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At least 649 records · Page 36Linked to original sources
PubMed1997

Conscious pain mapping.

STUDY OBJECTIVE: To present the technique and usefulness of conscious pain mapping. DESIGN: Prospective, observational study (Canadian Task Force classification II-2). SETTING: Gynecology departments of a university-affiliated hospital and a private community hospital. PATIENTS: Fifty consecutive women undergoing diagnostic microlaparoscopy. INTERVENTIONS: Conscious pain mapping was performed in all 50 women. MEASUREMENTS AND MAIN RESULTS: Conscious pain mapping helped to identify foci of chronic pelvic pain. The appendix and pelvic adhesions accounted for a significant amount of pelvic pain in these women. CONCLUSIONS: Conscious pain mapping helps to uncover sites of pelvic pain that might not be identified during traditional laparoscopy under general anesthesia.

Adolescent↗
PubMed2003

The mind's best trick: how we experience conscious will.

We often consciously will our own actions. This experience is so profound that it tempts us to believe that our actions are caused by consciousness. It could also be a trick, however - the mind's way of estimating its own apparent authorship by drawing causal inferences about relationships between thoughts and actions. Cognitive, social, and neuropsychological studies of apparent mental causation suggest that experiences of conscious will frequently depart from actual causal processes and so might not reflect direct perceptions of conscious thought causing action.

Journal Article↗
PubMed1996

Lymphatic transport of halofantrine in the conscious rat when administered as either the free base or the hydrochloride salt: effect of lipid class and lipid vehicle dispersion.

The intestinal lymphatic transport of halofantrine, an important, highly lipophilic antimalarial drug, has been studied in a conscious rat model after oral administration. In these studies, the lymphatic transport of Hf free base when coadministered with lipid was approximately 20% of the administered dose compared with 5% transport after administration of the HCl salt with or without lipid. These differences in transport can be attributed to the increased lipophilicity of the free base (relative to the HCl salt) thereby facilitating greater association of Hf base with the products of luminal lipid digestion and the subsequent interaction with the intestinally derived chylomicrons responsible for lymphatic drug transport. In contrast to previous results in an anesthetized rat model where lymphatic transport was dependent on the characteristics of the intraduodenally administered lipid formulations, the lymphatic transport of Hf base in the conscious rat was independent of both the class of administered lipid (triglyceride or fatty acid) and the extent of formulation dispersion (micellar lipid or lipid solution). Considering the different lymphatic transport profiles of Hf base in the anesthetized and conscious rat models, it is proposed that the lipid vehicle effects observed in the intraduodenally dosed anesthetized model most likely reflects the lack of gastric processing by preduodenal lipase and the shear action of the stomach otherwise present in the conscious rat model.

Administration, Oral↗
PubMed2005

The role of critical consciousness in multicultural practice: examining how its strength becomes its limitation.

Given the strengths of developing critical consciousness in multicultural practice, why do roadblocks persist? This article examines how the strengths of developing critical consciousness in multicultural practice can paradoxically become its limitation. Literatures from counseling psychology, clinical psychology, social psychology, social work, feminist theory, and critical theory are integrated in a discussion of the various components and strengths involved in working toward critical consciousness. This literature is then used to discuss some of the cognitive and affective limitations to achieving critical consciousness. Implications for practice are discussed.

Awareness↗
PubMed1993

What's in a name? The moderating role of public self-consciousness on the relation between brand label and brand preference.

Products with bargain-brand labels are generally considered to be cheap or inferior in comparison with products with national brand labels. Publicly self-conscious individuals might accept products with national brand labels and reject products with bargain brand labels to enhance their public images. A field experiment was conducted to test this hypothesis. Three hundred twenty adults, frequenting public locations, tasted and rated either national brand or bargain brand peanut butters that had either national brand or bargain brand labels. They also completed the Public Self-Consciousness scale (A. Fenigstein, M. F. Scheier, & A. H. Buss, 1975). Ratings of products with national brand labels were expected to be positively correlated with level of public self-consciousness, whereas ratings of products with bargain brand labels were expected to be negatively correlated with level of public self-consciousness. The author's results confirmed both predictions.

Adult↗
PubMed2004

African American students' ratings of Caucasian and African American counselors varying in racial consciousness.

African American college students (63 female, 30 male) rated vignettes of counselors varying in racial consciousness (high vs. low) and race (African American vs. Caucasian). Participants then completed a counselor rating scale and the Racial Identity Attitude Scale (Short Form; T. A. Parham & J. E. Helms, 1981). African American counselors were rated more favorably than White counselors, and high racially conscious counselors were rated more favorably than low racially conscious counselors. The African American counselor with high racial consciousness was rated the most favorably. Several significant correlations were found between participants' racial identity attitudes and their ratings of counselors. Implications for the training of both African American and White counselors are considered.

Adolescent↗
PubMed2002

Voluntary action and conscious awareness.

Humans have the conscious experience of 'free will': we feel we can generate our actions, and thus affect our environment. Here we used the perceived time of intentional actions and of their sensory consequences as a means to study consciousness of action. These perceived times were attracted together in conscious awareness, so that subjects perceived voluntary movements as occurring later and their sensory consequences as occurring earlier than they actually did. Comparable involuntary movements caused by magnetic brain stimulation reversed this attraction effect. We conclude that the CNS applies a specific neural mechanism to produce intentional binding of actions and their effects in conscious awareness.

Adult↗
PubMed2001

The effect of intravenous dexmedetomidine premedication on the dose requirement of propofol to induce loss of consciousness in patients receiving alfentanil.

Dexmedetomidine reduces the dose requirements for opioids and anaesthetic agents. We conducted a single-centre, open-label, noncomparative phase II study of the effect of intravenous dexmedetomidine on the dose requirement of propofol to induce loss of consciousness in 49 ASA I and II patients. The initial dexmedetomidine infusion scheme was reduced twice because of adverse events. Forty patients who received the final infusion scheme were randomly allocated to receive one of five stepped propofol infusions; loss of consciousness was assessed after 21 min. The ED50 for the final infusion rate of propofol to suppress consciousness was 3.45 mg x kg(-1) x h(-1) (95% CL 2.7-4.2): ED95 was 6.68 mg x kg(-1) x h(-1) (95% CL 5.1-19.1), EC50 was 1.69 microg x ml(-1) (95% CL 0.95-2.5) and EC95 was 5.7 microg x ml(-1) (95% CL 3.2 to > 10). Our final dose of dexmedetomidine of 0.63 microg x kg(-1) caused a reduction in the overall concentration and dose of propofol required to produce loss of consciousness, but no significant shift in the dose-response curve compared with other studies.

Adolescent↗
PubMed1999

The combined use of propofol and fentanyl for outpatient intravenous conscious sedation.

BACKGROUND: Intravenous conscious sedation is currently being widely utilized for outpatient surgery including dermatologic surgery. Even though this type of anesthesia is typically administered by a trained, licensed anesthetist, it is important for dermatologists who either intend to or are currently utilizing this type of anesthesia to be familiar with some of the methods and agents that are commonly employed. OBJECTIVE: Propofol and fentanyl are two anesthetic agents that are in prevalent use for skin and soft tissue surgery of brief or limited duration. With the goal of familiarizing dermatologic surgeons with this form of anesthesia, a study was conducted to evaluate the safety and effectiveness of the combination of propofol and fentanyl when used for conscious sedation in an outpatient dermatology center. METHODS: Twenty patients, ages 25-65 years, who required conscious sedation were enrolled. Each patient received a standard dosage of fentanyl and propofol, as determined on a kilogram basis. Sedation time, total procedure time, recovery time, and total propofol dose, along with side effects, were determined. RESULTS: The mean onset to sedation was 52.5 seconds, the mean procedure time was 40 minutes 37 seconds, and the mean interval to recovery was 3 minutes 43 seconds, with a mean total dose of propofol of 5.83 mg/kg. Minimal side effects occurred. CONCLUSION: Propofol when used in conjunction with fentanyl appears to be a safe, quick, and effective method of providing conscious sedation.

Adult↗
PubMed1982

Pancreatic response to bolus injection of cholecystokinin-pancreozymin in anaesthetized and conscious rats fed raw soyaflour.

Pancreatic secretion was studied in rats fed raw soyafour before (basal) and after stimulation with cholecystokinin-pancreozymin (CCK) given in either ascending or descending dose orders ranging from 1.25 to 20 or from 20 to 1.25 Crick-Harper-Raper units (CHRU). These results were compared with those reported previously for animals fed a stock cube diet. Two experimental conditions were used: anaesthetized animals were tested immediately after cannulation of the pancreatic duct and conscious animals were tested 48 h after surgery. Basal flow was significantly increased in anaesthetized and conscious rats fed RSF compared with the respective animals fed cubes. Mean basal protein output was also increased, but this difference was not significant. The pancreatic response to the ascending and descending doses of CCK in anaesthetized rats fed RSF was linearly related to the log of the dose of CCK in both animals fed RSF and cubes, though the response to CCK was greater in the rats fed RSF. When ascending doses of CCK were given to conscious rats fed RSF, the protein output increased up to 10 CHRU of CCK but was inhibited by 20 CHRU of CCK, whereas it decreased after the first dose of CCK (1.25 CHRU) in animals fed cubes. When descending doses of CCK were given to animals fed RSF, protein output was greatest after the first dose and no simple relationship between dose and response was seen. Compared with rats fed cubes, the pancreas in rats fed RSF thus appears to respond to a given dose of CCK with increased secretion, and conscious animals fed RSF can tolerate a higher dose of CCK before protein output is inhibited. This is consistent with an increased population of acinar cells in the animals fed RSF, with each hypertrophied cell responding to CCK with increased secretion.

Animals↗
PubMed2006

Perceptual moments of conscious visual experience inferred from oscillatory brain activity.

Transient periods of synchronized oscillating neuronal discharges in the brain have been proposed to support the discrete perceptual moments underlying conscious visual experience. However, the information content of these perceptual moments remains a critical challenge to the understanding of consciousness. We uncovered this information content in four observers who consciously perceived each interpretation of the ambiguous Dali painting Slave Market with the Disappearing Bust of Voltaire. For each individual observer, we isolated the stimulus spatial frequency (SF) features underlying their overt judgments of the input as "the nuns" and "Voltaire". Every 2 ms between stimulus onset and overt response, we derived the sensitivity of the observer's oscillatory brain activity (in the theta, alpha, and beta bandwidths) to these SF features. Then, in each bandwidth, we estimated the moments (between stimulus onset and perceptual judgment) when perception-specific SF features were maximally integrated, corresponding to perceptual moments. We show that the centroparietal beta oscillations support perceptual moments underlying the conscious perception of the nuns, whereas theta oscillations support the perception of Voltaire. For both perceptions, we reveal the specific information content of these perceptual moments.

Behavior↗
PubMed2003

Brain potentials associated with conscious aftereffects induced by unseen stimuli in a blindsight subject.

The study is of brain activity in a blindsight subject (D.B.), who reports conscious visual afterimages of stimuli of which he is unaware when they are presented. This contrast offered a unique opportunity to study event-related potential recordings of conscious versus unconscious visual phenomena generated by the very same stimulus in the identical locus of the visual field. The behavioral results confirmed the reliability of the difference in the subject's report for inducing stimuli versus their aftereffects. The rationale of the event-related potential analysis was to subtract "on" signals from "off" signals, the latter associated with the onset of conscious events and the former for events that remained unconscious. Because there are inherent differences in on and off potentials, the subtractive resultants for the blind hemifield were compared with the same subtractions for the good hemifield when the subject was aware both of the stimuli and their afterimages. A differential pattern in subtractive resultants emerged with a strong anterior left frontal focus for the blind field and a posterior focus for the intact field. The results are compared with other studies suggesting an anterior focus for conscious visual events.

Afterimage↗
PubMed1998

Investigating neural correlates of conscious perception by frequency-tagged neuromagnetic responses.

In binocular rivalry, a subject views two incongruent stimuli through each eye but consciously perceives only one stimulus at a time, with a switch in perceptual dominance every few seconds. To investigate the neural correlates of perceptual dominance in humans, seven subjects were recorded with a 148-channel magnetoencephalography array while experiencing binocular rivalry. A red vertical grating flickering at one frequency was presented to one eye through a red filter and a blue horizontal grating flickering at a different frequency was presented to the other eye through a blue filter. Steady-state neuromagnetic responses at the two frequencies were used as tags for the two stimuli and analyzed with high-resolution power spectra. It was found that a large number of channels showed peaks at both frequencies, arranged in a horseshoe pattern from posterior to anterior regions, whether or not the subject was consciously perceiving the corresponding stimulus. However, the amount of power at the stimulus frequency was modulated in relation to perceptual dominance, being lower in many channels by 50-85% when the subject was not conscious of that stimulus. Such modulation by perceptual dominance, although not global, was distributed to a large subset of regions showing stimulus-related responses, including regions outside visual cortex. The results demonstrate a correlation between the conscious perception of a visual stimulus and the synchronous activity of large populations of neurons as reflected by steady-state neuromagnetic responses.

Adult↗
PubMed2006

Meal-induced insulin sensitization in conscious and anaesthetized rat models comparing liquid mixed meal with glucose and sucrose.

We have recently shown that meal-induced insulin sensitization (MIS) occurs after feeding and decreases progressively to insignificance after 24 h of fasting and is caused by action of a hepatic insulin sensitizing substance (HISS). In order to carry out quantitative studies of MIS, some standardized meal intake is required. Our objective was to establish animal models to be tested in both the conscious and anaesthetized state using intragastric injection of liquid meals in order to quantify MIS. Insulin sensitivity was assessed before and 90 min after the meal using the rapid insulin sensitivity test (RIST) which is a transient euglycaemic clamp. Rats tested in the conscious state were instrumented under anaesthesia 6-9 d prior to testing with catheters in the carotid artery, jugular vein and stomach. Meals, injected into the stomach, consisted of a liquid mixed meal, sucrose, glucose or water. The glucose sequestration in response to insulin increased by 90 % and 61 % following the liquid mixed meal (10 ml/kg) in conscious and anaesthetized rats, respectively. Glucose, sucrose and water did not effectively activate MIS. MIS was completely reversed in the conscious model by atropine and completely prevented from developing in the anaesthetized model that had previously undergone hepatic denervation. Gastric administration of a liquid mixed meal but not glucose or sucrose is capable of activating MIS for purposes of mechanistic studies and quantification of the MIS process. The feeding signal is mediated by the hepatic parasympathetic nerves.

Anesthesia↗
PubMed2003

Transient loss of consciousness as reason for admission to primary health care emergency room.

OBJECTIVE: To study the occurrence and main causes of transient loss of consciousness in primary health care. DESIGN: A 4-month prospective survey. SETTING: Primary health care emergency room of the City of Tampere, Finland. SUBJECTS: Consecutive patients, aged over 15 years, admitted to the emergency room. MAIN OUTCOME MEASURES: The overall prevalence of loss of consciousness divided into three subgroups: seizure, syncope and uncertain, and their distribution by gender and age. The prevalence of epilepsy, coronary heart disease and alcohol abuse among these diagnostic subgroups. RESULTS: Of all emergency room visits, 1.2% were for loss of consciousness. Of these, 53% were diagnosed as seizures, 33% as syncope attacks and 14% as uncertain. In the seizure group, 75% of patients were men and 67% had a history of alcohol abuse. In the syncope group, 44% of patients had coronary heart disease and 68% were women. CONCLUSION: Loss of consciousness is a fairly frequent problem for the primary health care emergency room. A history of alcohol abuse is commonly associated with seizures.

Adolescent↗
PubMedDate not supplied

Influence of dosage, consciousness, and nifedipine on the acute pressor response to intraperitoneally administered cadmium.

The acute pressor effect of intraperitoneally administered cadmium was explored over the dose range 0.015-2 mg/kg in both pentobarbital-anesthetized and conscious rats. The former first respondent at 0.031 mg/kg, and successive doublings of that dosage increased the highest pressures attained in a stepwise fashion until a dosage of 0.25 mg/kg, the maximally effective quantity, was reached. Arterial pressure did not rise in conscious rats until a dose of 1 mg/kg, which gave the maximum response within the range examined. Heart-rate changes with Cd were slight, and rarely significant at a given dosage, but pentobarbital invariably caused tachycardia. Anesthetized rats thus gave a graded response, while conscious animals reacted in an all-or-none fashion. The increased pressor responsiveness of rats under pentobarbital can not be ascribed to its cardiac parasympatholytic effects, since sensitivity was not conferred upon conscious rats when pretreated with atropine at a dose producing even greater tachycardia than that caused by pentobarbital. Nifedipine, which blocks calcium entry into smooth muscle cells, prevented the pressor response to cadmium when given as pretreatment and terminated an ongoing response when give intercurrently. Possible mechanisms to account for the observed behavior are considered.

Anesthesia↗
PubMed2003

Explicit neural representations, recursive neural networks and conscious visual perception.

The fundamental question as to whether the neural correlates of any given conscious visual experience are expressed locally within a given cortical area or more globally within some widely distributed network remains unresolved. We inquire as to whether recursive processing-by which we mean the combined flow and integrated outcome of afferent and recurrent activity across a series of cortical areas-is essential for the emergence of conscious visual experience. If so, we further inquire as to whether such recursive processing is essential only for loops between extrastriate cortical areas explicitly representing experiences such as color or motion back to V1 or whether it is processing between still higher levels and the areas computing such explicit representations that is exclusively or additionally essential for visual experience. If recursive processing is not essential for the emergence of conscious visual experience, then it should also be possible to determine whether it is only the intracortical sensory processing within areas computing explicit sensory representations that is required for perceptual experience or whether it is the subsequent processing of the output of such areas within more anterior cortical regions that engenders perception. The present analysis suggests that the questions posed here may ultimately become experimentally resolvable. Whatever the outcome, the results will likely open new approaches to identify the neural correlates of conscious visual perception.

Animals↗
PubMed2005

MEG phase follows conscious perception during binocular rivalry induced by visual stream segregation.

We have investigated an unusual form of binocular rivalry between two images that are flickered one to each eye, but are never presented simultaneously to the observer. The images were presented in alternation, with a brief dark period between the images. When the flicker frequency was < 5 Hz, the subjects primarily experienced a unitary flicker that alternated between the two images. When the flicker frequency was > 5 Hz, the subjects primarily experienced two single-image flickers that rival. We investigated magnetoencephalography (MEG) responses at the flicker frequency of the rival stimuli. We found that at some recording locations responses are phase-locked to the flicker that is consciously being perceived. At each flicker rate that induced rivalry, phase shifts following the conscious percept were found consistently at MEG sensors over midline frontal lobe. Most of these sensors show higher magnitude responses when two rivaling flickers are perceived than when a unitary alternating color flicker is perceived. At sensors over occipital lobe, the sensor locations that phase-locked to the perceived flicker depended on the color, orientation, and frequency of flicker. By contrast, sensors over parietal cortex respond preferentially to one flicker, even as the conscious percept changes. Apparently, a large-scale network of cell assemblies in occipital and frontal cortex, responds preferentially to the perceived stimulus during rivalry, and is sensitive to the timing of the flicker driving the conscious percept.

Adult↗