing conscious experience is related to the cesses in the gamma frequency band. We workings of the brain and nervous system. then adopt a critical perspective and high-.

[opening paragraph] -- Clark: The `astonishing hypothesis' which you put forward in your book, and which you obviously feel is very controversial, is that `You, your joys and sorrows, your memories and ambitions, your sense of personal identity and free will are, in fact, no more than the behaviour of a vast assembly of nerve cells. As Lewis Carroll's Alice might have phrased it: `You're nothing but a pack of neurons'.' But it seems to me that this is not so (...) astonishing a statement for a scientist to make. Isn't this what reductionist science has always believed? (shrink)

The component structures of two distinct neuropsychological systems are described. "System-Y" depends upon "system-X" which, on the other hand, can operate independently of system-Y. System-X provides a matrix upon which system-Y must operate, and, system-Y is transformed by the operations of system-X. In addition these neuropsychological structures reverberate in political history and in the cosmos. The most fundamental structure in the soul, in society, and in the cosmos, has the form of a conical spiral. It can be described mathematically as (...) an harmonic system and mythologically in terms of the birth, marriage and death of the divine-king. ;System-Y corresponds to the neocortex. System-X corresponds to the region below the cortex including the limbic brain. Many of the essential structures of system-Y are captured by Plato's image of the helmsman: orientation, locomotion, manual control and dexterity, visual guidance, verbal command, intention, and volition. System-X on the other hand has been systematically neglected by Western culture, beginning with Plato. ;The dissertation builds upon Yakovlev's distinction between "teleokinesis," "ectokinesis" and "endokinesis." "Teleokinesis" refers to goal-directed action in external space, and belongs to system-Y. Ectokinesis and endokinesis are components of system-X. "Endokinesis" refers to movements within the body. "Ectokinesis" refers to the emotions, which are expressions of endokinesis. The mechanics of ectokinesis is that of an harmonic or vibrational system, as is the mechanics of a musical instrument. ;Within a trance the structure of system-Y is temporarily altered, such that system-X enters the foreground of awareness. Because ectokinesis is analogous to music cultures inspired by trance experience understand the universe in terms of music. The structure of ectokinesis in a trance is that of a conical spiral. Plato inherited the mystical traditions of the ancient Near East but replaced the spiral of emotions with a spiral of ideas , by understanding the axis of the cone as the paradigmatic dimension, and the angular rotation of the spiral as the syntagmatic dimension, of language. Finally I explain how the mythology and political structure of theocratic society imitated the neuropsychological structures of trance experience. (shrink)

This book investigates the philosophical, empirical, and theoretical bases on which a cognitive neuroscience of consciousness can be founded.