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PubMed1999

Environmental worry: a concept to explain differences in environmentally conscious behaviour?

The purpose of the present study was to determine the validity of a scale for measuring environmental worry. The environmental worry scale was used in a study with employees at three medium-sized companies in East Germany who were exposed to environmental problems (N = 74). Additionally, questionnaires were used to investigate the influence of environmental worry on environmentally conscious behaviour. The assumption was that a higher amount of environmental worry would induce a more careful use of resources. Furthermore, it was investigated which predicting factors may determine environmentally conscious behaviour. Following the Theory of Reasoned Action, we assessed attitude towards the environment, social identity, social norms, and environmentally conscious behaviour as well as environmental worry. Environmentally conscious behaviour was investigated as relating to avoidance of creating waste, separation of waste, environmental protection activities, saving of resources and use of toxic substances. The structure of factors determining the anxiety scale was confirmed; however, sex or age seemed to have no effects. A higher level of education correlated to less environmental worry in a significant way. A correlation between environmental worry and environmentally conscious behaviour could not be proven. However, the relationship between environmental worry, attitudes towards the environment, and social norms was significant. Our data suggest that for a modification of environmentally conscious behaviour, measures aimed at changing the social norm are more successful than those aimed at changing individual attitudes. Moreover, increased environmental worry does not seem to increase environmentally friendly behaviour.

Adult↗
PubMed2004

[The use of conscious sedation versus general anesthesia in modern dentistry: rising ethical dilemmas].

Conscious sedation and general anesthesia have been in the use of the dental profession since the first half of the 19th century. Although seemingly appealing to use due to alleviation of pain and anxiety induced by the dental treatment, the alteration of consciousness level of dental patients is not without risk. Morbidity and mortality due to dental treatment performed under general anesthesia were investigated at the last decades of the 20th century. The mortality rates found in these investigations were surprisingly high comparing to researches of morbidity and mortality due to other medical procedures, performed under general anesthesia. Therefore, although general anesthesia is sometimes the only way to treat certain patients, maintaining strict indications for dental treatment under general anesthesia is necessary. Conscious sedation was found as a safer alternative for achieving a level of consciousness enabling dental treatment in those patients who are unable to receive treatment in normal dental clinic settings. We therefore believe that conscious sedation should be the golden standard for the treatment of those patients. The practicing of dentistry in patients who have need of dental treatment under special settings such as general anesthesia and sedation raises ethical dilemmas to the caregiver. The following review will summarize the available data on morbidity and mortality due to dental treatment given under general anesthesia and conscious sedation. The ethical questions arising from their practicing will be discussed and some answers shall be proposed.

Anesthesia, Dental↗
PubMed2005

Algorithm for evaluation and disposition of a single episode of loss of consciousness.

The presentation of a solitary episode of loss of consciousness in aviators presents a challenge to the aerospace physician, who has certain vital obligations to fulfill: to find the cause of loss of consciousness; to find the likely pathology; and to make a decision about fitness for flying duties. Evaluation of loss of consciousness focuses on three systems: the cardiovascular system; the central nervous system; and the mental functioning. If an abnormality is found in any of the three systems, specific evaluation and treatment is warranted. However, if no pathophysiology is found, aeromedical disposition of such a case is determined by three questions. Is it a case of syncope? If it is indeed syncope, is it vaso-vagal syncope (VVS) or something more sinister? If it is VVS, is it likely to recur in flight? VVS may be a one-time occurrence due to sudden cessation of blood supply to the brain and is the most common cause of loss of consciousness. Correct diagnosis of VVS, while a daunting task, can be made possible by proper attention to history, clinical examination, and relevant clinical investigations. Once diagnosed, a single episode of VVS is considered compatible with flying duties. Two cases of loss of consciousness in different settings have been presented to highlight the dilemmas faced by an aerospace physician. An algorithm for evaluation of cases with a solitary episode of loss of consciousness is also suggested.

Adult↗
PubMed1995

[Disorders of consciousness as a manifestation of neurologic disease].

Seventy-nine patients admitted in the neurological Intensive care unit because of severe disturbances of consciousness has been evaluated. Protocol based on previous experiences in evaluation of unconsciousness patients was used. Forty-four patients died and thirty-five survived. In 46 patients cause of illness was intracerebral hemorrhage. In 44 of them the cause of hemorrhage was arterial hypertension and in two of them rupture of a-v malformation. The majority of patients actually 41 of them showed hemispheral localization of intracerebral hematoma and five subtentorial. Pontien hemorrhages was found in three and cerebellar in two patients. In majority of 24 patients with hemispheral localization of intracerebral hematoma who showed progressive deterioration of consciousness the signs of descendent transtentorial herniation were found. The symptoms of uncal herniation were rare. In three patients with subtentorial localization of intracerebral hematoma who died signs of upward transtentorial herniation were observed. In 16 patients with ischemic cerebrovascular accident who showed disturbances of the consciousness at the admittance or soon after, nine patients died and seven survived. The cause of their condition were great hemispheral, smaller brain stem ischemic lesion, or deterioration of consciousness was related to the somatic illness. Patients with great ischemic lesions showed similar course of consciousness deterioration as it was observed in patients with hemispherical intracerebral hematomas with difference that biphasic course of illness characterized with temporary stagnation or even slight improvement of patients condition and than secondary progression of deterioration was seen only in patients with intracerebral hematoma, probably because of secondary ischemic complications. Ten patients were admitted because of subarachnoidal and two of them because of intraventricular hemorrhage. Six of them died and four survived. These patients has rupture of great sacular aneurysm with fast development of high intracranial pressure. In two of them the cause of death was rerupture of aneurysm. Stuporous patient with hemispheral neoplasm showed development of descendent transtentorial herniation which was stopped by anti oedematous and corticosteroid therapy. Comatose patient with brisk response on oculocephalic stimulation and normal papillary light reflexes was suspected on intoxication rather than structural brain lesion. He recovered by diuretics and forced rehydratation. After becoming conscious barbiturate intoxication was confirmed. Three patients were admitted in coma because of poisoning with CO, two patients died. Two patients admitted in epileptic status showed late diencephalic state of coma and they survived after anti epileptics and antioedematous treatment.

Alcoholic Intoxication↗
PubMed1997

Some Essential Differences between Consciousness and Attention, Perception, and Working Memory

When "divided attention" methods were discovered in the 1950s their implications for conscious experience were not widely appreciated. Yet when people process competing streams of sensory input they show both selective processes and clear contrasts between conscious and unconscious events. This paper suggests that the term "attention" may be best applied to the selection and maintenance of conscious contents and distinguished from consciousness itself. This is consistent with common usage. The operational criteria for selective attention, defined in this way, are entirely different from those used to assess consciousness. To illustrate the scientific usefulness of the distinction it is applied to Posner's (1994) brain model of visual attention. It seems that features that are often attributed to attention-like limited capacity-may more accurately be viewed as properties of consciousness.

Journal Article↗
PubMed1997

[Stochastic relations between conscious and automatic memory processes: an expansion of the process-dissociation procedure].

This paper presents an extension of the process dissociation procedure with wordstem completion, allowing the measurement of the stochastic relation between conscious and automatic processes. The conditional probabilities of conscious remembering with and without automatic processes can be determined. The determination of these conditional probabilities succeeds due to the extension of the process dissociation procedure by an indirect wordstem completion test, without referring to the usual assumptions of the dissociation paradigm. For the evaluation of this extended process dissociation procedure a multinomial model is presented which allows the distinction between voluntary and involuntary conscious memory. The model is applied to a study by ourselves and to an experiment published by Toth, Reingold, and Jacoby (1994). The results show that the assumptions of stochastic independence or redundancy as well as exclusivity of conscious and automatic processes are often violated. Two conscious processes with different probabilities of occurrence are found; voluntary and involuntary conscious memory processes.

Awareness↗
PubMed2005

Phenomenological aspects of consciousness--its disturbance in acute and chronic stages.

The meaning of a disturbance of consciousness is completely different in an acute as opposed to a chronic stage. In the acute stage, the grade of arousal is the most essential component in order to assess the changes of the level of intracranial pressure in neurosurgical emergency room. A new coma scale called Emergency Coma Scale has been proposed, which represents a combination of the Glasgow Coma Scale and the Japan Coma Scale. In the chronic stage, however, contents of consciousness or mental function deserve phenomenological and holistic investigations, keeping the difference between consciousness and mind in consideration, in order not only to treat and care for patients following cerebral injuries, stroke and mild cognitive impairment in aged people. We propose the difference in conception between consciousness and mind; that is, consciousness consists of psycho-sensory afferent system, mind of psycho-motor efferent and afferent system, and memory and language as liaison officers between them. This proposal would play a role to understand mental change in the natural aging processes, when memory and cognition are deteriorating gradually, but is still in evolution in the field of culture.

Acute Disease↗
PubMed2003

Functional neuroanatomy of altered states of consciousness: the transient hypofrontality hypothesis.

It is the central hypothesis of this paper that the mental states commonly referred to as altered states of consciousness are principally due to transient prefrontal cortex deregulation. Supportive evidence from psychological and neuroscientific studies of dreaming, endurance running, meditation, daydreaming, hypnosis, and various drug-induced states is presented and integrated. It is proposed that transient hypofrontality is the unifying feature of all altered states and that the phenomenological uniqueness of each state is the result of the differential viability of various frontal circuits. Using an evolutionary approach, consciousness is conceptualized as hierarchically ordered cognitive function. Higher-order structures perform increasingly integrative functions and thus contribute more sophisticated content. Although this implies a holistic approach to consciousness, such a functional hierarchy localizes the most sophisticated layers of consciousness in the zenithal higher-order structure: the prefrontal cortex. The hallmark of altered states of consciousness is the subtle modification of behavioral and cognitive functions that are typically ascribed to the prefrontal cortex. The theoretical framework presented yields a number of testable hypotheses.

Consciousness↗
PubMed2001

Conceptual dilemmas in evaluating individuals with severely impaired consciousness.

States of severely impaired consciousness (SIC) are characterized by cognitive and motor limitations. This case report describes a 45-year-old female with impaired consciousness who began to 'walk'. She initially presented to the hospital unresponsive and was subsequently diagnosed with metabolic encephalopathy due to severe hypoglycaemia. Traditional indices of consciousness indicated a low level of responsiveness; however, during physical therapy, she displayed reciprocal walking movements when lifted to a standing position by two therapists. Despite her ability to walk increased distances during and after neurorehabilitation, she was unable to consistently demonstrate responses indicative of higher levels of consciousness. This case illustrates the challenge of rating patients with limited behavioural repertoire using established measures of impaired consciousness.

Brain Diseases, Metabolic↗
PubMed2006

Preserved subliminal processing and impaired conscious access in schizophrenia.

BACKGROUND: Studies of visual backward masking have frequently revealed an elevated masking threshold in schizophrenia. This finding has frequently been interpreted as indicating a low-level visual deficit. However, more recent models suggest that masking may also involve late and higher-level integrative processes, while leaving intact early bottom-up visual processing. OBJECTIVE: To test the hypothesis that the backward-masking deficit in schizophrenia corresponds to a deficit in the late stages of conscious perception, whereas the subliminal processing of masked stimuli is fully preserved. DESIGN: Twenty-eight patients with schizophrenia and 28 normal control subjects performed 2 backward-masking experiments. We used Arabic digits as stimuli and varied quasi-continuously the interval with a subsequent mask, thus allowing us to progressively unmask the stimuli. We finely quantified their degree of visibility using objective and subjective measures to evaluate the threshold duration for access to consciousness. We also studied the priming effect caused by the variably masked numbers in a comparison task performed on a subsequently presented and highly visible target number. RESULTS: The threshold delay between the digit and mask necessary for the conscious perception of the masked stimulus was longer in patients compared with controls. This higher consciousness threshold in patients was confirmed by an objective and a subjective measure, and both measures were highly correlated for the patients and controls. However, subliminal priming of masked numbers was effective and identical in patients and controls. CONCLUSIONS: Access to conscious report of masked stimuli is impaired in schizophrenia, whereas fast bottom-up processing of the same stimuli, as assessed by subliminal priming, is preserved. These findings suggest a high-level origin of the masking deficit in schizophrenia, although they leave open for further research its exact relation to previously identified bottom-up visual processing abnormalities.

Adolescent↗
PubMed1993

Integrated cortical field model of consciousness.

The idea that there is a localized module or limited capacity mechanism in the brain that subserves consciousness is wrong. Awareness is a product of the activity of widely distributed neuronal assemblies that represent diverse aspects of experience. Central to a representation's entry into consciousness is its integration into the currently dominant pattern of central neuronal activity (dominant focus). A representation anywhere in the forebrain could on one occasion enter consciousness and on another remain outside it, depending on whether it is, perhaps by temporal coherence of discharge of cell assemblies, integrated into the dominant focus. There is no privileged locus or 'internal eye' for the benefit of which input is elaborated and toward which information must be transported. When a perceptual decision is made there need be no re-enactment ('filling in') of the appearance in question. Nor is there a 'finish line', the crossing of which determines the perceived sequence of events. Neuropsychological syndromes that involve unawareness of a perceptual domain illustrate the explanatory value of this integrated cortical field model of consciousness. Awareness cannot be conceptualized as separate from the neural activity of which it is the subjective concomitant. Being aware is what it is like to have a particular pattern of neuronal activity. To regard consciousness as arising from brain activity by some esoteric transformation is misconceived.

Awareness↗
PubMed1993

A reflexive science of consciousness.

Classical theories of consciousness make it difficult to see how it can be a subject of scientific study. In contrast to physical events, it seems to be private, subjective and viewable only from a subject's first-person perspective. But much of psychology does investigate conscious experience, which suggests that classical theories must be wrong. An alternative, 'reflexive' model is proposed in which the external phenomenal world is viewed as part of consciousness rather than apart from it. Observed events are 'public' only in the sense of 'private experience shared'. Scientific observations are 'objective' only in the sense of 'intersubjective'. Observed phenomena are 'repeatable' only in that they are sufficiently similar to be taken for 'tokens' of the same event 'type'. This closes the gap between physical and psychological phenomena. Studies of consciousness face methodological difficulties. An experimenter E and a subject S may have 'symmetrical access' to events in the outside world in so far as they perceive those events (from a third-person perspective) using similar exteroceptive systems; but their access to the subject's body, brain and experience is 'asymmetrical' (E's third-person perspective versus S's first-person perspective). In so far as E and S each have partial access to such events, their perspectives are complementary. Systematic investigation of experience requires merely that experiences are potentially shareable, intersubjective and repeatable. In this the conditions for a science of consciousness are no different to those for a science of physics.

Animals↗
PubMed1986

Blood flows in the maxillocarotid anastomoses and internal carotid artery of conscious dogs.

Although the external carotid artery is known to contribute to the cerebral blood flow in anesthetized dogs, quantitative information on the anastomoses and their role in conscious dogs is lacking. This study was carried out to determine blood flows in these anastomoses and the internal carotid artery, and also to examine the functional significance of the anastomoses in conscious dogs. Fifteen-micron radioactive microspheres were injected into common and external carotid arteries of four conscious dogs through chronically implanted catheters. Blood flows were determined by the reference sample method and by comparing microsphere distributions in the brain and the masseter muscle. Blood flows were estimated to be 140 +/- 32, 7.7 +/- 1.4, and 3.3 +/- 1.1 ml/minute (mean +/- SD) in the common carotid artery, internal carotid artery, and anastomoses on each side, respectively. Additional evidence indicated that the anastomotic flow so determined was primarily the flow in the anastomotic artery. Humoral responses to angiotensin II infusions were also studied in conscious dogs. External carotid angiotensin increased plasma 11-hydroxycorticosteroid concentration (used as an index of ACTH secretion) but did not increase plasma vasopressin concentration to the same extent as common carotid infusion. Therefore, the external carotid artery is functionally important in perfusing the brain in conscious dogs.

11-Hydroxycorticosteroids↗
PubMed1997

A possible role for cholinergic neurons of the basal forebrain and pontomesencephalon in consciousness.

Excitation at widely dispersed loci in the cerebral cortex may represent a neural correlate of consciousness. Accordingly, each unique combination of excited neurons would determine the content of a conscious moment. This conceptualization would be strengthened if we could identify what orchestrates the various combinations of excited neurons. In the present paper, cholinergic afferents to the cerebral cortex are hypothesized to enhance activity at specific cortical circuits and determine the content of a conscious moment by activating certain combinations of postsynaptic sites in select cortical modules. It is proposed that these selections are enabled by learning-related restructuring that simultaneously adjusts the cytoskeletal matrix at specific constellations of postsynaptic sites giving all a similar geometry. The underlying mechanism of conscious awareness hypothetically involves cholinergic mediation of linkages between microtubules and microtubule-associated protein-2 (MAP-2). The first reason for proposing this mechanism is that previous studies indicate cognitive-related changes in MAP-2 occur in cholinoceptive cells within discrete cortical modules. These cortical modules are found throughout the cerebral cortex, measure 1-2 mm2, and contain approximately 10(3)-10(4) cholinoceptive cells that are enriched with MAP-2. The subsectors of the hippocampus may function similarly to cortical modules. The second reason for proposing the current mechanism is that the MAP-2 rich cells throughout the cerebral cortex correspond almost exactly with the cortical cells containing muscarinic receptors. Many of these cholinoceptive, MAP-2 rich cells are large pyramidal cell types, but some are also small pyramidal cells and nonpyramidal types. The third reason for proposing the current mechanism is that cholinergic afferents are module-specific; cholinergic axons terminate wholly within individual cortical modules. The cholinergic afferents may be unique in this regard. Finally, the tapering apical dendrites of pyramidal cells are proposed as primary sites for cholinergic mediation of linkages between MAP-2 and microtubules because especially high amounts of MAP-2 are found here. Also, the possibility is raised that muscarinic actions on MAP-2 could modulate microtubular coherence and self-collapse, phenomena that have been suggested to underlie consciousness.

Cholinergic Fibers↗
PubMed1999

Dendritic encoding: an alternative to temporal synaptic coding of conscious experience.

In this commentary, arguments are made for a dendritic code being preferable to a temporal synaptic code as a model of conscious experience. A temporal firing pattern is a product of an ongoing neural computation; hence, it is based on a neural algorithm and an algorithm may not provide the most suitable model for conscious experience. Reiteration of a temporal firing code as suggested in a preceding article (Helekar, 1999) does not necessarily improve the situation. The alternative model presented here is that certain synaptic activity patterns, possibly those possessing universal features as suggested by Helekar, can become encoded in the dendritic structure. Following dendritic encoding, quantum phenomena in those specific dendrite sets could illuminate the static image of that encoded synaptic activity. It is the activation of the static image that would be equivalent to conscious experience; thus, conscious awareness would not be directly affiliated with synaptic activity. This dendrite encoding model may go farther than other models to explain the gestalt nature of consciousness, insofar as quantum entanglement could produce an interconnectedness between specific sets of dendrites-an interconnectedness that need not be based on neural computation or neural connections.

Consciousness↗
PubMed2001

A field theory of consciousness.

This article summarizes a variety of current as well as previous research in support of a new theory of consciousness. Evidence has been steadily accumulating that information about a stimulus complex is distributed to many neuronal populations dispersed throughout the brain and is represented by the departure from randomness of the temporal pattern of neural discharges within these large ensembles. Zero phase lag synchronization occurs between discharges of neurons in different brain regions and is enhanced by presentation of stimuli. This evidence further suggests that spatiotemporal patterns of coherence, which have been identified by spatial principal component analysis, may encode a multidimensional representation of a present or past event. How such distributed information is integrated into a holistic precept constitutes the binding problem. How a precept defined by a spatial distribution of nonrandomness can be subjectively experienced constitutes the problem of consciousness. Explanations based on a discrete connectionistic network cannot be reconciled with the relevant facts. Evidence is presented herein of invariant features of brain electrical activity found to change reversibly with loss and return of consciousness in a study of 176 patients anesthetized during surgical procedures. A review of relevant research areas, as well as the anesthesia data, leads to a postulation that consciousness is a property of quantum-like processes, within a brain field resonating within a core of structures, which may be the neural substrate of consciousness. This core includes regions of the prefrontal cortex, the frontal cortex, the pre- and paracentral cortex, thalamus, limbic system, and basal ganglia.

Brain↗
PubMed2004

Relations between emotion and conscious recollection of true and false autobiographical memories: an investigation using lorazepam as a pharmacological tool.

RATIONALE: Conscious recollection for autobiographical memory is the subjective experience of reliving a personal event mentally. Its frequency is strongly influenced by the emotion experienced at the time of the event. OBJECTIVE: We addressed the issue of whether conscious recollection for autobiographical memories is also influenced by the emotion experienced at the time of retrieval. We used lorazepam, a benzodiazepine, as a pharmacological tool to modulate this emotional experience. METHODS: Autobiographical memories were recorded in eight healthy volunteers using a diary study methodology. Each day, four entries were made by each subject: two true events, one altered event and one false event. For each event, the subjects were asked to rate emotional variables at encoding and at retrieval. Two months later, there were two sessions of recognition tests during which the subjects received orally an acute administration of either lorazepam (0.038 mg/kg) or placebo using a cross-over design. Subjective states of awareness were assessed using the Remember/Know/Guess procedure. RESULTS: Compared to placebo, lorazepam increased levels of conscious recollection, as assessed by Remember responses, for both true and false memories and induced an overestimation of the personal significance and emotional intensity of past events. Structural equation modelling showed that this overestimation was causal in the increased frequency of conscious recollection. CONCLUSIONS: Our results provide experimental evidence that the frequency of conscious recollection for both true and false autobiographical memories is influenced by the emotion experienced at the time of retrieval.

Adult↗
PubMed1997

Comparison of the effects of stimulating extensor group I afferents on cycle period during walking in conscious and decerebrate cats.

Previous studies have reported that stimulation of group I afferents from extensor muscles prolongs stance duration during walking in decerebrate cats. The main objective of this investigation was to determine whether this phenomenon occurs during walking in conscious cats. In conscious cats without lesions of the central nervous system (CNS), stimulation of group I afferents in the lateral gastrocnemius/soleus (LGS) nerve during stance prolonged extensor burst duration and increased the cycle period in five of seven animals. The mean increases in cycle period were modest, ranging from 6 to 22%. In five of six animals that walked both quadrupedally and bipedally at the same rate, the effects on cycle period were stronger during bipedal stepping (18% mean increase in cycle period compared with 9%). The stimulated nerves were transected and the experimental procedure was usually delayed in the conscious animals for 2-3 days following implantation of the stimulating electrodes. To assess whether chronic axotomy of the LGS nerve was a factor in the decreased effectiveness, four of the cats with chronic nerve section were decerebrated and their LGS nerves were stimulated after the animals began to spontaneously walk on a motorized treadmill. In all four of these animals, the effects of stimulating the chronically cut LGS nerve on the step cycle period became stronger following decerebration. However, these effects were not as strong as those produced when an acutely sectioned LGS nerve was stimulated. During both quadrupedal and bipedal walking, stimulation of the LGS nerve increased the amplitude of the medial gastrocnemius (MG) electromyogram. The augmented activity of the MG muscle contributed to an increased extension of the ankle during stimulated steps. The conclusion from these experiments is that stimulation of the group I afferents in extensor nerves can prolong stance in the conscious cat, but this effect is weaker than in decerebrate animals. It is likely that transmission in the polysynaptic group I pathways controlling stance duration is regulated in a complex fashion by descending signals from the brain in the conscious animal.

Afferent Pathways↗