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PubMed1989

Geophysical variables and behavior: LV. Predicting the details of visitor experiences and the personality of experients: the temporal lobe factor.

The visitor experience, a more intense form of the normal sense of presence, emphasizes the deep belief of personal contact with an extraterrestrial (or religious) entity. Phenomenological details of visitor experiences are expected to reflect the functions of deep temporal lobe structures; common details involve cosmic meaningfulness, vestibular experiences, flickering, complex visual sensations and alimentary references. After intense experiences, interictal-like behaviors similar to religious conversions (widening affect, sense of personal, desire to spread the word, concern about Man's destiny) emerge. Normal people who are prone to these experiences show frequent temporal lobe signs and specific personality characteristics that include enhanced creativity, suggestibility, mild hypomania, anxiety, and emotional lability. Learning histories that encourage the use of right temporal lobe functions for the consolidation of memory, such as compartmentalization of beliefs or repression due to early sexual abuse, predispose to intense visitor experiences. The most frequent precipitants are psychological depression, personal (existential) stress and proximal exposure to the focal tectonic strain fields that accompany luminous phenomena. Possible neuropsychological mechanisms are discussed.

Amygdala↗

PubMed1985

Duchenne muscular dystrophy: a case with prolonged survival.

We report the case of a patient with confirmed Duchenne muscular dystrophy who lived a useful and improved life until age 34. He was first seen in our Muscular Dystrophy Clinic when he was 14; at that time he was functionally quadriplegic and required assistance for all activities of daily living. At age 17, ventilatory insufficiency developed and the patient was provided with a positive pressure device (mouthpiece) to augment his ventilation. A year later he learned the technique of glossopharyngeal breathing. After surviving acute pneumonia at age 24, he became a licensed real estate salesman and was married at age 29 to his attendant (the marriage ended in divorce). He eventually enrolled as a student at Ohio State University, lived on campus, and moved about in a powered wheelchair. He died an accidental death by drowning at age 34 when his wheelchair veered suddenly into a pond eight feet deep.

Adult↗

PubMed1992

Behavioural and electrophysiological studies of entorhinal cortex lesions in the rat.

Bilateral ibotenic acid injections aimed at the entorhinal cortex (EC) lesioned the EC and subiculum in 30% of animals (group EC/S) and caused additional hippocampal damage in 50% (group RH). Both lesions increased acetylcholinesterase (AChE) staining in the intermediate molecular layer of the dentate gyrus. EC/S lesions increased diurnal deep sleep and the incidence of spindles but decreased REM sleep. RH lesions increased nocturnal deep sleep and decreased nocturnal quiet sleep. Both lesions reduced power over the theta frequency range from 6-10 Hz for epochs of REM sleep and quiet waking but not deep sleep. Peak frequency was unaffected. The RH group and a subset of the EC/S group were nocturnally, but not diurnally, hyperactive. Six weeks after the lesion there was no evidence for hyperactivity in a novel open field. The EC/S lesion impaired exploration as indicated by reduced motility and rearing in an open field and by the failure of EC/S-lesioned rats to increase contact time in response to a novel olfactory cue. Place navigation learning in a Morris maze was not affected by EC/S or RH lesions. However, when the spatial location of the hidden platform was shifted EC/S-lesioned rats were impaired. The sprouting response, reduced theta power and exploration deficits resemble those reported following electrolytic lesions, but the lack of effect on place navigation learning contrasts with reports of impaired spatial learning following electrolytic lesions. The data prompt a reexamination of the role which the EC projection to the hippocampus plays in spatial learning.

Animals↗

PubMed2005

Global workspace theory of consciousness: toward a cognitive neuroscience of human experience.

Global workspace (GW) theory emerged from the cognitive architecture tradition in cognitive science. Newell and co-workers were the first to show the utility of a GW or "blackboard" architecture in a distributed set of knowledge sources, which could cooperatively solve problems that no single constituent could solve alone. The empirical connection with conscious cognition was made by Baars (1988, 2002). GW theory generates explicit predictions for conscious aspects of perception, emotion, motivation, learning, working memory, voluntary control, and self systems in the brain. It has similarities to biological theories such as Neural Darwinism and dynamical theories of brain functioning. Functional brain imaging now shows that conscious cognition is distinctively associated with wide spread of cortical activity, notably toward frontoparietal and medial temporal regions. Unconscious comparison conditions tend to activate only local regions, such as visual projection areas. Frontoparietal hypometabolism is also implicated in unconscious states, including deep sleep, coma, vegetative states, epileptic loss of consciousness, and general anesthesia. These findings are consistent with the GW hypothesis, which is now favored by a number of scientists and philosophers.

Cognition↗

PubMed1991

Absence epilepsy and the level of vigilance in rats of the WAG/Rij strain.

In man, a relationship exists between sleep-wake states and absence epilepsy. During wakefulness, spike-wave discharges predominantly occur when the level of vigilance is not high, while during sleep they have a preference to occur during slow-wave sleep. During this latter type of sleep, spike-wave discharges prevail in periods where slow-wave sleep is light. In a series of experiments, the WAG/Rij rat model for absence epilepsy was characterized with respect to the relationships between the level of vigilance, sleep-wake states and the occurrence of spike-wave discharges. In the first experiment, continuous recordings were made for a period of 48 h and a clear circadian rhythm was established for the number of spike-wave discharges. A maximum appeared during the middle of the dark period of the rat, whereas a minimum was detected directly after the onset of the light period, the time period during which deep slow-wave sleep predominates. The relationship of spike-wave discharges with states of vigilance was elaborated in a second study. Spike-wave discharges were mainly found during light slow-wave sleep, during passive wakefulness and in transition phases from sleep to wakefulness. During REM sleep no spike-wave discharges were found. In the last three experiments, the level of alertness was enhanced by various procedures as photostimulation, a learning task and deprivation of REM sleep. In all cases, an increase of alertness decreased the amount of epilepsy.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed2002

Automated annotation of keywords for proteins related to mycoplasmataceae using machine learning techniques.

MOTIVATION: With the increase in submission of sequences to public databases, the curators of these are not able to cope with the amount of information. The motivation of this work is to generate a system for automated annotation of data we are particularly interested in, namely proteins related to the Mycoplasmataceae family. Following previous works on automatic annotation using symbolic machine learning techniques, the present work proposes a method of automatic annotation of keywords (a part of the SWISS-PROT annotation procedure), and the validation, by an expert, of the annotation rules generated. The aim of this procedure is twofold: to complete the annotation of keywords of those proteins which is far from adequate, and to produce a prototype of the validation environment, which is aimed at an expert who does not have a deep knowledge of the structure of the current databases containing the necessary information s/he needs. RESULTS: As for the first objective, a rate of correct keywords annotation of 60% is reported in the literature. Our preliminary results show that with a slightly different method, applied this method to data related to Mycoplasmataceae only, we are able to increase that rate of correct annotation.

Abstracting and Indexing↗

PubMed2003

The quest for resilience.

In less turbulent times, executives had the luxury of assuming that business models were more or less immortal. Companies always had to work to get better, but they seldom had to get different--not at their core, not in their essence. Today, getting different is the imperative. It's the challenge facing Coca-Cola as it struggles to raise its "share of throat" in noncarbonated beverages. It's the task that bedevils McDonald's as it tries to restart its growth in a burger-weary world. It's the hurdle for Sun Microsystems as it searches for ways to protect its high-margin server business from the Linux onslaught. Continued success no longer hinges on momentum. Rather, it rides on resilience-on the ability to dynamically reinvent business models and strategies as circumstances change. Strategic resilience is not about responding to a onetime crisis or rebounding from a setback. It's about continually anticipating and adjusting to deep, secular trends that can permanently impair the earning power of a core business. It's about having the capacity to change even before the case for change becomes obvious. To thrive in turbulent times, companies must become as efficient at renewal as they are at producing today's products and services. To achieve strategic resilience, companies will have to overcome the cognitive challenge of eliminating denial, nostalgia, and arrogance; the strategic challenge of learning how to create a wealth of small tactical experiments; the political challenge of reallocating financial and human resources to where they can earn the best returns; and the ideological challenge of learning that strategic renewal is as important as optimization.

Commerce↗

PubMed2003

Using models to enhance the intellectual content of learning in developmental biology.

Models have been particularly useful in developmental biology over the last 30 years. At first, underlying control mechanisms were poorly understood, but over time a wealth of detailed information became available to provide an increasingly detailed knowledge of underlying mechanisms, at levels from genes through cells to organs, organisms and populations. Models are also of great value in teaching developmental biology, as they allow students to explore phenomena hard to perceive directly because of their scale, accessibility, expense or other considerations. A model may allow students to "experiment" in ways which would be impractical in real life, as well as give them a deep understanding of competing hypotheses of development. Lastly, students can be challenged to produce models of their own, whereas only rarely are they able to carry out original experiments. I discuss two main kinds of models and their uses in generating, testing and expounding hypotheses and point out dangers in the use of models in education. Models may draw upon and reflect the consensus paradigm in the field: a researcher may be able to appreciate that models are interim conditional statements of probability and use them to generate new knowledge. A student may be less able to do so and may fail to appreciate where new knowledge will come from. And unlike physics, biology is stochastic and contingent and can never be entirely deduced from first principles, implying that models can never be as perfect in any biological field as they can be in some other fields.

Developmental Biology↗

PubMed1998

The neuropathology of adult HIV infection.

Since the onset of the acquired immune deficiency syndrome (AIDS) epidemic fifteen years ago, much has been learned about the effects of the human immunodeficiency virus (HIV) in the nervous system. This review summarizes the pathology findings in the central nervous system (CNS). There is now abundant evidence that HIV can infect the CNS directly, leading to a characteristic HIV encephalitis (HIVE) which occurs in 10-50 p. 100 of AIDS autopsy series. Multinucleated giant cells are the pathognomonic feature of HIVE and are found predominantly in the central white matter and deep grey matter. Evidence of productive HIV infection in the CNS is confined to cells of the microglial/macrophage lineage, from which the giant cells are almost certainly derived. These cells are known to express both CD4 and beta-chemokine receptors, which act in conjunction to permit HIV entry. Restricted infection of astrocytes has also been identified by a variety of methods. HIVE is frequently associated with white matter damage ranging from inflammatory (microglia, macrophages and sparse lymphocytes) to degenerative (myelin loss and axonal damage) pathology. Although giant cells are seen less frequently in neocortical grey matter, significant neuronal loss has been established in a number of studies. Recent investigations using markers of apoptosis, (including TUNEL, Bcl-2 and BAX), have established the presence of DNA damage in some neurons and in other cell types. Axonal damage has also been confirmed by evidence of amyloid precursor protein expression. The CNS is also vulnerable to opportunistic infections and high grade B-cell lymphomas as a result of the immune suppression of advanced HIV infection. Cytomegalovirus (CMV) infection is reported in 10-30 p. 100 of AIDS cases at autopsy, toxoplasma in 10-25 p. 100, progressive multifocal leucoencephalopathy in about 5 p. 100 and lymphomas, usually primary, in up to 10 p. 100. A wide variety of other infections has also been reported. These may coexist with HIVE and may be difficult to diagnose in life. CMV gives rise to microglial nodular encephalitis, ventriculitis, necrotising encephalitis and myelo-radiculitis. Presymptomatic HIV positive patients do not show HIVE or opportunistic infections or lymphomas in the CNS. They frequently display a low-grade T-cell infiltrate in the leptomeninges and parenchyma, particularly around vessels. This lymphocytic infiltrate has been attributed to presumed early invasion of the CNS by HIV although the exact timing of entry is uncertain. It is possible that reported abnormalities in presymptomatic cases such as gliosis, microglial activation and rising proviral load may anticipate the onset of HIVE but most studies show that significant CNS damage and HIV-related pathology is confined to patients with AIDS. HIV-related pathology in the spinal cord includes not only HIV myelitis, opportunistic infections and lymphomas, but also vacuolar myelopathy (VM) which affects predominantly the dorsolateral white matter tracts. The cause of VM is not understood and has not been unequivocally linked with HIV infection. It is noted that none of these neuropathological features (including HIVE) correlates exactly with the clinical expression of AIDS-related dementia (ARD). The exact contribution of macrophage activation and cytokine release, astrocytic infection, neuronal loss and axonal damage to the neuropsychiatric syndromes of advanced HIV infection remain to be determined. While the current understanding of the pathogenesis of HIVE and ARD is beyond the scope of this review it is axiomatic that accurate documentation of neuropathology findings will help to resolve the outstanding dilemmas relating to HIV infection of the CNS. There is considerable optimism that progress in therapeutic regimes for HIV-infected patients will succeed in eliminating the virus from the blood and from lymphoid tissue. (ABSTRACT TRUNCATED)

AIDS-Related Opportunistic Infections↗

PubMedDate not supplied

[Effect of the local administration of 5,7-DHT and 6-OHDA into the neocortex on the learning and exploratory behavior of rats in an open field].

On Wistar rats characteristics were studied of investigating behaviour in the open field, of learning of conditioned food-reinforced reaction and also of BA and their metabolites content in various brain structures under local intracerebral injections of specific neurotoxins; 6-hydroxydopamine (6-OHDA) and 5,7-dihydroxytryptamine (5,7-DHT), abolishing correspondingly catecholaminergic and serotoninergic terminals. Bilateral injection of 6-OHDA in the neocortex led to a weakening of rats investigating activity in the open field and to an increase of the time of fulfillment of the forming of conditioned food-reinforced reaction. Administration of 5,7-DHT was accompanied by an increase of the investigating behaviour in the open field and a reduction of the duration of the forming of conditioned reaction. Administration of 6-OHDA to the neocortex caused a lowering of catecholamines level in the frontal area of the neocortex and the hippocampus. Analogous administration of 5,7-DHT elicited simultaneously with a deep level lowering of 5-HT and its metabolite in these structures, a change of catecholamines content which testifies to a lesser specificity of the neurotoxin 5,7-DHT in comparison with 6-OHDA. Structures lesion of serotoninergic and catecholaminergic systems of the frontal cortex and the hippocampus brought about by a local administration of 6-OHDA and 5,7-DHT in the neocortex was accompanied by differently directed changes in animals behaviour.

5,7-Dihydroxytryptamine↗

PubMed2005

Errors and pitfalls in the non-invasive management of atrial fibrillation.

Atrial fibrillation (AF) is the most common arrhythmia encountered in clinical practice while it has a significant impact on morbidity and mortality. The errors and pitfalls in the management of AF patients are not uncommon. These include errors in detection and management of the underlying conditions that promote and perpetuate the arrhythmia, in the selection and monitoring of antithrombotic treatment, in the selection of appropriate strategy for arrhythmia management (rate or rhythm control), in the cardioversion procedure, in the prevention of recurrence after cardioversion, in the acute or chronic control of heart rate, and in the monitoring of drug toxicities. The heterogeneity of the disease along with the diversity of current treatment options mainly account for these problems. Nevertheless, deep knowledge of the evidence-based therapeutic approaches, as well as the development of individualized therapeutic strategies, can substantially improve the effective management of such patients.

Atrial Fibrillation↗

PubMed2003

Both concreteness and age-of-acquisition affect reading accuracy but only concreteness affects comprehension in a deep dyslexic patient.

As concreteness correlates very highly with the age-of-acquisition (AoA) of words, we attempted to disentangle the effects of these two variables in the oral reading and comprehension performance of the deep dyslexic patient LW. The results of a multiple regression analysis of LW's reading of 217 words showed that both AoA and concreteness affect reading accuracy, with the AoA effect being most apparent for her reading of concrete words. However, concreteness and not AoA affected LW's performance in matching spoken definitions to printed words, both when the distractors were semantically unrelated and when they were related. These data are interpreted in terms of a model of reading in deep dyslexia in which concreteness affects the ease with which semantics are accessed and can activate lexical representations, and AoA affects the ease with which lexical phonology becomes available for spoken word production.

Age Factors↗

PubMed1996

The health care experience of patients with low literacy.

OBJECTIVES: To understand the difficulties that patients with poor reading ability have interacting with the health care system and to identify the coping mechanisms they use to deal with these problems. DESIGN: Focus groups and individual interviews with patients who are illiterate and patients with low literacy. SETTING: Two large, urban public hospitals. PARTICIPANTS: Sixty patients with marginal to poor reading abilities as measured by the Rapid Estimate of Adult Literacy in Medicine were interviewed in focus groups or individual interviews. MEASUREMENTS AND MAIN RESULTS: Patients with low literacy harbor a deep sense of shame, which is reinforced by hospital staff who become frustrated or angry when someone cannot complete a form or read instructions. Seeking medical care is intimidating for patients with low literacy because they cannot understand signs and registration forms. Many patients recounted serious medication errors resulting from their inability to read labels. To cope with these problems, the patients with low literacy rely heavily on oral explanations, visual clues, and demonstrations of tasks to learn new material. Most also use a friend or family member as a surrogate reader. CONCLUSIONS: Patients with poor reading ability have important problems accessing the health care system, understanding recommended treatments, and following the instructions of providers. Because of their shame, patients with low literacy may be unwilling to disclose their problem to health care providers, and screening tests of reading ability may be necessary to identify those who need special assistance. Patients' coping mechanisms give insight into possible interventions that may improve their interactions with the health care system.

Adult↗

PubMed2002

Spinal cord injury medicine. 2. Medical complications after spinal cord injury: Identification and management.

UNLABELLED: This is a self-directed learning module that reviews medical complications associated with spinal cord injury (SCI). It is part of a chapter on SCI medicine in the Self-Directed Physiatric Educational Program for practitioners and trainees in physical medicine and rehabilitation. This article includes discussion of common medical complications that impact rehabilitation and long-term follow-up for individuals with SCI. Issues addressed include the rehabilitation approach to SCI individuals with pressure ulcers, unilateral lower-extremity swelling (deep venous thrombosis, heterotopic ossification, fractures), along with the pathophysiology, assessment, and treatment of spasticity, autonomic dysreflexia, orthostatic hypotension, and pain. OVERALL ARTICLE OBJECTIVE: To describe diagnostic and treatment approaches for medical complications common to individuals with SCI.

Adult↗

PubMed1990

Tibial defects. Reconstruction using the method of Ilizarov as an alternative.

Although used in the USSR since the 1950s, the method of Ilizarov has only recently been employed in North America to manage bone defects. Seven cases of patients with tibial bone defects are presented (five with deep infection) that were treated by gradual compression at the defect with one or two transported tibial segments that not only filled the tibial defect but preserved or regained the original bone length. Six of the seven patients had their defect obliterated while leg length was maintained. The method is minimally invasive, allows immediate weight-bearing and permits modifications in strategy while treating the bone defects but requires close attention to detail and has a steep learning curve.

External Fixators↗

PubMed2001

A hybrid input-output approach to model metabolic systems: an application to intracellular thiamine kinetics.

Models of the dynamics of complex metabolic systems offer potential benefits to the deep comprehension of the system under study as well as for the performance of certain tasks. Unfortunately, dynamic modeling of a great deal of metabolic systems may be problematic due to the incompleteness of the available knowledge about the underlying mechanisms and to the lack of an adequate observational data set. In theory, a valid alternative to classical structural modeling through ordinary differential equations could be represented by input-output approaches. But, in practice, such methods, which learn the nonlinear dynamics of the system from input-output data, fail when the experimental data set is poor either in size or in quality. Such a situation is not rare in the case of metabolic systems. This paper deals with a hybrid approach which aims at overcoming the problems addressed above. More specifically, it allows us to solve the identification problems of the intracellular thiamine kinetics in the intestine tissue. The method, which is half way between the structural and input-output approach, uses the outcomes of the simulation of a qualitative structural model to build a good initialization of a fuzzy system identifier. Such an initialization allows us to efficiently cope with both the incompleteness of knowledge and the inadequacy of the available data set, and to derive an input-output model of the intracellular thiamine kinetics in the intestine tissue. The comparison of the predictions of the intracellular thiamine kinetics obtained by the application of such a model with those obtained by traditional approaches, namely compartmental models, neural networks, and fuzzy systems, highlighted a better performance of our model. As the structural assumptions are relaxed, we obtained a model slightly less informative than a purely structural one but robust enough to be used as a simulator. The paper also discusses the interpretative potential offered by such a model, as tested on diabetic subjects.

Animals↗

PubMed2003

Direct and indirect perforator flaps: the history and the controversy.

LEARNING OBJECTIVES: After studying this article, the participant should be able to: 1. Recognize the major role of the vascular supply to a cutaneous flap. 2. Predict its reliability. 3. Understand basic schemes for classification. 4. Realize that the evolution of these concepts is an ongoing dynamic process. Currently, the vascular supply to the fascial plexus is considered the factor of greatest importance in ensuring the reliability of any skin-bearing flap. The multiplicity of origins of the deep fascial perforators to this plexus has led to a bewildering array of terminology intended to encompass all possible flap options. A brief review of the history of the evolution of cutaneous flaps provides insight essential in understanding a simple proposal for their classification. Because all fascial perforators course either directly from a source vessel or indirectly first through some other tissue to ultimately reach the suprafascial layer, the corresponding flaps based on any such perforators could most simply be termed either direct perforator flaps or indirect perforator flaps, respectively.

Fascia↗

PubMed2005

Does bilateral stimulation of the subthalamic nucleus aggravate apathy in Parkinson's disease?

OBJECTIVE: High frequency stimulation of the subthalamic nucleus (STN) dramatically decreases motor disability in patients with Parkinson"s disease (PD), but has been reported to aggravate apathy. The aim of this study was to analyse the effect of STN stimulation on motivation and reward sensitivity in a consecutive series of PD patients. METHODS: Apathy and reward sensitivity (Apathy Scale, Stimulus-Reward Learning, Reversal, Extinction, and Gambling tasks) were assessed in 18 PD patients treated by bilateral STN stimulation ("on" and "off" conditions) compared with 23 matched patients undergoing long term treatment with levodopa ("on" and "off" conditions). RESULTS: Apathy decreased under both STN stimulation and levodopa treatment, whereas explicit and implicit stimulus reward learning was unchanged. CONCLUSIONS: Bilateral STN stimulation in PD patients does not necessarily have a negative effect on motivation and reward sensitivity and can even improve apathy provided patients have been appropriately selected for neurosurgery.

Antiparkinson Agents↗