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PubMed1997

Neural mechanisms of mammalian olfactory learning.

In this review, we compare the neural basis of olfactory learning in three specialized contexts that occur during sensitive periods of enhanced neural plasticity. Although they involve very different behavioural contexts, they share several common features, including a dependence on noradrenergic transmission in the olfactory bulb. The most extensively characterized of these examples is the learning of pheromonal information by female mice during mating. While this form of learning is unusual in that the neural changes underlying the memory occur in the accessory olfactory bulb at the first stage of sensory processing, it involves similar neural mechanisms to other forms of learning and synaptic plasticity. The learning of newborn lamb odours after parturition in sheep, and the olfactory conditioning in neonatal animals such as rats and rabbits, are mediated by the main olfactory system. Although the neural mechanisms for learning in the main olfactory system are more distributed, they also involve changes occurring in the olfactory bulb. In each case, odour learning induces substantial structural and functional changes, including increases in inhibitory neurotransmission. In the main olfactory bulb, this probably represents a sharpening of the odour-induced pattern of activity, due to increases in lateral inhibition. In contrast, the different morphology of mitral cells in the accessory olfactory bulb results in increased self-inhibition, disrupting the transmission of pheromonal information. Although these examples occur in highly specialized contexts, comparisons among them can enhance our understanding of the general neural mechanisms of olfactory learning.

Animals↗
PubMed2002

Adaptation, punctuation and information: a rate-distortion approach to non-cognitive 'learning plateaus' in evolutionary process.

We extend recent information-theoretic phase transition approaches to evolutionary and cognitive process via the Rate Distortion and Joint Asymptotic Equipartition Theorems, in the circumstance of interaction with a highly structured environment. This suggests that learning plateaus in cognitive systems and punctuated equilibria in evolutionary process are formally analogous, even though evolution is not cognitive. Extending arguments by Adami et al. (2000), we argue that 'adaptation' is the process by which a distorted genetic image of a coherently structured environment is imposed upon a species.

Adaptation, Biological↗
PubMed2005

Discontinuous categories affect information-integration but not rule-based category learning.

Three experiments were conducted that provide a direct examination of within-category discontinuity manipulations on the implicit, procedural-based learning and the explicit, hypothesis-testing systems proposed in F. G. Ashby, L. A. Alfonso-Reese, A. U. Turken, and E. M. Waldron's (1998) competition between verbal and implicit systems model. Discontinuous categories adversely affected information-integration but not rule-based category learning. Increasing the magnitude of the discontinuity did not lead to a significant decline in performance. The distance to the bound provides a reasonable description of the generalization profile associated with the hypothesis-testing system, whereas the distance to the bound plus the distance to the trained response region provides a reasonable description of the generalization profile associated with the procedural-based learning system. These results suggest that within-category discontinuity differentially impacts information-integration but not rule-based category learning and provides information regarding the detailed processing characteristics of each category learning system.

Adult↗
PubMed2005

Decitabine dosing schedules.

5-Aza-2'-deoxycytidine (decitabine; Dacogen, MGI Pharma, Inc, Bloomington, MN) is a cytidine analog that inhibits DNA methyltransferases resulting in loss of DNA methylation with subsequent gene re-expression. This compound was first synthesized over 40 years ago and since that time much information has been learned regarding its mechanism of action. It took nearly 20 years before the dual mechanism of action was elucidated. At high doses decitabine is cytotoxic, while lower doses are associated with demethylating activity. This information sparked further clinical trials using a lower dosing schedule since the original studies using higher doses were associated with significant myelosuppression and induction toxicity. Current trials using lower dosing schedules, particularly in patients with hematologic malignancies, have shown significant promise for the future use of demethylating agents. Sequential and/or randomized phase I/II studies have suggested that decitabine is most active when administered at relatively low doses given via a short infusion. The drug is less active and more toxic when administered via continuous infusion, and increasing dose-intensity resulted in a higher response rate, suggesting a relationship between peak drug levels and response. Even with all the information we have learned, there is still a need to determine the optimal dosing schedule and the development of alternative dosing forms.

Azacitidine↗
PubMed2003

Information processing, dimensionality reduction and reinforcement learning in the basal ganglia.

Modeling of the basal ganglia has played a major role in our understanding of this elusive group of nuclei. Models of the basal ganglia have undergone evolutionary and revolutionary changes over the last 20 years, as new research in the fields of anatomy, physiology and biochemistry of these nuclei has yielded new information. Early models dealt with a single pathway through the nuclei and focused on the nature of the processing performed within it, convergence of information versus parallel processing of information. Later, the Albin-DeLong "box-and-arrow" model characterized the inter-nuclei interaction as multiple pathways while maintaining a simplistic scalar representation of the nuclei themselves. This model made a breakthrough by providing key insights into the behavior of these nuclei in hypo- and hyper-kinetic movement disorders. The next generation of models elaborated the intra-nuclei interactions and focused on the role of the basal ganglia in action selection and sequence generation which form the most current consensus regarding basal ganglia function in both normal and pathological conditions. However, new findings challenge these models and point to a different neural network approach to information processing in the basal ganglia. Here, we take an in-depth look at the reinforcement driven dimensionality reduction (RDDR) model which postulates that the basal ganglia compress cortical information according to a reinforcement signal using optimal extraction methods. The model provides new insights and experimental predictions on the computational capacity of the basal ganglia and their role in health and disease.

Animals↗
PubMed2001

Predictability, complexity, and learning.

We define predictive information I(pred)(T) as the mutual information between the past and the future of a time series. Three qualitatively different behaviors are found in the limit of large observation times T:I(pred)(T) can remain finite, grow logarithmically, or grow as a fractional power law. If the time series allows us to learn a model with a finite number of parameters, then I(pred)(T) grows logarithmically with a coefficient that counts the dimensionality of the model space. In contrast, power-law growth is associated, for example, with the learning of infinite parameter (or nonparametric) models such as continuous functions with smoothness constraints. There are connections between the predictive information and measures of complexity that have been defined both in learning theory and the analysis of physical systems through statistical mechanics and dynamical systems theory. Furthermore, in the same way that entropy provides the unique measure of available information consistent with some simple and plausible conditions, we argue that the divergent part of I(pred)(T) provides the unique measure for the complexity of dynamics underlying a time series. Finally, we discuss how these ideas may be useful in problems in physics, statistics, and biology.

Forecasting↗
PubMed1998

A framework to identify learning needs for continuing nurse education using information technology.

This paper concerns one of the main problems facing continuing nurse education, that of matching the learning needs of the individual nurse with the needs of the care setting. This endeavour is inescapable because of the necessity for giving high quality care within financial restraint. Modern information technology, it is suggested, can be helpful in fulfilling the task more easily. A theoretical framework is introduced as a possible solution for developing a computer program which, it is the hope of the author, will be available in the not so far future.

Computers↗
PubMed2006

Improving initial management of lower urinary tract symptoms in primary care: costs and patient outcomes.

OBJECTIVE: Guidelines for primary care management of lower urinary tract symptoms in older men recommend shared decision making regarding the choice of treatment. In this study we aimed to determine the costs and patient outcomes of an implementation strategy designed to enhance uptake of these guidelines. MATERIAL AND METHODS: The intervention comprised a distance learning programme for general practitioners, comprising evidence-based information, assessment of learning needs, a knowledge test and patient education materials. The control group only received the written guidelines. A cluster randomized trial in 187 older male patients compared costs and outcomes in the two study groups. A healthcare perspective was taken in the economic evaluation, with a 3-month time horizon. The primary health outcome was patient-reported urinary symptoms at 3 months. Costs relating to the distance learning package and the healthcare provided were considered, using undiscounted standardized prices. RESULTS: Patient-reported urinary symptoms at 3 months did not differ between the study groups: 66% and 61% with moderate symptoms and 7% and 11% with severe symptoms in the intervention and control groups, respectively. The mean total costs per patient were euro28.15 lower in the intervention group (euro93.11) compared to the control group (euro121.26), mainly because of a lower number of referrals to the urologist. A bootstrap analysis showed an incremental cost-effectiveness ratio of euro111.98 (95% CI -euro423 to +euro329). CONCLUSIONS: The distance learning programme did not change health outcomes, but it reduced costs in the first 3 months after an initial consultation compared to written guidelines. Studies with a longer follow-up period are needed.

Aged↗
PubMed1994

Informatics for nurse managers: integrating clinical expertise, business applications, and technology.

Nurse managers must become familiar with computers, information systems, and nursing informatics in order to be competitive in the future. Knowledge and skills for identifying critical data elements, organizing the data into information, and presenting it for decision making can be learned through formal and informal education. After learning to use computers and to apply nursing informatics, nurse managers will be equipped to make more relevant, data-driven management decisions. This article describes how nurse managers can identify business applications relevant to management, learn how to use them, and put nursing informatics to work in very practical ways.

Clinical Competence↗
PubMed2005

Acquiring long-term representations of visual classes following extensive extrastriate damage.

Different areas of human visual cortex are thought to play different roles in the learning of visual information: whereas in low/intermediate cortical areas, plasticity may be manifested by enhanced selectivity to learned visual features, in higher-level areas, plasticity may result in generalization and development of tolerance to degraded versions of the learned stimuli. The most effective tolerance to degraded information is presumably achieved in the case of cooperation between the different forms of plasticity. Whether this tolerance to degraded information also applies when the visual input is degraded as a result of a lesion to lower levels of the visual system remains an open question. To address this, we studied visual classification learning in a patient with an extensive bilateral lesion affecting intermediate/low-level visual areas but sparing higher-level areas. Despite difficulty in perceiving the stimuli, the patient learned to classify them, albeit not as quickly as control participants. Moreover, the patient's learning was maintained over the long term and was accompanied by improved discrimination of individual stimuli. These findings demonstrate that degraded output from lesioned, lower areas can be exploited in the service of a new visual task and the results likely implicate a combination of bottom-up and top-down processing during visual learning.

Agnosia↗
PubMed2001

The longitudinal case study: from Schön's model to self-directed learning.

BACKGROUND: Rapid changes observed in information technologies, medical practice, and learning methods encourage physicians to develop new updating strategies. To test its feasibility and to help physicians devise new learning and updating strategies, the knowing-in-action model developed by Schön was applied in planning and evaluating an interactive workshop. Acquisition of knowledge was tested. METHODS: The office and hospital charts of a family physician were reviewed. They were used to prepare a longitudinal case study, based on the real-life story of a hypertensive patient followed by her doctor over a period of 15 years. The clinician's approach to solving clinical problems was triangulated for credibility with general practitioners, specialists, and the information available in the literature. This longitudinal case study was used to develop an interactive educational workshop. The workshop was presented to physicians who had registered in an accredited continuing medical education event. Changes in pre- and postevent knowledge among the participants were assessed using touch pad technology to evaluate the effectiveness of this approach on the acquisition of knowledge related to management of arterial hypertension and associated clinical problems. RESULTS: A comparison of pre- and post-test data showed a significant improvement in knowledge for participants who answered all questions on both questionnaires (n = 8/37). The average score of these participants increased from 5.5 of 10 before the workshop to 8.3 of 10 after the workshop (p < .05). Participants reported a high satisfaction rate for the event. FINDINGS: A workshop using the longitudinal case study enables physicians to perceive their daily practice through a continuing education activity in which they experience the processes of reflection in action and reflection on action described by Schön. It also increases awareness of the gap between current practice and experts' recommendations and provides an opportunity to evaluate the means for bridging or closing this gap. It sensitizes the physician to patients' changing needs and prompts the clinician to reflect on the who, what, when, where, and how of learning.

Education, Medical, Continuing↗
PubMed2006

Focal putamen lesions impair learning in rule-based, but not information-integration categorization tasks.

Previous research on the role of the basal ganglia in category learning has focused on patients with Parkinson's and Huntington's disease, neurodegenerative diseases frequently accompanied by additional cortical pathology. The goal of the present study was to extend this work to patients with basal ganglia lesions due to stroke, asking if similar changes in performance would be observed in patients with more focal pathology. Patients with basal ganglia lesions centered in the putamen (6 left side, 1 right side) were tested on rule-based and information-integration visual categorization tasks. In rule-based tasks, it is assumed that participants can learn the category structures through an explicit reasoning process. In information-integration tasks, optimal performance requires the integration of information from two or more stimulus components, and participants are typically unaware of the category rules. Consistent with previous studies involving patients with degenerative disorders of the basal ganglia, the stroke patients were impaired on the rule-based task, and quantitative, model-based analyses indicate that this deficit was due to the inefficient application of decision strategies. In contrast, the patients were unimpaired on the information-integration task. This pattern of results provides converging evidence supporting a role of the basal ganglia and, in particular, the putamen in rule-based category learning.

Analysis of Variance↗
PubMed1977

Scopolamine induced learning failures in man.

Two experiments were performed to determine the locus of the amnestic effects of scopolamine in man. The first experiment involved 24 volunteers receiving one of three doses of scopolamine (5, 8 or 10 microng/kg) or a placebo, intravenously. The subjects were tested for retention of material learned prior to administration of the drug, acquisition of new information, and retention of material learned while under the influence of the drug. Results indicated that scopolamine has its primary effect on the acquisition of new material and less of an effect on the retrieval of information already learned. The second experiment was designed to refine and expand upon the results of the first and involved 18 volunteers receiving eith 5 or 10 microng/kg of scopolamine or a placebo, intravenously. The subjects were given four trials to learn a list of verbal materials, and their recall for that material was measured at various intervals up to 24 h. These results confirmed those of the first experiment in that the predominant influence of the drug was to impair the acquisition of new information. Implications of these results for memory mechanisms are discussed.

Adult↗