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PubMed1997

The self in self-conscious emotions.

The study of self-conscious emotions has only recently begun. The model outlined here offers an opportunity to consider and to define carefully some of the self-conscious emotions. Unless we develop a more accurate taxonomy, we will be unable to proceed in our study of these emotions. Given the renewed interest in emotional life, it is now appropriate to consider these more complex emotions rather than the more "primary" or "basic" ones. Moreover, as others have pointed out, these self-conscious emotions are intimately connected with other emotions, such as anger and sadness (see for example, H.B. Lewis, 1971; Lewis, 1992b; Morrison, 1989). Finally, given the place of self-evaluation in adult life, it seems clear that the self-conscious evaluative emotions are likely to stand in the center of our emotional life (Dweck & Leggett, 1988; Heckhausen, 1984).

Awareness↗

PubMedDate not supplied

Ask the expert: conscious sedation.

The case study illustrates safe use of conscious sedation and careful attention to prevention of complications as outlined in the AAP and ASA practice guidelines. Before implementation of a conscious sedation program, care providers need to have a clear idea of the goals of conscious sedation. These goals, as described by the American Academy of Pediatrics (1992) are: "1) to guard the patient's safety and welfare; 2) to minimize physical discomfort or pain; 3) to minimize negative psychologic responses to treatment by providing analgesia and to maximize the potential for amnesia; 4) to control behavior; and 5) to return the patient to a state in which safe discharge, as determined by recognized criteria, is possible" (p. 1,110). With careful attention to these goals, conscious sedation can be a valuable adjunct to pediatric care.

Child↗

PubMed1997

Aortic peak flow velocity as an index of myocardial contractility in the conscious rat.

The present studies were conducted in conscious, instrumented rats to evaluate measurements of aortic peak flow velocity (PFV) as an index of myocardial contractility. Because our previous studies had characterized/verified procedures to determine pressure-derived indices of contractile function in the anesthetized, ventilated, open-chest rat, we first correlated PFV with (a) maximum rate of left ventricular pressure development (max +dP/dt) and (b) a contractility index derived by dividing max +dP/dt by left ventricular pressure at max +dP/dt [(dP/dt)/P] in anesthetized rats (n = 5). The positive inotropic agent, isoproterenol, given by bolus intravenous injection (0.2 microgram), significantly and concurrently increased dP/dt, (dP/dt)/P, and PFV. The negative inotropic agent, propranolol, given by bolus intravenous injection (2 mg/kg), significantly and concurrently attenuated all of the above measurements. When control, isoproterenol, and propranolol responses were used to calculate multivariate correlation coefficients among dP/dt, (dP/dt)/P, and PFV, r values ranged from 0.74 (PFV vs. dP/dt) to 0.84 (dP/dt vs. (dP/dt)/P) to 0.91 (PFV vs. (dP/dt)/P). A separate group of rats (n = 4) was surgically implanted with ascending aortic blood flow sensors, carotid artery and jugular vein catheters. Intravenous isoproterenol (0.2 microgram, bolus) elicited increased cardiac (heart rate and cardiac output) and decreased peripheral vascular resistance (mean arterial blood pressure) beta-adrenergic receptor agonist effects. Propranolol (2 mg/kg, i.v. bolus) produced hemodynamic effects consistent with cardiovascular beta-adrenergic receptor blockade. Isoproterenol and propranolol had directionally appropriate, and significant effects on PFV in the conscious rat. When compared with PFV values under control conditions in the anesthetized rat, conscious rat values are approximately double those observed under anesthesia; however, the relative PFV responses to isoproterenol and propranolol were not affected. Therefore, the present studies provide evidence that aortic PFV can be utilized as an estimate of heart contractile performance, i.e., myocardial contractility, in the conscious, instrumented rat.

Adrenergic beta-Agonists↗

PubMed1981

Evaluation of disturbances of consciousness.

Consciousness as the highest form of neuronal activity is very difficult to define. It is superior to unconditioned reflex activity and vigilance, and its most important sign is verbal signalization. Therefore, a scheme of evaluation of impaired consciousness was elaborated by the author, in which in the first group a strong painful impulse is the stimulus, in the second group of consciousness proper the word is the stimulus. This simple scheme of 8 points can be applied also by nurses.

Cognition Disorders↗

PubMed1975

The concepts: Disturbed state of consciousness and psychosis.

A theoretical analysis is made of the two concepts: "disturbed state of consciousness" (DSC) and "psychosis", and these concepts are defined in ways which are consistent with actual clinical psychiatric work on the Continent. Concerning DSC's two points are emphasized: Whether we, as psychiatrists, are conscious of it or not--one of our premisses for classifying a state as a pathological DSC is an evaluation of the client's ability to change the state voluntarily. Furthermore, stating that a DSC was present in the time interval tl0tn implies stating that all experiences were abnormal in some way during the interval--when the word "experience" is taken in the broad sense, including William James' "fringe" and "embeddedness" in the stream of consciousness. Reality testing may remain the cardinal point in the definition of "psychosis"--if we make the distinction between theoretical, "fullblown", syndromes and concrete syndromes with fewer symptoms clear to ourselves.

Alcoholic Intoxication↗

PubMed1976

Brain circuits for consciousness.

The question is explored of the location of consciousness in the human brain. The author's own studies of defects of consciousness as the result of the splitting of the corpus callosum are described and disorders of consciousness associated with damage to other specific areas of the brain, are reviewed. A circuit spanning the brain is described which stretches from the parietal lobe at one side to the parietal lobe at the other and includes the splenium of the corpus callosum. The medial banks of the hemispheres, the callosal as well as the cingulate areas, are also thought to be involved.

Brain Mapping↗

PubMed1999

Comparison of evoked cortical activity in conscious and propofol-anesthetized rats using functional MRI.

Changes in cortical activity during foot shock were assessed under conscious and propofol-anesthetized conditions using functional magnetic resonance imaging (fMRI). Increases in signal intensity were observed in the contralateral somatosensory cortex in response to electrical shock of the hindpaw under both conditions. These increases in cortical signal ranged from 6% to 26% while awake and from 1% to 6% under propofol anesthesia. In each of the six animals studied, the largest increase in blood oxygenation level-dependent (BOLD)-based signal intensity was observed during consciousness. In three of six animals, propofol anesthesia depressed signal intensity by as much as 10-fold, showing that the level of cortical activity during foot shock is dampened by anesthesia. These results indicate it would be advantageous to use fully conscious animals to maximize BOLD-based MRI signal in certain behavioral studies using MR spectrometers with modest field strengths (1.0-2.0 T).

Anesthesia, General↗

PubMed1979

Consciousness and the brain: evolutionary aspects.

Self-reflective consciousness is distinguished from 'simple' awareness and from conscious awareness. Awareness is a fundamental property of living matter as it reacts to environmental stimuli. A hypothesis is advanced to account for the general phenomenon of decussation of nerve fibres in the central nervous system of vertebrates. This feature, the crossing over of nerve fibres to the opposite side of the brain, is interpreted as exemplifying the inherent caution of living forms. The evolution of increasing complexity of structure in spinal cord and brain is a prerequisite for increasing awareness of the environment and for increasing freedom from its constraints. Conscious awareness is manifested in living forms primarily when they are learning to respond either to new stimuli or to internal demands such as breathing and walking. The relegation of learnt activities to the realm of unconscious reflex allows for concentration on new and more complex responses, which leads to further freedom of action. The seeming simplicity of human thinking rests on the increasing complexity of the evolving brain and of appropriate responses learnt during phylogenetic development. The human brain and its thinking functions are basically trustworthy because they are rooted in biological evolution.

Amoeba↗

PubMed2004

Mapping the time course of nonconscious and conscious perception of fear: an integration of central and peripheral measures.

Neuroimaging studies using backward masking suggest that conscious and nonconscious responses to complex signals of fear (facial expressions) occur via parallel cortical and subcortical circuits. Little is known, however, about the temporal differentiation of these responses. Psychophysics procedures were first used to determine objective thresholds for both nonconscious detection (face vs. blank screen) and discrimination (fear vs. neutral face) in a backward masking paradigm. Event-related potentials (ERPs) were then recorded (n = 20) using these thresholds. Ten blocks of masked fear and neutral faces were presented under each threshold condition. Simultaneously recorded skin conductance responses (SCRs) provided an independent index of stimulus perception. It was found that Fear stimuli evoked faster SCR rise times than did neutral stimuli across all conditions, indicating that emotional content influenced responses, regardless of awareness. In the first 400 msec of processing, ERPs dissociated the time course of conscious (enhanced N4 component) from nonconscious (enhanced N2 component) perception of fear, relative to neutral. Nonconscious detection of fear also elicited relatively faster P1 responses within 100 msec post-stimulus. The N2 may provide a temporal correlate of the initial sensory processing of salient facial configurations, which is enhanced when top-down cortical feedback is precluded. By contrast, the N4 may index the conscious integration of emotion stimuli in working memory, subserved by greater cortical engagement. Hum. Brain Mapping 21:64-74, 2004.

Adolescent↗

PubMed2005

The therapeutic effects of the free-associative state of consciousness.

Free association is therapeutically helpful in the regulation of states of consciousness. A person who free-associates enters a particular state of consciousness characterized by increased subjective self-awareness and disregard for reality, together with implicit pulls for objective self-awareness and reality adherence. Free association facilitates the patient's learning to integrate and to shift flexibly among points on these dimensions. Tensions existing in the free-associative state are embedded in a similar tension between free associating and reacting to the analyst's interventions, so interplay between free association and intervention also facilitates regulation of states of consciousness.

Adult↗

PubMed2003

Supraspinal N-methyl-D-aspartate receptor inhibition influences the micturition reflex and function of the upper urinary tract of anesthetized and conscious rats.

AIMS: To examine the effects of N-methyl-D-aspartate (NMDA) receptor antagonists on the frequency/volume (F/V) characteristics of micturition of conscious and anesthetized rats in relation to the mechanisms of renal urine output and pyelo-ureteral transport function of the upper urinary tract. METHODS: Micturition F/V characteristics of 24 conscious female Sprague-Dawley rats, each weighting 160-180 g, were evaluated in a metabolic chamber. Control values of (F/V) were first obtained after administration of a 5-mL loading dose of saline solution and compared with intraperitoneal (i.p.) injection of 0.3-6.0 mg/kg of LY274614 (LY) and 0.3-40 mg/kg of dextromethorphan (DEX). Upper urinary tract studies were performed on two groups of urethane anesthetized rats (1.2 g/kg, s.c.). A group of 17 rats was used for intravenous (i.v.) injection of 1-30 mg/kg of LY and 1-10 mg/kg of DEX. In a second group of 12 rats, 0.2 mg/kg of LY and DEX were administered intracerebroventricularly (i.c.v.), by placing a catheter into the third ventricle. In anesthetized rats, continuous cystometrograms (CMG) were done while perfusing the renal pelvis with indigo carmine, and measuring pelvic and arterial pressure and as well as visualizing the transport of urine within the upper urinary tract by using videomicroscopic imaging. RESULTS: In conscious rats, the i.p. injection of LY and DEX produced a significant and dose-dependent increase in functional bladder capacity and a considerable increase in diuresis. In anesthetized rats, i.v. and i.c.v. administration of LY and DEX affected the micturition reflex, reflected as a significant increase in bladder capacity and preleakage pressure. Videomicroscopic imaging shows dilation of the ureter and a dilution of the dyed urine after the i.v. and i.c.v. injection of LY and DEX. The frequency of ureteral peristalsis and renal pelvic contractions were significantly decreased after i.v. and i.c.v. injection of LY as well as DEX. CONCLUSIONS: The present study shows that the NMDA receptor antagonists LY and DEX given systemically (i.v. and i.p.) or intracerebroventricularly influence the micturition reflex and modulate pyelo-ureteral motility as well as the rate of urine production. From the present study, it is suggested that NMDA receptors are directly involved in regulating pyelo-ureteral peristalsis as well as in the coordination of urine transport between upper and lower urinary tract.

Anesthesia↗

PubMed1997

Level of consciousness and memory during the intracarotid sodium amobarbital procedure.

Controversy exists regarding differential effects on consciousness of left/right cerebral inactivation via intracarotid amobarbital. Further, the effects of level of consciousness (LOC) on memory during the intracarotid sodium amobarbital procedure (IAP) are unclear. A modified version of the Glasgow Coma Scale altered to avoid the confounding effects of aphasia was employed to assess LOC in 97 patients during the IAP. A greater impairment in LOC occurred with left cerebral inactivation. Memory was more impaired following left hemisphere injections as well as from injections contralateral to seizure focus. Memory was correlated with LOC, and this effect was more prominent for right hemisphere injections and for injections ipsilateral to seizure focus. These findings support differential cerebral roles in consciousness and demonstrate that IAP memory performance may be affected by the patient's LOC.

Adolescent↗

PubMed1993

The problem of consciousness.

This paper attempts to begin to answer four questions. (1) What is consciousness? (2) What is the relation of consciousness to the brain? (3) What are some of the features that an empirical theory of consciousness should try to explain? (4) What are some common mistakes to avoid?

Brain↗

PubMed1995

Thalamic contributions to attention and consciousness.

A tacit assumption since the 19th Century has been that the neocortex serves as the "seat of consciousness." An unexpected challenge to that assumption arose in 1949 with the discovery that high-frequency EEG activation associated with an alert state requires the intactness of the brainstem reticular formation. This discovery became the impetus for nearly three decades of research on what came to be known as the reticular activating system. By the 1970s, however, methodological and philosophical controversies led to the general abandonment of subcortical theories of attention and consciousness, with a return to an almost exclusive focus upon the cortex. With recent advances in the neurosciences the focus is shifting once more, this time to the unique contributions of cortical, thalamic, and brainstem structures in mediating selective attention and perceptual awareness. This paper offers a nontechnical review of the history of these developments up to contemporary interest in the putative role of oscillatory EEG patterns in the integration of perceptual features of experience. It puts forward the thesis that a key to understanding attention and consciousness is an appreciation of the contributions of the thalamus to these cognitive processes.

Animals↗

PubMed1995

The sketchpad model. A theory of consciousness, perception, and imagery.

Subjective consciousness suggests a unity of the sensing and perceiving self that is difficult to reconcile with the multiplicity of sensory analyzers and the absence of a convergence zone in the brain. This has led--on the one hand--to the dead-end assumption of a unifying sentient homunculus and--on the other--to a denial of conscious unity. The sketchpad model presented here avoids this dilemma by viewing conscious thought as a selfreferent loop of neural activity, rather than as the information content of a fictitious set of output neurons. Use is made of the numerous neural pathways that originate at various cortical and subcortical areas and terminate in the thalamus. The model assumes that primary sensory inputs are modified by such feedback in the thalamic relay nuclei through hill-climbing processes that tend to optimize global responses.

Arousal↗

PubMed1999

The link between brain learning, attention, and consciousness.

The processes whereby our brains continue to learn about a changing world in a stable fashion throughout life are proposed to lead to conscious experiences. These processes include the learning of top-down expectations, the matching of these expectations against bottom-up data, the focusing of attention upon the expected clusters of information, and the development of resonant states between bottom-up and top-down processes as they reach an attentive consensus between what is expected and what is there in the outside world. It is suggested that all conscious states in the brain are resonant states and that these resonant states trigger learning of sensory and cognitive representations. The models which summarize these concepts are therefore called Adaptive Resonance Theory, or ART, models. Psychophysical and neurobiological data in support of ART are presented from early vision, visual object recognition, auditory streaming, variable-rate speech perception, somatosensory perception, and cognitive-emotional interactions, among others. It is noted that ART mechanisms seem to be operative at all levels of the visual system, and it is proposed how these mechanisms are realized by known laminar circuits of visual cortex. It is predicted that the same circuit realization of ART mechanisms will be found in the laminar circuits of all sensory and cognitive neocortex. Concepts and data are summarized concerning how some visual percepts may be visibly, or modally, perceived, whereas amodal percepts may be consciously recognized even though they are perceptually invisible. It is also suggested that sensory and cognitive processing in the What processing stream of the brain obey top-down matching and learning laws that are often complementary to those used for spatial and motor processing in the brain's Where processing stream. This enables our sensory and cognitive representations to maintain their stability as we learn more about the world, while allowing spatial and motor representations to forget learned maps and gains that are no longer appropriate as our bodies develop and grow from infanthood to adulthood. Procedural memories are proposed to be unconscious because the inhibitory matching process that supports these spatial and motor processes cannot lead to resonance.

Attention↗

PubMed1999

A passion of the soul: an introduction to pain for consciousness researchers.

Pain is an important focus for consciousness research because it is an avenue for exploring somatic awareness, emotion, and the genesis of subjectivity. In principle, pain is awareness of tissue trauma, but pain can occur in the absence of identifiable injury, and sometimes substantive tissue injury produces no pain. The purpose of this paper is to help bridge pain research and consciousness studies. It reviews the basic sensory neurophysiology associated with tissue injury, including transduction, transmission, modulation, and central representation. In addition, it highlights the central mechanisms for the emotional aspects of pain, demonstrating the physiological link between tissue trauma and mechanisms of emotional arousal. Finally, we discuss several current issues in the field of pain research that bear on central issues in consciousness studies, such as sickness and sense of self.

Consciousness↗

PubMed2000

A neurofunctional theory of visual consciousness.

This paper develops an empirically motivated theory of visual consciousness. It begins by outlining neuropsychological support for Jackendoff's (1987) hypothesis that visual consciousness involves mental representations at an intermediate level of processing. It then supplements that hypothesis with the further requirement that attention, which can come under the direction of high level representations, is also necessary for consciousness. The resulting theory is shown to have a number of philosophical consequences. If correct, higher-order thought accounts, the multiple drafts account, and the widely held belief that sensation precedes perception will all be found wanting. The theory will also be used to illustrate and defend a methodology that fills the gulf between functionalists who ignore the brain and neural reductionists who repudiate functionalism.

Attention↗