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PubMedDate not supplied

Treating nocturnal enuresis in children: review of evidence.

BACKGROUND: Childhood nocturnal enuresis (bedwetting) affects many families. Although it has a high rate of spontaneous remission, bedwetting may bring social and emotional stigma, stress, and inconvenience to both the child with enuresis and his or her family. DESIGN: Summary of systematic reviews of treatment for nocturnal enuresis in children, published in the Cochrane Library, using evidence only from randomized and quasi-randomized trials to compare interventions. Interventions included behavioral, alarm, and pharmacologic treatments. SETTING AND METHODS: Six Cochrane Reviews contributed evidence to this review: simple behavioral interventions, alarms, complex behavioral or educational interventions, desmopressin, tricyclics and related drugs, and other drugs. SUBJECTS: The participants were children (usually up to the age of 16). RESULTS: Much of the available evidence was of poor quality, and there were few direct comparisons between different types of intervention. Simple behavioral Interventions, such as reward systems, are widely used as standard first-line treatment, but they require a high level of parental involvement. There is currently little evidence to show that these interventions work, but they may be worth trying because they have only a few adverse effects. The use of an alarm intervention reduced nighttime bed wetting in a majority of children both during and after treatment. Overlearning or dry-bed training may reduce the relapse rate. Before embarking on alarm treatment, families need to be made aware of both the time and the high level of parental involvement necessary to attain success. Drug therapy, such as desmopressin and tricyclics, reduced the number of wet nights per week compared with placebo but only while the drug was used. Patients and their families need to be warned about possible side effects of some of the drugs. CONCLUSIONS: Alarms are the most effective treatment for nocturnal enuresis in children, but desmopressin may be considered for temporary relief.

Adolescent↗

PubMed2003

Planning and representing intentional action.

This paper reviews recent approaches to human action planning and the cognitive representation of intentional actions. Evidence suggests that action planning takes place in terms of anticipated features of the intended goal, that is, in terms of action effects. These effects are acquired from early infancy on by registering contingencies between movements and perceptual movement outcomes. Co-occurrence of movements and effects leads to the creation of bidirectional associations between the underlying internal codes, thus establishing distributed perception-action networks subserving both perceiving external events and intentionally producing them. Action plans determine only the general, goal-relevant features of intended actions, while the fine-tuning is left to on-line sensory-motor processing. Action plans emerge from competition for action control between several factors: overlearned habits, perceptual events, and emotional influences, among others. Accordingly, action control represents a balance between personal intentions and wishes on the one hand and environmental affordances and demands on the other.

Animals↗

PubMed2005

Mutation-based genetic neural network.

Evolving gradient-learning artificial neural networks (ANNs) using an evolutionary algorithm (EA) is a popular approach to address the local optima and design problems of ANN. The typical approach is to combine the strength of backpropagation (BP) in weight learning and EA's capability of searching the architecture space. However, the BP's "gradient descent" approach requires a highly computer-intensive operation that relatively restricts the search coverage of EA by compelling it to use a small population size. To address this problem, we utilized mutation-based genetic neural network (MGNN) to replace BP by using the mutation strategy of local adaptation of evolutionary programming (EP) to effect weight learning. The MGNN's mutation enables the network to dynamically evolve its structure and adapt its weights at the same time. Moreover, MGNN's EP-based encoding scheme allows for a flexible and less restricted formulation of the fitness function and makes fitness computation fast and efficient. This makes it feasible to use larger population sizes and allows MGNN to have a relatively wide search coverage of the architecture space. MGNN implements a stopping criterion where overfitness occurrences are monitored through "sliding-windows" to avoid premature learning and overlearning. Statistical analysis of its performance to some well-known classification problems demonstrate its good generalization capability. It also reveals that locally adapting or scheduling the strategy parameters embedded in each individual network may provide a proper balance between the local and global searching capabilities of MGNN.

Algorithms↗

PubMed2006

A bidirectional heteroassociative memory for binary and grey-level patterns.

Typical bidirectional associative memories (BAM) use an offline, one-shot learning rule, have poor memory storage capacity, are sensitive to noise, and are subject to spurious steady states during recall. Recent work on BAM has improved network performance in relation to noisy recall and the number of spurious attractors, but at the cost of an increase in BAM complexity. In all cases, the networks can only recall bipolar stimuli and, thus, are of limited use for grey-level pattern recall. In this paper, we introduce a new bidirectional heteroassociative memory model that uses a simple self-convergent iterative learning rule and a new nonlinear output function. As a result, the model can learn online without being subject to overlearning. Our simulation results show that this new model causes fewer spurious attractors when compared to others popular BAM networks, for a comparable performance in terms of tolerance to noise and storage capacity. In addition, the novel output function enables it to learn and recall grey-level patterns in a bidirectional way.

Algorithms↗

PubMed2004

Dissociating brain regions controlling the temporal and ordinal structure of learned movement sequences.

We used functional magnetic resonance imaging to investigate if different brain regions are controlling the temporal and ordinal structure of movement sequences during performance. Human subjects performed overlearned spatiotemporal sequences of key-presses using the right index finger. Under different conditions, the temporal and the ordinal structure of the sequences were varied systematically in relation to each other, using a factorial design: COMBINED had a rhythm of eight temporal intervals and a serial order of eight keys; TEMPORAL had an eight-interval rhythm produced on one key; ORDINAL had an isochronous rhythm and an eight-key serial order; two control conditions had an isochronous pulse performed on one or two keys, respectively. Brain regions involved in rhythmic and ordinal control of the sequences were revealed by analysing main effect contrasts for the corresponding factors. TEMPORAL and ORDINAL were also compared directly to test for significant differences. A dissociation was found between largely the presupplementary motor area, the right inferior frontal gyrus and precentral sulcus, and the bilateral superior temporal gyri, involved in temporal control, and lateral fronto-parietal areas, the basal ganglia and the cerebellum, which were implicated in ordinal control. The vermis and the superior colliculus were the only regions with an activity increase specifically related to combining long temporal and ordinal sequences. We conclude that humans use different brain networks for temporal and ordinal sequence control, and that the performance of combined sequences activates both networks, the medial cerebellum, and the superior colliculus.

Adolescent↗

PubMed1997

Representations of graphomotor trajectories in the human parietal cortex: evidence for controlled processing and automatic performance.

The aim of this study was to identify the cerebral areas activated during kinematic processing of movement trajectories. We measured regional cerebral blood flow (rCBF) during learning, performance and imagery of right-hand writing in eight right-handed volunteers. Compared with viewing the writing space, increases in rCBF were observed in the left motor, premotor and frontomesial cortex, and in the right anterior cerebellum in all movement conditions, and the increases were related to mean tangential writing velocity. No rCBF increases occurred in these areas during imagery. Early learning of new ideomotor trajectories and deliberately exact writing of letters both induced rCBF increases in the cortex lining the right intraparietal sulcus. In contrast, during fast writing of overlearned trajectories and in the later phase of learning new ideograms the rCBF increased bilaterally in the posterior parietal cortex. Imagery of ideograms that had not been practised previously activated the anterior and posterior parietal areas simultaneously. Our results provide evidence suggesting that the kinematic representations of graphomotor trajectories are multiply represented in the human parietal cortex. It is concluded that different parietal subsystems may subserve attentive sensory movement control and whole-field visuospatial processing during automatic performance.

Adult↗

PubMed1994

Effect of visual experience on locational judgements after perspective change in small-scale space.

Congenitally blind, late blind and blindfold sighted adults overlearned an object-array within a square frame by touch, and judged, facing the midpoint of the frame, the near/far/left/right locations of objects from sides and diagonally from corners. One-half were first guided to points (A-condition), the rest were first asked to imagine themselves as being at points (I-condition). Group and condition did not, but group and observation point did, interact. Lack of visual experience added to RTs and total times and increased errors especially at diagonal stations. Congenitally blind subjects differed from both late blind and blindfold sighted subjects. However, a section of the congenitally blind subjects attained the level of blindfold sighted subjects. The sequence A-I speeded up judgements in all groups. Group did not interact with size of space. Congenitally blind subjects reportedly resorted to holistic representations, but had specific limitations in using them at diagonal stations. Orientation skills of the congenitally blind in far space could be improved by practising perspective taking in near space.

Adult↗

PubMed1991

Do older people know how good they are?

Information and procedures that have been overlearned during a lifetime form a body of 'crystallized' intelligence that is relatively unaffected by ageing. Thus in spite of marked decrements in their 'fluid' memory abilities it is possible that older people may retain knowledge about the limitations and characteristics of their own memory ('metamemory'). To test whether efficiency of metamemory is, indeed, independent of age-related decline in fluid intelligence, 320 people aged from 50 to 79 years were asked to predict their probable performance on four simple memory tasks which had been carefully explained to them. They then experienced the tasks and their predictions were compared with their actual performances. Actual task performance was modestly predicted by chronological age and by AH 4 and Mill Hill IQ test scores but not by subjective self-ratings of everyday memory and cognitive efficiency (the Broadbent CFQ, and the Sunderland & Harris MQ). The data suggest that absolute levels of prediction of performance were associated with self-confidence and were best predicted by scores on the Beck depression scale and by fluid IQ test scores. There was also evidence that individuals with higher test scores gave more accurate as well as more optimistic predictions of their own abilities. Taken together these results suggest that the accuracy of individuals' assessments of their own abilities does alter with age-related changes in fluid IQ, but probably more radically by age-related changes in self-regard and in life-style.

Activities of Daily Living↗

PubMed1983

Retrieval of information from long-term memory.

Information is represented in long-term memory as a network of associations among concepts. Information is retrieved by spreading activation from concepts in working memory through the network structure. The time required to retrieve information is a function of the level of activation that it achieves. Fanning of multiple paths from a node dissipates the activation the node sends down any path and increases retrieval time. Fan effects are reduced as subjects overlearn the material or when they can change their task from a recognition judgment to a consistency judgment.

Face↗

PubMed2003

Organization of action sequences and the role of the pre-SMA.

To understand the contribution of the human presupplementary motor area (pre-SMA) in sequential motor behavior, we performed a series of finger key-press experiments. Experiment 1 revealed that each subject had a spontaneous tendency to organize or "chunk" a long sequence into shorter components. We hypothesized that the pre-SMA might have a special role in initiating each chunk but not at other points during the sequence. Experiment 2 therefore examined the effect of 0.5-s, 10-Hz repetitive transcranial magnetic stimulation (rTMS) directed over the pre-SMA. As hypothesized, performance was disrupted when rTMS was delivered over the pre-SMA at the beginning of the second chunk but not when it was delivered in the middle of a chunk. Contrary to the hypothesis, TMS did not disrupt sequence initiation. Experiments 3 and 4 examined whether the very first movement of a sequence could be disrupted under any circumstances. Pre-SMA TMS did disrupt the initiation of sequences but only when subjects had to switch between sequences and when the first movement of each sequence was not covertly instructed by a learned visuomotor association. In conjunction, the results suggest that for overlearned sequences the pre-SMA is primarily concerned with the initiation of a sequence or sequence chunk and the role of the pre-SMA in sequence initiation is only discerned when subjects must retrieve the sequence from memory as a superordinate set of movements without the aid of a visuomotor association. Control experiments revealed such effects were not present when rTMS was applied over the left dorsal premotor cortex.

Adult↗

PubMed1997

Anatomy of motor learning. I. Frontal cortex and attention to action.

We used positron emission tomography to study new learning and automatic performance in normal volunteers. Subjects learned sequences of eight finger movements by trial and error. In a previous experiment we showed that the prefrontal cortex was activated during new learning but not during during automatic performance. The aim of the present experiment was to see what areas could be reactivated if the subjects performed the prelearned sequence but were required to pay attention to what they were doing. Scans were carried out under four conditions. In the first the subjects performed a prelearned sequence of eight key presses; this sequence was learned before scanning and was practiced until it had become overlearned, so that the subjects were able to perform it automatically. In the second condition the subjects learned a new sequence during scanning. In a third condition the subjects performed the prelearned sequence, but they were required to attend to what they were doing; they were instructed to think about the next movement. The fourth condition was a baseline condition. As in the earlier study, the dorsal prefrontal cortex and anterior cingulate area 32 were activated during new learning, but not during automatic performance. The left dorsal prefrontal cortex and the right anterior cingulate cortex were reactivated when subjects paid attention to the performance of the prelearned sequence compared with automatic performance of the same task. It is suggested that the critical feature was that the subjects were required to attend to the preparation of their responses. However, the dorsal prefrontal cortex and the anterior cingulate cortex were activated more when the subjects learned a new sequence than they were when subjects simply paid attention to a prelearned sequence. New learning differs from the attention condition in that the subjects generated moves, monitored the outcomes, and remembered the responses that had been successful. All these are nonroutine operations to which the subjects must attend. Further analysis is needed to specify which are the nonroutine operations that require the involvement of the dorsal prefrontal and anterior cingulate cortex.

Adult↗

PubMed2003

Spike-driven synaptic dynamics generating working memory states.

The collective behavior of a network, modeling a cortical module of spiking neurons connected by plastic synapses is studied. A detailed spike-driven synaptic dynamics is simulated in a large network of spiking neurons, implementing the full double dynamics of neurons and synapses. The repeated presentation of a set of external stimuli is shown to structure the network to the point of sustaining working memory (selective delay activity). When the synaptic dynamics is analyzed as a function of pre- and postsynaptic spike rates in functionally defined populations, it reveals a novel variation of the Hebbian plasticity paradigm: in any functional set of synapses between pairs of neurons (e.g., stimulated-stimulated, stimulated-delay, stimulated-spontaneous), there is a finite probability of potentiation as well as of depression. This leads to a saturation of potentiation or depression at the level of the ratio of the two probabilities. When one of the two probabilities is very high relative to the other, the familiar Hebbian mechanism is recovered. But where correlated working memory is formed, it prevents overlearning. Constraints relevant to the stability of the acquired synaptic structure and the regimes of global activity allowing for structuring are expressed in terms of the parameters describing the single-synapse dynamics. The synaptic dynamics is discussed in the light of experiments observing precise spike timing effects and related issues of biological plausibility.

Action Potentials↗

PubMed2004

Robustifying AdaBoost by adding the naive error rate.

AdaBoost can be derived by sequential minimization of the exponential loss function. It implements the learning process by exponentially reweighting examples according to classification results. However, weights are often too sharply tuned, so that AdaBoost suffers from the nonrobustness and overlearning. Wepropose a new boosting method that is a slight modification of AdaBoost. The loss function is defined by a mixture of the exponential loss and naive error loss functions. As a result, the proposed method incorporates the effect of forgetfulness into AdaBoost. The statistical significance of our method is discussed, and simulations are presented for confirmation.

Algorithms↗

PubMed2006

Classical conditioned responses to absent tones.

BACKGROUND: Recent evidence for a tight coupling of sensorimotor processes in trained musicians led to the question of whether this coupling extends to preattentively mediated reflexes; particularly, whether a classically conditioned response in one of the domains (auditory) is generalized to another (tactile/motor) on the basis of a prior association in a second-order Pavlovian paradigm. An eyeblink conditioning procedure was performed in 17 pianists, serving as a model for overlearned audiomotor integration, and 14 non-musicians. RESULTS: During the training session, subjects were conditioned to respond to auditory stimuli (piano tones). During a subsequent testing session, when subjects performed keystrokes on a silent piano, pianists showed significantly higher blink rates than non-musicians. CONCLUSION: These findings suggest a tight coupling of the auditory and motor domains in musicians, pointing towards training-dependent mechanisms of strong cross-modal sensorimotor associations even on sub-cognitive processing levels.

Acoustic Stimulation↗

PubMed2002

Fluency in multiple sclerosis: which measure is best?

Tests of verbal fluency provide brief and sensitive measures of the deficits in rapidly retrieving overlearned information common in multiple sclerosis (MS). Production of words that begin with the letters F, A, and S is the verbal fluency measure most often used with patients who are fluent in English. However, because of frequency of words beginning with certain letters varies from one language to another, it is unlikely that any fixed set of letters will be appropriate for multicenter trials that involve patients who are fluent in different languages. A possible alternative involves using semantic fluency categories that contain such a large number of exemplars that no fluent speaker of any language could exhaust the category in the allotted response time. To examine the potential usefulness of semantic fluency measures, 203 MS patients and 87 healthy controls generated words that begin with F, A, or S or were exemplars of the categories animals and parts of the body. Receiver operating characteristic (ROC) curve analyses indicated that sensitivities and specificities for the three fluency measures in discriminating patients from controls were quite similar, especially if patients with global cognitive impairment were excluded.

Adult↗

PubMed2005

Mindfulness-based parent training: strategies to lessen the grip of automaticity in families with disruptive children.

Disagreements and conflicts in families with disruptive children often reflect rigid patterns of behavior that have become overlearned and automatized with repeated practice. These patterns are mindless: They are performed with little or no awareness and are highly resistant to change. This article introduces a new, mindfulness-based model of parent training and contrasts the model's assumptions with those of behavioral (operant) parent training. The new model informs 3 strategies to lessen the grip of automaticity in families with disruptive children: facilitative listening, distancing, and motivated action plans. The article does not oppose mindfulness to mindlessness or suggest that the former is always better than the latter but instead proposes that each is most useful at different times in the parenting process. I conclude by calling for empirical investigations of mindfulness-based parent training and, if those are successful, for the development of an integrated model that blends behavioral and mindfulness-based principles to inform all facets of intervention.

Adult↗

PubMed2006

Cortical plasticity and motor activity studied with transcranial magnetic stimulation.

For decades cortical representations of the parts of the body have been considered to be unchangeable. This view has changed radically during the past 20 years using new tools designed to study plasticity in the adult human brain. Transcranial magnetic stimulation (TMS) is a valuable non-invasive technique for exploring the ability of the motor cortex to change during motor skill acquisition. Results obtained with TMS in neurological patients as well as in normal subjects demonstrate that cortical plasticity is a necessity for correct adaptation to the continuously changing environment. Topographical reorganization of the motor cortex depends on the types of movements performed by the subjects. During simple training, the cortical representation is enlarged, and it returns to its initial size when the task is overlearned. These transient modifications characterize simple motor training. Motor skills in which coordination of distal and proximal muscles, precision of the task and spatio-temporal constraints are associated, has a different impact on cortical reorganization. We propose that years of practice of a complex motor skill induces a new cortical topography that must be interpreted as structural plasticity which provides the capacity to execute a plastic behaviour instead of a stereotypical movement. We review the neuronal mechanisms underlying plasticity in different types of movement. We stress new emerging notions, such as overlap of cortical maps, and system dynamics at single neuron and network levels, to explain the reorganization of movement representations that encode motor skill. Dendritic arborizations as functional computing elements, newly generated neurons in adult brain, and plastic architectures of cortical networks operating as distributed functional modules are new hypotheses for structural plasticity.

Adaptation, Physiological↗

PubMed2002

Information processing of pictograms and the visual field difference.

The main purpose was to investigate how we process pictograms and to examine the effects of learning on visual field differences when participants overlearn the meaning of each pictogram. 15 students were required to judge whether the referent of each symbol was either larger or smaller than the referent of the standard stimulus (Test 1). Several days later the same task was conducted (Test 2). Although a right visual field advantage was observed in Test 1, it was not apparent at Test 2 after participants had studied the pictogram list repeatedly. These results suggest that pictograms might be processed in much the same way as other ordinary verbal stimuli at a very early stage of learning. Participants could, however, comprehend the pictograms by employing a kind of imagery processing after they were familiar with the symbols.

Adolescent↗