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PubMedDate not supplied

Women's experiences of abnormal cervical cytology: illness representations, care processes, and outcomes.

BACKGROUND: We wanted to explore the conceptual representations of illness and experiences with care among women who have learned of an abnormal Papanicolaou (Pap) smear result. METHODS: The study took place in 2 primary care, family practice clinics serving low-income, multiethnic patients in the Bronx, New York City. We conducted qualitative, semistructured telephone interviews with 17 patients who had recently learned of abnormal findings on a Pap smear. After a preliminary coding phase, the investigators identified 2 important outcomes: distress and dissatisfaction with care, and factors affecting these outcomes. A model was developed on a subset of the data, which was then tested on each transcript with an explicit search for disconfirming cases. A revised coding scheme conforming to the dimensions of the model was used to recode transcripts. RESULTS: Women reported complex, syncretic models of illness that included both biomedical and folk elements. Many concerns, especially nonbiomedical concerns, were not addressed in interactions with physicians. An important source of both distress and dissatisfaction with care was the women's lack of understanding of the inherent ambiguity of Pap smear results. When perceived care needs, which included emotional support as well as information, were not met, distress and dissatisfaction were greatly increased. CONCLUSION: In this study, patients' illness models and expectations of care were not routinely addressed in their conversations with physicians about abnormal Pap smear results. When physicians can take the time to review patients' illness models carefully, distress and dissatisfaction with care can be reduced considerably.

Adult↗
PubMed1997

XBONE: a hybrid expert system for supporting diagnosis of bone diseases.

In this paper, XBONE, a hybrid medical expert system that supports diagnosis of bone diseases is presented. Diagnosis is based on various patient data and is performed in two stages. In the early stage, diagnosis is based on demographic and clinical data of the patient, whereas in the late stage it is mainly based on nuclear medicine image data. Knowledge is represented via an integrated formalism that combines production rules and the Adaline artificial neural unit. Each condition of a rule is assigned a number, called its significance factor, representing its significance in drawing the conclusion of the rule. This results in better representation, reduction of the knowledge base size and gives the system learning capabilities.

Bone Diseases↗
PubMedDate not supplied

Nature of phonological delay in children with specific language impairment.

This study investigated the nature of phonological delay in a group of children with specific language impairment. It was asked whether phonological errors in this group of children were generated by a slow but normal language learning process or whether they reflected a selective impairment in some representations that enhance normal acquisition and use of a language phonology. A group of 10 children with SLI (mean age = 5.1) was compared with three groups of normal children who were matched in age (age control group, mean age = 5.1), in sentence comprehension and recalling (grammar control group, mean age = 3.7), or who exhibited a phonological performance lower than the age average (group with low phonological performance, mean age = 4.4). The four groups of children were assessed in terms of: (1) responses to a mispronunciation detection task; and (2) error profiles with complex and simple syllabic structures. Performance on the mispronunciation detection task showed that the group with SLI could distinguish a target lexical item from acoustic non-word stimuli that were highly similar to it in terms of phonetic characteristics. An analysis of overall error rate at this task showed, however, that four children with SLI had a much lower performance than normal children of the same age, even when the auditory stimuli were tokens of the target word, or non-words that were phonetically different from the target. A difficulty in coordinating vocal actions in an articulatory plan accounted for error profiles with simple syllabic structures both for some children with SLI and normal children with phonological performance lower than the age average. A severe difficulty with representing complex syllabic structures was a homogeneous characteristic of the group with SLI and worked as the main indicator of impaired, rather than simply slow, phonological development.

Articulation Disorders↗
PubMed1990

Artificial neural networks and their use in quantitative pathology.

A brief general introduction to artificial neural networks is presented, examining in detail the structure and operation of a prototype net developed for the solution of a simple pattern recognition problem in quantitative pathology. The process by which a neural network learns through example and gradually embodies its knowledge as a distributed representation is discussed, using this example. The application of neurocomputer technology to problems in quantitative pathology is explored, using real-world and illustrative examples. Included are examples of the use of artificial neural networks for pattern recognition, database analysis and machine vision. In the context of these examples, characteristics of neural nets, such as their ability to tolerate ambiguous, noisy and spurious data and spontaneously generalize from known examples to handle unfamiliar cases, are examined. Finally, the strengths and deficiencies of a connectionist approach are compared to those of traditional symbolic expert system methodology. It is concluded that artificial neural networks, used in conjunction with other nonalgorithmic artificial intelligence techniques and traditional algorithmic processing, may provide useful software engineering tools for the development of systems in quantitative pathology.

Artificial Intelligence↗
PubMed2003

Interactions of the hippocampal system and the prefrontal cortex in learning language-like rules.

One of the most influential views on the hippocampal function suggests that this brain region is critically involved in relational memory processing, that is, binding converging inputs to mediate the representation of relationships among the constituents of episodes. It has been proposed that this binding is automatic and obligatory during learning and remembering In addition, neuroimaging studies have highlighted the importance of the prefrontal cortex, in learning, memory, and language processing. However, the posited importance of hippocampal-prefrontal interaction remains to be empirically tested. In the present study we used functional magnetic resonance imaging to examine in detail this interaction by assessing learning-related changes in hemodynamic activity during artificial language acquisition. It has been shown previously that artificial grammar systems might be learned by evaluating pattern-based relations in word sequences and generalizing beyond specific word order, that is, rule abstraction. During scanning, participants learned an artificial language whose miniature grammar meets the universal principles of a natural language. Increased proficiency level of the artificial language is associated with decreased left hippocampal activity. In contrast, we observed an increased recruitment of the left inferior frontal gyrus (Broca's area), a region that contributes to syntax processing in natural language. The present results, therefore, indicate a learning-related change in brain circuitry underlying relational processes of language learning, with a transition from a similarity-based learning system in the medial temporal lobes to a language-related processing system in the left prefrontal cortex.

Adult↗
PubMed2001

Theoretical perspectives on language and communication problems in mental retardation and developmental disabilities.

We argue that researchers interested in language and communication problems in mental retardation or any other developmental disorder should view such problems as emerging within the broader context of the behavioral profile, or phenotype, associated with a particular genetic condition. This will require understanding the direct and indirect effects of genes on the development of language and communication and thereby an understanding of the complex relations that exist between language and other dimensions of psychological and behavioral functioning as well as an understanding of the environments in which the developing person acts and is acted upon. We believe that the dominant model for understanding language and communication problems--the nativist approach, which emphasizes the child's innate capacity for acquiring language and characterizes language as consisting of a set of context-free deterministic rules that operate on abstract representations--is inconsistent with an emphasis on indirect genetic effects. We review recent evidence that undermines the nativist approach--evidence concerning the initial state of the language-learning child, the role of environmental input, the competence-performance distinction, and modularity. In place of nativism, we argue for Emergentism, which is a model in which language is seen to emerge from the interaction between the child's biological abilities to map statistical properties of the language input into a distributed representation and the characteristics of the language learning environment and for the purpose of engaging in real-time, meaningful language use.

Child↗
PubMed2005

Opponent appetitive-aversive neural processes underlie predictive learning of pain relief.

Termination of a painful or unpleasant event can be rewarding. However, whether the brain treats relief in a similar way as it treats natural reward is unclear, and the neural processes that underlie its representation as a motivational goal remain poorly understood. We used fMRI (functional magnetic resonance imaging) to investigate how humans learn to generate expectations of pain relief. Using a pavlovian conditioning procedure, we show that subjects experiencing prolonged experimentally induced pain can be conditioned to predict pain relief. This proceeds in a manner consistent with contemporary reward-learning theory (average reward/loss reinforcement learning), reflected by neural activity in the amygdala and midbrain. Furthermore, these reward-like learning signals are mirrored by opposite aversion-like signals in lateral orbitofrontal cortex and anterior cingulate cortex. This dual coding has parallels to 'opponent process' theories in psychology and promotes a formal account of prediction and expectation during pain.

Avoidance Learning↗
PubMed1986

Differential effects of posterior septal lesions on dispositional and representational memory.

A distinction between two classes of memory has been made in terms of the sensory availability of cues at the time of making discriminations which are influenced by past experience. Three tasks objectively defining this distinction were learned in a T-maze by three groups of rats: a delayed nonmatching-to-sample (DNMTS) which depends on representational memory; a simple sensory discrimination (SD) which depends on dispositional memory; and a more difficult discrimination, which also depends on dispositional memory, called the simultaneous conditional discrimination (SCD). The DNMTS and SD tasks were acquired quickly; the SCD task took many more trials. Posterior septal lesions impaired DNMTS performance but had no effect on retention of either the conditional discrimination (SCD) or the simple sensory discrimination (SD) tasks which depend on dispositional memory. The present study provides further evidence that dispositional and representational memory systems have at least partially distinct anatomical substrates in the brain and that it is the representational and not the conditional aspects of the DNMTS task that are impaired by the septal lesions.

Animals↗
PubMed1996

An analysis of errors in the learning, overlearning, and forgetting of sequences.

This paper investigates the effects upon delayed recall of errors made during learning. Subjects learn a sequence of wagons in a model train over repeated presentation and test cycles. The recall of the same sequence is unexpectedly tested one week later. The results show that the errors subjects make during learning are a significant factor in predicting which elements of the sequence are forgotten. Learning is modelled by a population of discrete traces, accumulated during learning, which has two characteristics: First, many of the traces duplicate information encoded in other traces; and second, representations of the correct sequence coexist with traces containing incorrect information about the same elements of the sequence. Forgetting is modelled by the accretion of null traces that compete with correct traces of retrieval and the increasing inability with time to discriminate correct representations in memory from erroneous records. This model is shown to provide a good fit to the experimental results and suggests a strong link between the complete history of learning new material (including errors) and its subsequent likelihood of forgetting.

Attention↗
PubMed2005

Taste, olfactory, and food texture processing in the brain, and the control of food intake.

Complementary neurophysiological recordings in macaques and functional neuroimaging in humans show that the primary taste cortex in the rostral insula and adjoining frontal operculum provides separate and combined representations of the taste, temperature, and texture (including viscosity and fat texture) of food in the mouth independently of hunger and thus of reward value and pleasantness. One synapse on, in the orbitofrontal cortex, these sensory inputs are for some neurons combined by learning with olfactory and visual inputs. Different neurons respond to different combinations, providing a rich representation of the sensory properties of food. In the orbitofrontal cortex, feeding to satiety with one food decreases the responses of these neurons to that food, but not to other foods, showing that sensory-specific satiety is computed in the primate (including human) orbitofrontal cortex. Consistently, activation of parts of the human orbitofrontal cortex correlates with subjective ratings of the pleasantness of the taste and smell of food. Cognitive factors, such as a word label presented with an odour, influence the pleasantness of the odour, and the activation produced by the odour in the orbitofrontal cortex. These findings provide a basis for understanding how what is in the mouth is represented by independent information channels in the brain; how the information from these channels is combined; and how and where the reward and subjective affective value of food is represented and is influenced by satiety signals. Activation of these representations in the orbitofrontal cortex may provide the goal for eating, and understanding them helps to provide a basis for understanding appetite and its disorders.

Animals↗
PubMed2006

Brain mechanisms underlying flavour and appetite.

Complementary neurophysiological recordings in macaques and functional neuroimaging in humans show that the primary taste cortex in the rostral insula and adjoining frontal operculum provides separate and combined representations of the taste, temperature and texture (including viscosity and fat texture) of food in the mouth independently of hunger and thus of reward value and pleasantness. One synapse on, in the orbitofrontal cortex, these sensory inputs are for some neurons combined by learning with olfactory and visual inputs. Different neurons respond to different combinations, providing a rich representation of the sensory properties of food. In the orbitofrontal cortex, feeding to satiety with one food decreases the responses of these neurons to that food, but not to other foods, showing that sensory-specific satiety is computed in the primate (including human) orbitofrontal cortex. Consistently, activation of parts of the human orbitofrontal cortex correlates with subjective ratings of the pleasantness of the taste and smell of food. Cognitive factors, such as a word label presented with an odour, influence the pleasantness of the odour and the activation produced by the odour in the orbitofrontal cortex. These findings provide a basis for understanding how what is in the mouth is represented by independent information channels in the brain; how the information from these channels is combined; and how and where the reward and subjective affective value of food is represented and is influenced by satiety signals. Activation of these representations in the orbitofrontal cortex may provide the goal for eating, and understanding them helps to provide a basis for understanding appetite and its disorders.

Animals↗
PubMedDate not supplied

The basal ganglia and chunking of action repertoires.

The basal ganglia have been shown to contribute to habit and stimulus-response (S-R) learning. These forms of learning have the property of slow acquisition and, in humans, can occur without conscious awareness. This paper proposes that one aspect of basal ganglia-based learning is the recoding of cortically derived information within the striatum. Modular corticostriatal projection patterns, demonstrated experimentally, are viewed as producing recoded templates suitable for the gradual selection of new input-output relations in cortico-basal ganglia loops. Recordings from striatal projection neurons and interneurons show that activity patterns in the striatum are modified gradually during the course of S-R learning. It is proposed that this recoding within the striatum can chunk the representations of motor and cognitive action sequences so that they can be implemented as performance units. This scheme generalizes Miller's notion of information chunking to action control. The formation and the efficient implementation of action chunks are viewed as being based on predictive signals. It is suggested that information chunking provides a mechanism for the acquisition and the expression of action repertoires that, without such information compression would be biologically unwieldy or difficult to implement. The learning and memory functions of the basal ganglia are thus seen as core features of the basal ganglia's influence on motor and cognitive pattern generators.

Animals↗
PubMed2005

UML as a cell and biochemistry modeling language.

The systems biology community is building increasingly complex models and simulations of cells and other biological entities, and are beginning to look at alternatives to traditional representations such as those provided by ordinary differential equations (ODE). The lessons learned over the years by the software development community in designing and building increasingly complex telecommunication and other commercial real-time reactive systems, can be advantageously applied to the problems of modeling in the biology domain. Making use of the object-oriented (OO) paradigm, the unified modeling language (UML) and Real-Time Object-Oriented Modeling (ROOM) visual formalisms, and the Rational Rose RealTime (RRT) visual modeling tool, we describe a multi-step process we have used to construct top-down models of cells and cell aggregates. The simple example model described in this paper includes membranes with lipid bilayers, multiple compartments including a variable number of mitochondria, substrate molecules, enzymes with reaction rules, and metabolic pathways. We demonstrate the relevance of abstraction, reuse, objects, classes, component and inheritance hierarchies, multiplicity, visual modeling, and other current software development best practices. We show how it is possible to start with a direct diagrammatic representation of a biological structure such as a cell, using terminology familiar to biologists, and by following a process of gradually adding more and more detail, arrive at a system with structure and behavior of arbitrary complexity that can run and be observed on a computer. We discuss our CellAK (Cell Assembly Kit) approach in terms of features found in SBML, CellML, E-CELL, Gepasi, Jarnac, StochSim, Virtual Cell, and membrane computing systems.

Algorithms↗
PubMed2007

Free-lunch learning: modeling spontaneous recovery of memory.

After a language has been learned and then forgotten, relearning some words appears to facilitate spontaneous recovery of other words. More generally, relearning partially forgotten associations induces recovery of other associations in humans, an effect we call free-lunch learning (FLL). Using neural network models, we prove that FLL is a necessary consequence of storing associations as distributed representations. Specifically, we prove that (1) FLL becomes increasingly likely as the number of synapses (connection weights) increases, suggesting that FLL contributes to memory in neurophysiological systems, and (2) the magnitude of FLL is greatest if inactive synapses are removed, suggesting a computational role for synaptic pruning in physiological systems. We also demonstrate that FLL is different from generalization effects conventionally associated with neural network models. As FLL is a generic property of distributed representations, it may constitute an important factor in human memory.

Association↗
PubMed1999

The role of nucleus accumbens dopamine in motivated behavior: a unifying interpretation with special reference to reward-seeking.

Studies addressing behavioral functions of dopamine (DA) in the nucleus accumbens septi (NAS) are reviewed. A role of NAS DA in reward has long been suggested. However, some investigators have questioned the role of NAS DA in rewarding effects because of its role in aversive contexts. As findings supporting the role of NAS DA in mediating aversively motivated behaviors accumulate, it is necessary to accommodate such data for understanding the role of NAS DA in behavior. The aim of the present paper is to provide a unifying interpretation that can account for the functions of NAS DA in a variety of behavioral contexts: (1) its role in appetitive behavioral arousal, (2) its role as a facilitator as well as an inducer of reward processes, and (3) its presently undefined role in aversive contexts. The present analysis suggests that NAS DA plays an important role in sensorimotor integrations that facilitate flexible approach responses. Flexible approach responses are contrasted with fixed instrumental approach responses (habits), which may involve the nigro-striatal DA system more than the meso-accumbens DA system. Functional properties of NAS DA transmission are considered in two stages: unconditioned behavioral invigoration effects and incentive learning effects. (1) When organisms are presented with salient stimuli (e.g., novel stimuli and incentive stimuli), NAS DA is released and invigorates flexible approach responses (invigoration effects). (2) When proximal exteroceptive receptors are stimulated by unconditioned stimuli, NAS DA is released and enables stimulus representations to acquire incentive properties within specific environmental context. It is important to make a distinction that NAS DA is a critical component for the conditional formation of incentive representations but not the retrieval of incentive stimuli or behavioral expressions based on over-learned incentive responses (i.e., habits). Nor is NAS DA essential for the cognitive perception of environmental stimuli. Therefore, even without normal NAS DA transmission, the habit response system still allows animals to perform instrumental responses given that the tasks take place in fixed environment. Such a role of NAS DA as an incentive-property constructor is not limited to appetitive contexts but also aversive contexts. This dual action of NAS DA in invigoration and incentive learning may explain the rewarding effects of NAS DA as well as other effects of NAS DA in a variety of contexts including avoidance and unconditioned/conditioned increases in open-field locomotor activity. Particularly, the present hypothesis offers the following interpretation for the finding that both conditioned and unconditioned aversive stimuli stimulate DA release in the NAS: NAS DA invigorates approach responses toward 'safety'. Moreover, NAS DA modulates incentive properties of the environment so that organisms emit approach responses toward 'safety' (i.e., avoidance responses) when animals later encounter similar environmental contexts. There may be no obligatory relationship between NAS DA release and positive subjective effects, even though these systems probably interact with other brain systems which can mediate such effects. The present conceptual framework may be valuable in understanding the dynamic interplay of NAS DA neurochemistry and behavior, both normal and pathophysiological.

Animals↗
PubMedDate not supplied

Children with mathematics learning disabilities in Belgium.

In Belgium, between 3% and 8% of the children in elementary schools have mathematics learning disabilities (MLD). Many of these children have less developed linguistic, procedural, and mental representation skills. Moreover, a majority of the children have been found to show inaccurate prediction and evaluation skills in Grade 3. MLD often become obvious in elementary school. Whereas some children are retained, others are referred to special education. During the last 10 years, the number of children in special education and the number of children with learning disabilities who are following a special guidance program in general education (inclusive education) have increased. Children in Belgium with MLD can get therapy for about 2 years. Nevertheless, many problems continue unresolved even in high school and adulthood.

Belgium↗
PubMed2006

Recency effects as a window to generalization: separating decisional and perceptual sequential effects in category learning.

Accounts of learning and generalization typically focus on factors related to lasting changes in representation (i.e., long-term memory). The authors present evidence that shorter term effects also play a critical role in determining performance and that these recency effects can be subdivided into perceptual and decisional components. Experimental results based on a probabilistic category structure show that the previous stimulus exerts a contrastive effect on the current percept (perceptual recency) and that responses are biased toward or away from the previous feedback, depending on the similarity between successive stimuli (decisional recency). A method for assessing these recency effects is presented that clarifies open questions regarding stimulus generalization and perceptual contrast effects in categorization and in other domains.

Attention↗
PubMed2000

Use of scheme-based problem solving: an evaluation of the implementation and utilization of schemes in a clinical presentation curriculum.

CONTEXT: The University of Calgary has implemented a new curriculum which is organized according to 120 ways in which patients may present to a physician. Students are taught scheme-based problem solving rather than the more typical hypothetico-deductive or search and scan approach to problem resolution. OBJECTIVE: This study sought to determine the extent to which faculty and students were implementing and utilizing scheme-based problem solving. METHOD: All classes taught within the new clinical presentation curriculum were surveyed at the year end. Participants included four classes of first-year students and three classes of second-year students. Using a 5-point scale, students responded to survey items regarding scheme implementation and utilization. RESULTS: Data were analysed using MANOVA (multivariate analysis of variance) and revealed significant differences among classes in both first- and second-year students. Increments in scheme implementation and utilization by instructors and students were observed, although instructors' utilization of schemes lagged behind that of students. A levelling effect to the benefits of schemes for problem solving was also evident. First-year students reported schemes to be very useful for learning and organizing new information. CONCLUSION: Although it has taken time to implement curriculum change, the student response to schemes has been favourable. Faculty development and further generation of pictorial/spatial representations for all schemes, to ensure that all clinical presentations provide pathways that students can use for both learning and problem solving are recommended. Whether students who utilize schemes are more successful problem solvers is not yet known but will be the subject of study as soon as scheme delivery is predominant.

Adult↗