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Views, behaviours and perceived staff development needs of doctors and surgeons regarding learners in outpatient clinics.

INTRODUCTION: The need to use outpatient clinics as a major learning environment in hospitals for students and doctors-in-training is clear. However, consultant supervisors perceive major barriers to this and continue to rely heavily on traditional inpatient learning. This quantitative study examines what approaches consultant supervisors employ in outpatient learning, together with what they perceive themselves to use and what they would value in further training. METHODS: We observed learning episodes for students and doctors-in-training in medical and surgical clinics. A questionnaire on outpatient teaching was also sent to consultant doctors and surgeons. This was based on these observations and focus groups with students and doctors-in-training. RESULTS: There was an overall survey response rate of 62% (194/311). The dominant forms of learning we observed were 'arms-length' supervision for doctors-in-training and 'modelling' for students. Only 7% of learning episodes involved a doctor-in-training doing something under direct supervision. In contrast to the observation results, consultants considered that students and doctors-in-training received a lot of direct supervision and interaction. For example, 45% considered that doctors-in-training 'may see patients with me in a joint consultation'. Only 30% of respondents would be interested in staff development in learning in outpatient clinics. CONCLUSIONS: Although consultants reported that they frequently used an active approach to learning in outpatient clinics, modelling was used predominantly for students and arms-length supervision was used for doctors-in-training.

Ambulatory Care↗

Improving vision in adult amblyopia by perceptual learning.

Practicing certain visual tasks leads, as a result of a process termed "perceptual learning," to a significant improvement in performance. Learning is specific for basic stimulus features such as local orientation, retinal location, and eye of presentation, suggesting modification of neuronal processes at the primary visual cortex in adults. It is not known, however, whether such low-level learning affects higher-level visual tasks such as recognition. By systematic low-level training of an adult visual system malfunctioning as a result of abnormal development (leading to amblyopia) of the primary visual cortex during the "critical period," we show here that induction of low-level changes might yield significant perceptual benefits that transfer to higher visual tasks. The training procedure resulted in a 2-fold improvement in contrast sensitivity and in letter-recognition tasks. These findings demonstrate that perceptual learning can improve basic representations within an adult visual system that did not develop during the critical period.

Adult↗

Policy windows, policy change, and organizational learning: watersheds in the evolution of watershed management.

Employing in-depth, elite interviews, this empirical research contributes to understanding the dynamics among policy windows, policy change, and organizational learning. First, although much of the research on agenda setting-how issues attract enough attention that action is taken to address them-has been conducted at the national scale, this work explores the subnational, regional scale. With decentralization, regional-scale environmental decision-making has become increasingly important. Second, this research highlights the role of policy windows and instances of related organizational learning identified by natural resources managers. Having practitioners identify focusing events contrasts with the more typical approach of the researcher identifying a particular focusing event or events to investigate. A focusing event is a sudden, exceptional experience that, because of how it leads to harm or exposes the prospect for great devastation, is perceived as the impetus for policy change.

Conservation of Natural Resources↗

Artificial neural networks for predictive modeling in prostate cancer.

Artificial neural networks (ANNs) represent a relatively new methodology for predictive modeling in medicine. ANNs, a form of artificial intelligence loosely based on the brain, have a demonstrated ability to learn complex and subtle relationships between variables in medical applications. In contrast with traditional statistical techniques, ANNs are capable of automatically resolving these relationships without the need for a priori assumptions about the nature of the interactions between variables. As with any technique, ANNs have limitations and potential drawbacks. This article provides an overview of the theoretical basis of ANNs, how they function, their strengths and limitations, and examples of how ANNs have been used to develop predictive models for the management of prostate cancer.

Diagnosis, Differential↗

Long-term effects of nerve growth factor and neural transplants on behavior of rats with medial septal lesions.

The present experiment investigated the interaction between exogenous nerve growth factor (NGF) and intrahippocampal septal grafts on the behavior of rats after a medial septum lesion. Young female rats received a bilateral injection of a fetal septal cell suspension into the dorsal hippocampus either immediately (immediate grafts) or 8 days after the lesion (delayed grafts). For delayed grafts, a higher concentration of endogenous neurotrophic factors can be assumed to be present in the deafferentated host tissue at the time of transplantation. One group of rats with lesions received NGF with the immediate grafts, another group received NGF alone. A sham-operated group and 3 groups with lesions (and given either immediate or delayed intrahippocampal saline injections, or no other treatment) constituted controls. The animals were tested for spontaneous alternation and for performance in a radial 8-arm maze, 1, 5 and 9 months postoperatively. Medial septal lesions reduced spontaneous alternation but, 9 months after surgery, recovery was observed in both lesion-control rats and in rats with delayed grafts (but not with immediate grafts). In the radial maze task, lesions produced a persistent impairment, although both immediate and delayed grafts reduced this deficit several months after surgery (more markedly and rapidly in the case of delayed grafts). NGF, however, increased the maze learning deficit especially 5 months postoperatively. These latter results are in contrast to findings of earlier studies showing transient beneficial effects of NGF administration. It is suggested that the effects of NGF in the present study might be due to an enhanced sprouting of sympathetic fibers into the hippocampal formation.

Animals↗

Descending antinociceptive mechanisms in the brainstem: their role in the animal's defensive system.

The identification of specialized mechanisms in the mammalian brainstem that function to inhibit the rostral transmission of nociceptive (pain-related) information in the spinal cord led to an explosion of research into the neuroanatomical and neurochemical substrates of these antinociceptive systems. As outlined in the present paper, most attention was directed at those mechanisms in the periaqueductal grey (PAG) and rostral ventromedial medulla (RVM). However, comparatively little attention has been paid to the functional role of these mechanisms in animal behaviour. The purpose of the present paper is to review research into the behavioural significance of those antinociceptive mechanisms in the PAG and RVM. It is concluded that these mechanisms function as part of the animal's fear or defensive system, serving to make a threatened animal insensitive to noxious stimulation and thereby allowing that animal to engage in defensive responses instead of recuperative activities. Further, it is argued that the organization of these antinociceptive circuits reflects the animal's increasing capacity for early detection of danger. Specifically, nociception itself is held to signify the presence of immediate threat, and consequently, nociceptive input directly activates antinociceptive circuits at either the spinal level (during intense noxious stimulation) or RVM (following exposure to moderate noxious stimuli). In contrast, events that are themselves innocuous but which signal threat (either learned or innate danger signals) activate fear and defensive systems in the amygdala and PAG which engage the descending antinociceptive projections in the RVM.

Aggression↗

Therapeutic modulation of synaptic connectivity with desynchronizing brain stimulation.

In a modeling study, we show that synaptic connectivity can effectively be reshaped by an appropriate modulation of neuronal dynamics. To this end, we incorporate synaptic plasticity with symmetric spike-timing characteristics into a population of bursting neurons, which are interacting via chemical synapses. Under spontaneous conditions, qualitatively different stable dynamical states may coexist. We observe states characterized either by pathological synchrony or by uncorrelated activity. Suitably designed stimulation protocols enable to shift the neuronal population from one dynamical state to another. Due to low-frequency periodic pulse train stimulation, the population learns pathologically strong interactions, as known from the kindling phenomenon. In contrast, desynchronizing stimulation, e.g., multi-site coordinated reset stimulation, enables the network to unlearn pathologically strong synaptic interactions, so that a powerful long-term anti-kindling is achieved. We demonstrate that anti-kindling can be achieved even with weak and/or short desynchronizing stimuli, which are not able to cause a complete desynchronization in the course of the stimulation. Our results show that desynchronizing stimulation may serve as a novel curative approach for the therapy of neurological diseases connected with pathological cerebral synchrony.

Algorithms↗

Impaired self-initiated task preparation during task switching in Parkinson's disease.

Patients with Parkinson's disease (PD) typically show reduced performance in clinical tests involving cognitive control processes, presumably due to reduced availability of dopamine in striatofrontal neuronal circuits. Although task switching paradigms are considered as an ideal experimental measure of cognitive control, previous studies on task switching in PD have yielded ambiguous results, indicating that performance deficits depend on the specific task requirements. Among these, the aspect of self-initiated as opposed to externally triggered task preparation seems to play an important role, as evidenced by recent research. To address this topic, the present study investigated PD patients and age-matched controls (n=16) with a sequential switching task in which the upcoming task was predicted by two different types of cues. Firstly, every task was predicted by an external visual cue of varying utility (long versus short precuing interval). Additionally, the tasks were predictable on the basis of a fixed task sequence (AABB), which placed relatively higher demands on self-initiated task preparation. After considerable practice, the sequence was changed to random. Increased reaction times following sequence removal indicated prior use of the sequence in both groups. However, in contrast to healthy age-matched controls, PD patients did not learn to use the predictable task sequence to a greater extent when the utility of the visual task cue was low due to a short precuing interval. This finding is interpreted as evidence for a specific impairment in self-initiated as opposed to externally triggered task preparation.

Aged↗

Extensive cytotoxic lesions involving both the rhinal cortices and area TE impair recognition but spare spatial alternation in the rat.

Rats with cytotoxic lesions of the perirhinal, postrhinal, and TE cortices (Rh+TE, n = 7) were compared with surgical control animals (n = 7) on a series of spontaneous object recognition tests. The Rh+TE group was associated with a failure to select the novel object. This recognition deficit contrasted with the apparently normal ability of the same animals to learn and perform a spatial working memory test (T-maze alternation). The animals were also tested on the acquisition of an automated visual discrimination task in which the stimuli were presented on a visual display unit (VDU) equipped with a touch screen. The animals with Rh+TE lesions showed only a borderline deficit on this task. These findings are consistent with other evidence implicating the rhinal region in recognition memory. More importantly, they also provide a dissociation between spatial working memory and object recognition and, hence, show that extensive rhinal lesions are not sufficient to disconnect the hippocampus functionally.

Animals↗

Acquisition and retention of a letter-detection skill.

In two experiments, we examined the acquisition and retention of a letter-detection skill with a consistent-mapping procedure. In Experiment 1, subjects were trained from 0 to 4 sessions at detecting the letter H in displays containing random letters, and retesting occurred after a 1-month delay. Performance improved and in some cases became more automatic, and the performance level was maintained over the retention interval. When tested with a prose passage, the high error rate on the word THE was eliminated after training and after the retention interval, regardless of the amount of training. In Experiment 2, two subjects were given 12 sessions of training followed by a retention test 6 months later. For 1 subject there was also a retention test 15 months after acquisition. Performance improved dramatically with training, and substantial but not complete automaticity was achieved. Performance on the retention tests was close to the final acquisition level. The surprising lack of forgetting in this study was contrasted with the substantial forgetting typically found in studies of verbal learning.

Form Perception↗

Right hemisphere restitution of language and memory functions in right hemisphere language-dominant patients with left temporal lobe epilepsy.

Concomitant with the right hemispheric restitution of language functions after early left hemisphere lesions, suppression effects on originally right hemispheric visuospatial/constructional functions have repeatedly been reported. The present study evaluated this issue in 10 right hemisphere language-dominant patients with temporal lobe epilepsy. Left hemisphere language-dominant patients with left (n = 10) or right (n = 10) temporal lobe epilepsy served as controls. The following results were obtained: in all but one of the right dominant patients, left hemisphere lesions, left hemisphere foci and histories of early left brain damage indicated that secondary language transfer rather than a genetically determination is the more likely cause of the right hemisphere dominance. Despite this transfer, the language functions (comprehension, fluency, reasoning) of the right dominant patients remained significantly impaired. Language generally appeared to be better preserved in patients with an onset of epilepsy before the third year of life or a circumscribed left hemisphere lesion. No suppression effects could be detected on the level of complex cortical language and non-language functions. In contrast, on the level of temporo-limbic memory functions, verbal learning and recognition were left largely intact, albeit mostly at the expense of visuo-spatial learning and memory. The findings of the study thus indicate that the cerebral plasticity of the right hemisphere differs according to the extent of the left-hemisphere lesion, the onset of structural/functional damage and the complexity of the functions requiring restitution. Assuming that language and memory represent neocortical and palaeocortical functions, respectively, the restitution process is seemingly governed by their status in a phylogenetically determined hierarchy of functional importance.

Brain Diseases↗

The mechanisms of spontaneous and provoked confabulations.

Confabulation is a mysterious adjunct of amnesia. It remains unexplained why some patients invent untrue stories in response to questions (provoked confabulations) or even spontaneously with no apparent motivation (spontaneous confabulations). Hypothesized mechanisms range from a desire to fill gaps in memory to a loss of the temporal context in memory. We examined the mechanisms of confabulations in 16 amnesic patients. Patients were classified as spontaneous confabulators if they ever acted according to their confabulations. Provoked confabulations were measured as the number of intrusions in a verbal learning test. We found a double dissociation between the two types of confabulations, indicating that they represent different disorders rather than different degrees of the same disorder. Confabulating patients did not show an increased tendency to fill gaps in memory as measured by the number of fake questions concerning nonexistent items that they answered. Neither type of confabulation correlated with a failure to store new information as gauged with recognition tasks; pure information storage was even found to be normal in some patients. However, we found a positive correlation between several measures of verbal learning and verbal fluency with provoked, but not spontaneous, confabulations. In contrast, spontaneous, but not provoked, confabulations were associated with an inability to recognize the temporal order of stored information as measured by the comparison of two runs of a continuous recognition task. We suggest that provoked confabulations depend on an amnesic subject's search in his deficient memory and are the trade-off for increased item recollection. Spontaneous confabulations appear to be based on a failure to recognize the temporal order of stored information, resulting in erroneous recollection of elements of memory that do not belong together.

Adult↗

Medial temporal lobe atrophy and memory deficits in elderly stroke patients.

Medial temporal lobe atrophy (MTA) and its role in memory deficits have been studied extensively in patients with various dementias and non-degenerative neurologic diseases. In stroke patients MTA is a significant risk factor for dementia. However, its role in memory decline in non-demented stroke patients is not yet known. Our aim was to evaluate the relationship between MTA and cognitive functions in a large cohort of elderly patients, who underwent a comprehensive neuropsychologic examination and magnetic resonance imaging 3 months after an ischemic stroke. The study sample (n = 260) was divided into three groups according to the severity of MTA. After adjusting for age, volume of infarcts and cortical atrophy, we found that patients with moderate to severe MTA performed significantly worse in tests of learning, story recall, visual reproduction, block design and mental speed. In contrast, the groups did not differ in tests of digit span, flexibility, verbal fluency and conceptualization. Our conclusion is that in aged stroke patients, MTA is associated with poor performance in specific cognitive domains. The most vulnerable domains are memory and visuospatial functions, whereas verbal and executive functions seem to be unrelated to MTA.

Aged↗

Acoustic analysis of vocal development in a New World primate, the common marmoset (Callithrix jacchus).

In contrast to humans and songbirds, there is limited evidence of vocal learning in nonhuman primates. While previous studies suggested that primate vocalizations exhibit developmental changes, detailed analyses of the extent and time course of such changes across a species' vocal repertoire remain limited. In a highly vocal primate, the common marmoset (Callithrix jacchus), we studied developmental changes in the acoustic structure of species-specific communication sounds produced in a social setting. We performed detailed acoustic analyses of the spectral and temporal characteristics of marmoset vocalizations during development, comparing differences between genders and twin pairs, as well as with vocalizations from adult marmosets residing in the same colony. Our analyses revealed significant changes in spectral and temporal features as well as variability of particular call types over time. Infant and juvenile vocalizations changed progressively toward the vocalizations produced by adult marmosets. Call types observed early in development that were unique to infants disappeared gradually with age, while vocal exchanges with conspecifics emerged. Our observations clearly indicate that marmoset vocalizations undergo both qualitative and quantitative postnatal changes, establishing the basis for further studies to delineate contributions from maturation of the vocal apparatus and behavioral experience.

Acoustics↗

Perception of native and non-native affricate-fricative contrasts: cross-language tests on adults and infants.

Previous studies have shown improved sensitivity to native-language contrasts and reduced sensitivity to non-native phonetic contrasts when comparing 6-8 and 10-12-month-old infants. This developmental pattern is interpreted as reflecting the onset of language-specific processing around the first birthday. However, generalization of this finding is limited by the fact that studies have yielded inconsistent results and that insufficient numbers of phonetic contrasts have been tested developmentally; this is especially true for native-language phonetic contrasts. Three experiments assessed the effects of language experience on affricate-fricative contrasts in a cross-language study of English and Mandarin adults and infants. Experiment 1 showed that English-speaking adults score lower than Mandarin-speaking adults on Mandarin alveolo-palatal affricate-fricative discrimination. Experiment 2 examined developmental change in the discrimination of this contrast in English- and Mandarin-leaning infants between 6 and 12 months of age. The results demonstrated that native-language performance significantly improved with age while performance on the non-native contrast decreased. Experiment 3 replicated the perceptual improvement for a native contrast: 6-8 and 10-12-month-old English-learning infants showed a performance increase at the older age. The results add to our knowledge of the developmental patterns of native and non-native phonetic perception.

Acoustic Stimulation↗

Knowing where things are in the second year of life: implications for hippocampal development.

Prior data have revealed striking contrasts between 18- and 24-month-old children in place learning, an ability known to depend on the hippocampus (Newcombe, Huttenlocher, Drummey, & Wiley, 1998). The current research examined the development of three other basic abilities of mature spatial competence: the representation of multiple locations, the learning of relations among objects, and the recall of a single location after a substantial filled delay. Results indicated a transition from 18 to 24 months in all three abilities. This evidence supports a general transition in spatial representation that occurs towards the end of infancy. Existing neurobehavioral data suggest that a corresponding change in hippocampal functioning underlies this development.

Age Factors↗

A taxonomy for spatiotemporal connectionist networks revisited: the unsupervised case.

Spatiotemporal connectionist networks (STCNs) comprise an important class of neural models that can deal with patterns distributed in both time and space. In this article, we widen the application domain of the taxonomy for supervised STCNs recently proposed by Kremer (2001) to the unsupervised case. This is possible through a reinterpretation of the state vector as a vector of latent (hidden) variables, as proposed by Meinicke (2000). The goal of this generalized taxonomy is then to provide a nonlinear generative framework for describing unsupervised spatiotemporal networks, making it easier to compare and contrast their representational and operational characteristics. Computational properties, representational issues, and learning are also discussed, and a number of references to the relevant source publications are provided. It is argued that the proposed approach is simple and more powerful than the previous attempts from a descriptive and predictive viewpoint. We also discuss the relation of this taxonomy with automata theory and state-space modeling and suggest directions for further work.

Classification↗

Cognitive optimism: self-deception or memory-based processing heuristics?

In a wide variety of cognitive tasks, people's expectations of what their own performance is, was, and will be are an overestimate of reality. After documenting a number of situations in which people exhibit such overconfidence, several reasons for it are discussed. It is suggested that in these situations, the optimistic bias is not attributable exclusively to self-deception or wishful thinking. Rather, the information yielded up by the cognitive system, in combination with the heuristics used for making judgments of future and past performance tailored to the specific questions asked of participants, produces a bias toward believing that one knows, knew, and will perform better than actual performance substantiates. Consequently, in the cognitive domain, the inflated beliefs that result in overconfidence also result in cessation of efforts before the correct solution of problems is ascertained, before accurate retrieval of memorial information is attained, or before adequate learning of new material has been accomplished. This effect seems in contrast to findings on people's moods and self-esteem in real-world or threatening situations that suggest that an optimistic bias in these domains be person protective and adaptive.

Journal Article↗