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PubMed1994

Consciousness and psychotherapy.

The origins and resistance to change of neurotic procedures are considered with particular reference to the nature and role of consciousness. It is argued that the traditional opposition between conscious and unconscious systems provides an unsatisfactory model. The crucial role of language in the formation of human self-consciousness is emphasized. The restricted procedural repertoire of neurotic subjects, and their deficient self-consciousness, can be attributed to a number of factors. It is argued that the main use of consciousness in therapy should be to heighten the patient's awareness of his or her damaging or restricting procedural repertoire through the process of reformulation, which allows recognition, and in due course revision to be achieved.

Anxiety Disorders↗
PubMed1983

Furosemide fails to alter plasma active or inactive renin in conscious sheep but does so in anaesthetized animals.

Regulation of plasma levels of active and inactive renin was investigated using sheep with indwelling artery, vein and bladder catheters. Control and experimental studies were carried out in the same animals on different days. Volume depletion during any single experiment was limited to a maximum of 50 ml. Despite large changes in sodium and water excretion, the diuretic furosemide at two dose levels, 1 and 10 mg/kg, failed to alter plasma levels of either active or inactive renin in conscious sheep. Induction of pentobarbitone anaesthesia in the sheep did not, per se, alter either plasma active or inactive renin. Furosemide (10 mg/kg) in anaesthetized animals produced a similar diuresis and natriuresis response to conscious sheep, but plasma active renin increased by 270% and inactive renin decreased to zero. In conscious sheep given an infusion of papaverine, furosemide also produced an increase in plasma active renin and a concurrent decrease in the inactive form. In both anaesthetized animals and in conscious sheep infused with papaverine, furosemide-induced intrarenal vasodilation, as evidenced by changes in clearance of p-aminohippuric acid, was much reduced in comparison to the conscious animals. This may be significant in relation to the control of renin secretion. It appears that the macula densa sodium receptor, which is considered to regulate renin release, will only function after it has been primed by other intra- or extrarenal factors. This is discussed, particularly in relation to the possible role played by the prostaglandin system.

Anesthesia, Intravenous↗
PubMed1985

Fasting induces denervation natriuresis in the conscious rat.

The participation of renal nerves in the regulation of sodium excretion was studied in fed and overnight-fasted rats subjected to acute or chronic left kidney denervation or sham operation. Clearance experiments were performed on conscious restrained animals. Urine flow, glomerular filtration rate (GFR), and urinary sodium excretion were not different in left and right kidneys of sham-operated rats. In fed conscious rats, urine flow, GFR, and urinary sodium excretion of innervated (I) and denervated (D) kidneys were similar. In fasted conscious rats, significant denervation natriuresis was observed after both acute (I, 1.06 +/- 0.27; D, 1.56 +/- 0.40 mumol . min-1 . g-1, P less than 0.05) and chronic (I, 1.55 +/- 0.19; D, 2.20 +/- 0.18 mumol . min-1 . g-1, P less than 0.01) renal sympathectomy, whereas urine flow and GFR in I and D kidneys were not different. Additional experiments revealed that extracellular fluid and plasma volumes of fasted rats were decreased by approximately 10% compared with those of fed animals due to a significant overnight natriuresis and negative water balance. In fed conscious rats, the renal nerves do not seem to participate in the regulation of sodium excretion. The presence of denervation natriuresis in conscious fasted rats suggests that renal nerves are involved in sodium conservation during fasting to maintain extracellular fluid and plasma volume.

Animals↗
PubMed2003

Posterior segment ocular pharmacokinetics using microdialysis in a conscious rabbit model.

PURPOSE: To develop and establish a conscious rabbit model for ocular pharmacokinetic studies and to delineate the effects of anesthesia and probe implantation on the ocular disposition of ganciclovir. METHODS: A conscious rabbit model was developed for microdialysis of the posterior ocular segment. Rabbits were divided into three groups. Group I consisted of rabbits with no recovery period after probe implantation and were anesthetized throughout the experiment. Group II consisted of rabbits that had a more than 5-day recovery period and were conscious during the experiment. Group III consisted of rabbits that had a more than 5-day recovery period and were anesthetized during the experiment. (3)[H] ganciclovir was administered (50 microL) intravitreously in all groups, and ocular levels were determined for 10 hours at appropriate time intervals. Data obtained were subjected to noncompartmental modeling. RESULTS: Probe calibration studies indicated that the probes were functional for at least 14 days. The anesthetized groups, regardless of the period of recovery from probe implantation, exhibited higher areas under the curve than did the conscious group. The vitreous half-life of ganciclovir was significantly shorter in the groups with a recovery period of more than 5 days compared with the group with no recovery period. CONCLUSIONS: The conscious rabbit model was developed and can be used for a period of at least 14 days. Anesthesia increased ocular bioavailability of intravitreously administered ganciclovir, whereas probe implantation led to increased protein efflux into the vitreous, which may be the reason for the increased half-life of ganciclovir in group I.

Anesthetics, Dissociative↗
PubMed1995

Impairment of recognition memory with, but not without, conscious recollection in schizophrenia.

OBJECTIVE: To test the hypothesis that there is a link between the memory deficit associated with schizophrenia and an impairment of consciousness, an experiential approach was used to assess recognition memory and awareness in schizophrenic patients and normal subjects. METHOD: On a recognition memory task with low- and high-frequency words, the schizophrenic (N = 30) and normal (N = 30) subjects gave "remember" responses to recognized items that were accompanied by conscious recollection and "know" responses to items that were recognized on the basis of familiarity without any recollective experience. RESULTS: Schizophrenia selectively impaired recognition based on recollective experience, as measured by "remember" responses, but had no effects on "know" responses. In the comparison group, low-frequency words, relative to high-frequency words, enhanced conscious recollection but not familiarity. The schizophrenic patients did not display the same word-frequency effect. CONCLUSIONS: These results indicate that schizophrenia affects differentially two means of access to the personal past: it impairs recognition memory with, but not without, conscious recollection. They suggest that the impairment of conscious recollection observed in schizophrenic patients could be due to a failure of elaborative processing of information.

Adult↗
PubMed1994

Consciousness: function and definition.

The term "consciousness" plays an enormous role in the clinical assessment of patients and also in psychophysiological considerations. It has often been said that consciousness is a term that defies definition. This lack of definability, however, might be more apparent than real. In the multitude of facets, three main components can be singled out: a) vigilance, b) mental contents and c) selective attention. Vigilance, not to be equated with consciousness, is most amenable to electrophysiological studies. The stages of sleep have fairly well standardized EEG correlates, unlike the comatose states. The overflowing wealth of mental contents is constantly adjusted to momentary needs by the mechanism of selective attention. Awareness is a subcomponent and differs from both vigilance and consciousness. Emotionality is particularly important among the variety of further subcomponents. The time factor must be taken into account in order to understand the dynamics and fluctuations of consciousness.

Animals↗
PubMed2003

The emergence of consciousness and its role in human development.

In this paper, I talk about several issues in regard to self and consciousness. I do so from a developmental perspective, since such a perspective may provide a framework to help understand consciousness as seen in the adult human. Briefly, the two processes I will call the machinery of the self and the mental state of the idea of me develop over the first two years of the child's life. Moreover, and perhaps of equal importance is the fact that the development of consciousness (the idea of me) provides the scaffolding for the development of the child's social and emotional development and is the first step in the child's development of other mental states, which provide the underpinning of a theory of mind. I will first explore what a self is and what it is not; then I will present a developmental model that provides a way of measuring early the idea of me or consciousness. Having shown how to measure this mental state, I will show how it has an impact on the development of a theory of mind, as well as on the child's emotional and social life. Finally, I will turn to the emergence of explicit and implicit consciousness.

Consciousness↗
PubMed2006

Integrating the science of consciousness and anesthesia.

The nature and mechanism of human consciousness is emerging as one of the most important scientific and philosophical questions of the 21st century. Disregarded as a subject of serious inquiry throughout most of the 20th century, it has now regained legitimacy as a scientific endeavor. The investigation of consciousness and the mechanisms of general anesthesia have begun to converge. In the present article I provide an introduction to the study of consciousness, describe the neural correlates of consciousness that may be targets of general anesthetics, and suggest an integrated approach to the science of consciousness and anesthesia.

Anesthesia, General↗
PubMed2005

Early neural correlates of conscious somatosensory perception.

The cortical processing of consciously perceived and unperceived somatosensory stimuli is thought to be identical during the first 100-120 ms after stimulus onset. Thereafter, the electrophysiological correlates of conscious perception have been shown to be reflected in the N1 component of the evoked response as well as in later (>200 ms) nonstimulus-locked gamma-band (28-50 Hz) oscillatory activity. To evaluate more specifically the time course and correlation of neuronal oscillations with conscious perception, we recorded neuromagnetic responses to threshold-intensity somatosensory stimuli. We show here that cortical broadband activities phase locked to the subsequently perceived stimuli in somatosensory, frontal, and parietal regions as early as 30-70 ms from stimulus onset, whereas the phase locking to the unperceived stimuli was weak and primarily restricted to somatosensory regions. Such stimulus locking also preceded the perceived stimuli, indicating that the phase of ongoing cortical activities biases subsequent perception. Furthermore, the data show that the stimulus locking was present in the theta- (4-8 Hz), alpha- (8-14 Hz), beta- (14-28 Hz), and gamma- (28-40 Hz) frequency bands, of which the widespread alpha-band component was dominant for the consciously perceived stimuli but virtually unobservable for the unperceived stimuli. Our results show that the neural correlates of conscious perception are already found during the earliest stages of cortical processing from 30 to 150 ms after stimulus onset and suggest that alpha-frequency-band oscillations have a role in the neural mechanisms of sensory awareness.

Adult↗
PubMed2001

Cardiovascular and respiratory responses to microinjection of L-glutamate into the caudal pressor area in conscious and anesthetized rats.

The role of the caudal pressor area (CPA) in the maintenance of vasomotor tonus in anesthetized and decerebrate animals has been clearly established. In conscious animals, however, the participation of CPA in the cardiovascular control remains to be fully elucidated. In the present study, unilateral L-glutamate (L-Glu) (10 and/or 20 nmol/70 nl) microinjection into CPA, in conscious male Wistar rats (250-280 g) caused a significant increase in mean arterial blood pressure (MAP; control: 112 +/- 1.9 mmHg; after 20 nmol L-Glu: 139 +/- 4.5 mmHg, N = 12, P<0.05) and respiratory rate (control: 81 +/- 3.5 breaths/min; after 10 nmol L-Glu: 92 +/- 3 breaths/min, P<0.05; after 20 nmol L-Glu: 104 +/- 5 breaths/min, N = 6, P<0.05). The subsequent anesthesia with urethane caused a significant increase in basal respiratory frequency (conscious: 81 +/- 3.5 breaths/min; under urethane: 107 +/- 1.3 breaths/min, N = 6, P<0.05). Anesthesia also significantly attenuated L-Glu-evoked pressor (conscious: DeltaMAP = +27 mmHg; anesthetized: DeltaMAP = +18 mmHg, P<0.05) and respiratory responses. These results suggest that glutamatergic receptors in the CPA are involved in cardiovascular and respiratory modulation in conscious rats.

Anesthetics, Intravenous↗
PubMed1998

Disturbance of consciousness associated with hypophosphatemia in a chronically alcoholic patient.

A 69-year-old man with chronic alcoholism was admitted to our hospital due to disturbance of consciousness and oliguria. Emergency laboratory examination revealed metabolic acidosis, hypoglycemia, hyponatremia, mild liver dysfunction, acute renal failure and rhabdomyolysis. After administration of fluids and nutrients and continuous hemodiafiltration, he recovered from all signs and symptoms except for disturbance of consciousness after 7 days. Since severe hypophosphatemia persisted, we administered adequate phosphates, and then his level of consciousness normalized. We discuss the relationships among alcohol abuse, hypophosphatemia and disturbance of consciousness, and recommend that hypophosphatemia be considered a potential cause of disturbance of consciousness in alcoholic patients.

Acidosis↗
PubMed1998

[Spinal subarachnoid hemorrhage presenting as disturbance of consciousness with severe hypoglycorrhachia].

We report the case of an 84-year-old woman with spinal subarachnoid hemorrhage who presented with disturbance of consciousness and nuchal stiffness, bloody cerebrospinal fluid and severe hypoglycorrhachia. Initially, it was difficult to determine whether this was a case of spinal subarachnoid hemorrhage, purulent meningitis, or hemorrhagic encephalitis, because of the nuchal stiffness, disturbance of consciousness and severe hypoglycorrhachia. It is known that intracranial subarachnoid hemorrhage is accompanied by mild hypoglycorrhachia, but descriptions of glucose levels in cerebrospinal fluid in cases of spinal subarachnoid hemorrhage are rare. This case suggests that both spinal subarachnoid hemorrhage and intracranial subarachnoid hemorrhage are associated with hypoglycorrhachia. Furthermore, spinal subarachnoid hemorrhage is frequently accompanied by disturbance of consciousness. Therefore, sudden back pain or lumbago might not be interpreted as indicators of spinal subarachnoid hemorrhage, because patients, particularly elderly patients, may lose consciousness. We emphasize that the possibility of spinal subarachnoid hemorrhage should be considered in patients with disturbance of consciousness or hypoglycorrhachia even if they do not complain of sudden back pain.

Aged↗
PubMed2001

Conscious and unconscious influences of memory for object location.

The process-dissociation procedure was used to investigate conscious and unconscious influences of memory for object location. In two experiments, subjects worked with drawings of household objects and rooms of a house depicted on a computer monitor to simulate placing objects in various locations. Memory for object locations was tested by having subjects search for those objects. A double dissociation was obtained between estimates of conscious and unconscious influences of memory computed from equations that assumed independence between these two influences: Age-related differences were found in the estimate of conscious influences, but not in the estimate of unconscious influences, whereas manipulation of habit strength affected the unconscious estimate, but not the conscious estimate. These results were closely fit by a multinomial model assuming independence between conscious and unconscious influences of memory.

Adolescent↗
PubMed1992

[Formation of grand coalition when consciousness of intragroup competition is activated].

The purpose was to explore conditions encouraging to form grand coalition, which leads a group to high solidarity with strong consciousness of intragroup competition. Subjects, 64 male undergraduates, were divided into 16 groups of four persons each. Experiment was carried out with 2 x 2 design of (consciousness of intergroup competition: strong vs. weak) (consciousness of intragroup competition: strong vs. weak). Results showed that strong competitive spirits against other groups produced facilitative effects on formation of grand coalition even when the consciousness of intragroup competition was strong, and the facilitative effects were strong even when consciousness of intragroup competition was weak. In addition, the necessary conditions for group members to form grand coalition under strong intragroup competition were discussed.

Adult↗
PubMed1999

[Consciousness as the highest integrative function of brain].

This study has attempted to show that consciousness (sense) can develop only in the living systems during natural evolution based on self-organization. While modelling the systems experimentally, it is impossible to reproduce consciousness phenomena. This fact points to the global differences in the principles of management of living systems as compared to the artificial ones. Due to the existence of various forms of consciousness (from the simplest forms, such as sensing, perception, and feeling to the most complicated ones, such as motivation and desire), the living organisms are capable to interpret the complex neurodynamics of the brain into a simple and functionally significant integral form for them. Owing to consciousness, the behavior of living systems at the highest level of evolution (a human being) becomes an indeterminate behavior with the clearly expressed position of will freedom; it is also important that through consciousness an individual can influence different physiological mechanisms of living organisms.

Animals↗
PubMed2000

[Consciousness and models of brain dynamics].

Consciousness is connected with attention, working memory and perception. The stream of consciousness contains only those elements that are present in the working memory. Neurophysiological correlates of conscious states are sought in form of synchronization processes based on 40 Hz oscillations needed to solve the binding problem. Alternative theories to solve or avoid the binding problem are presented. Correlates based on neural complexity index recently introduced by Tonioni and Edelman are especially promising. Theories of "activity bubbles" and of adaptive resonance explain many aspects of the conscious' experience phenomenology. Arguments supporting the idea that consciousness is a process of discrimination of continuous, non-symbolic representations appearing in small-capacity working memory are presented. These representations create resonant states with long-term memory traces, a process that cannot be captured by digital computer simulations.

Attention↗
PubMed2001

[Diagnosis and differential diagnosis of consciousness disorders from the psychiatric viewpoint].

Diagnosis and differential diagnosis of disturbance of consciousness are often difficult, especially when occurring in the course of psychiatric diseases. Apart from discord in defining the term of consciousness it is not always easy to distinguish between qualitative and quantitative alterations of the disorders. The performance of an exact interview and a thorough clinical examination allows an estimation of the degree of dimming of consciousness as well as the possible causes. Disorder of Consciousness is often found in patients carrying out substance abuse but also in the course of other psychiatric diseases such as depression, schizophrenia, personality disorders and dissociative disorders. This article is dealing with the clinical approach towards patients experiencing alterations or disturbances of consciousness and is also trying to communicate innovations in the field of psychiatric diagnostics.

Alcoholic Intoxication↗
PubMedDate not supplied

[In search for neurophysiological criteria of altered consciousness].

Neurophysiological approaches to brain mechanisms of consciousness are discussed. The concept of spatial synchronization of nervous processes developed by M.N. Livanov is applied to neurophysiological analysis of higher brain functions. However, the spatial synchronization of brain potentials is only a condition for information processing and does not represent it as such. This imposes restrictions on conclusions about the neural mechanisms of consciousness. It is more adequate to use the concept of spatial synchronization in views of consciousness as a psychophysiological level along with sub- and superconsciousness in three-level structure of mind according to P.V. Simonov. Forms of consciousness interaction with other levels concern the problem of altered consciousness and may be reflected in various patterns of spatial organization of brain potentials.

Cognition↗