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PubMed2002

Place and matching-to-place spatial learning affected by rat inbreeding (Dark-Agouti, Fischer 344) and albinism (Wistar, Sprague-Dawley) but not domestication (wild rat vs. Long-Evans, Fischer-Norway).

Domestication has been shown to produce a shift in both morphological and behavioral characteristics of animals. While changes in body weight, brain size, reproductive rates, and temperament are well documented, the effects of domestication on learning and memory are not as clearly understood. This issue is of particular importance to the use of rodent models in learning and memory where the domestication of Rattus norvegicus for research has resulted in the availability of numerous strains. To investigate cognitive effects resulting frm domestication, we examined the spatial performance of a number of rat strains: wild, Long-Evans, Fischer-Norway, Dark-Agouti, Wistar, Fischer 344, Sprague-Dawley. The wild rats served as a baseline for comparing inbred and outbred domestic strains and pigmented and albino domestic strains. Place (a measure of nonspatial and procedural learning), matching-to-place (spatial working memory), and probe (retention) performance were measured in the Morris swimming pool task. The task is an ideal means for comparing different rat strains because place learning has not been selected for in the domestication of Rattus norvegicus and because the task is ethologically relevant. The results indicated that wild rats and Long-Evans rats did not differ on any measure, with Fischer-Norway rats being only slightly inferior. Larger impairments were found in Wistar > Fischer 344 > Dark-Agouti > Sprague-Dawley strains. Impairments were more obvious on place acquisition but also occurred in matching-to-place performance. Platform crosses, but not quadrant preference was found to be correlated with place learning. In general, although nonspatial and spatial deficits were associated with both inbreeding and albinism, impaired spatial performance is not a necessary result of domestication.

Animals↗

PubMed1990

Music during learning of a tactual-spatial task affects later response generalization.

Equal numbers of men and women learned a finger maze, with half of the subjects initially using their right hands and the other half using their left hands. To reach criterion, subjects receiving music in the ear ipsilateral to the hand used required more trials than did those receiving no music. Furthermore, when the right hand ran the maze, music played to the ipsilateral ear also delayed learning, compared with music played contralaterally. Binaural music delayed learning when the left hand was used but not when the right hand was used. Possible causes of these effects are suggested. When subjects switched hands and relearned the maze, the number of trials to criterion depended on the group subjects were in during initial learning and not on the group they were in during the hand reversal (response generalization) trials. Although the music condition used determined the effect of music on initial learning and on response generalization, some evidence is presented that indicates that the two effects are not entirely interdependent and that they may even involve different mechanisms.

Adult↗

PubMed2007

Impaired spatial learning in the APPSwe + PSEN1DeltaE9 bigenic mouse model of Alzheimer's disease.

Mice co-expressing the Swedish amyloid precursor protein mutation (APP(Swe)) and exon 9 deletion (DeltaE9) of the PSEN1 gene begin to develop amyloid plaques at 6-7 months of age. We demonstrate here a spatial learning deficit in 7-month-old APP(Swe) + PSEN1DeltaE9 bigenic mice using an adaptation of the Barnes maze. Mice were first trained on a cued target followed by a hidden-target condition. Although bigenic mice quickly learned the cued-target version of the task, they were significantly impaired when switched to the hidden-target version. In contrast, a separate group of double-transgenic mice trained first on the spatial hidden-target version of the task were unimpaired relative to wild-type controls. We propose that processes such as general rule learning, context learning and exploratory habituation exert a greater influence when the testing environment is novel and overshadow the spatial memory deficit in naive bigenic mice. However, when cued-target training is conducted first, these processes habituate and the spatial learning deficit is unmasked. Seven-month-old APP(Swe) + PSEN1DeltaE9 mice were unimpaired on tests of memory that did not involve learning the rules governing spatial associations.

Alzheimer Disease↗

PubMed2002

Patient-focused urban tele-ophthalmology services.

Since 2000, routine tele-ophthalmology services have been provided by St Erik's Eye Hospital to three large urban primary care centres in Stockholm. Diagnostic support from the specialist eye hospital to primary care centres uses video slit-lamps and realtime videoconferencing. After the initial introduction period at the primary care centres, the number of teleconsultations stabilized at a very low level. Despite this, the general practitioners learned to handle more diagnostic conditions by themselves and to identify what diagnostic situations should be referred to a specialist without having to consult the specialist beforehand via telemedicine. The availability of instant eye expertise via telemedicine therefore proved to be an excellent on-the-job training tool to develop and maintain the diagnostic competence of general practitioners. Patient satisfaction was high.

Eye Diseases↗

PubMed2002

Failure to find evidence of stimulus generalization within pictorial categories in pigeons.

Pigeons' key pecks were reinforced in the presence of pictures from one of two categories, cats or cars. A single picture associated with reinforcement was used in Experiment 1, and 20 pictures from the same category were associated with reinforcement in Experiment 2. Pigeons then were presented with novel test pictures from the training category and from the other, previously unseen, category. During Session 1 of testing, pigeons pecked no more often at pictures from the reinforced category than at pictures from the previously unseen category. When pigeons were trained with pictures associated with reinforcement or its absence from different categories in Experiment 3, differential responding to novel pictures from different categories appeared during Session 1. These findings argue against a process of automatic stimulus generalization within natural categories and in favor of the position that category distinctions are not made until members of at least two categories are compared with one another.

Animals↗

PubMed2005

Statistical computations over a speech stream in a rodent.

Statistical learning is one of the key mechanisms available to human infants and adults when they face the problems of segmenting a speech stream (Saffran, Aslin, & Newport, 1996) and extracting long-distance regularities (G6mez, 2002; Peña, Bonatti, Nespor, & Mehler, 2002). In the present study, we explore statistical learning abilities in rats in the context of speech segmentation experiments. In a series of five experiments, we address whether rats can compute the necessary statistics to be able to segment synthesized speech streams and detect regularities associated with grammatical structures. Our results demonstrate that rats can segment the streams using the frequency of co-occurrence (not transitional probabilities, as human infants do) among items, showing that some basic statistical learning mechanism generalizes over nonprimate species. Nevertheless, rats did not differentiate among test items when the stream was organized over more complex regularities that involved nonadjacent elements and abstract grammar-like rules.

Animals↗

PubMed2001

Combining qualitative and quantitative methods in assessing hospital learning environments.

Clinical education is a vital component in the curricula of pre-registration nursing courses and provides student nurses with the opportunity to combine cognitive, psychomotor, and affective skills. Clinical practice enables the student to develop competencies in the application of knowledge, skills, and attitudes to clinical field situations. It is, therefore, vital that the valuable clinical time be utilised effectively and productively. Nursing students' perception of the hospital learning environment were assessed by combining quantitative and qualitative approaches. The Clinical Learning Environment Inventory, based on the theoretical framework of learning environment studies, was developed and validated. The quantitative and qualitative findings reinforced each other. It was found that there were significant differences in students' perceptions of the actual clinical learning environment and their preferred learning environment. Generally, students preferred a more positive and favourable clinical environment than they perceived as being actually present.

Attitude of Health Personnel↗

PubMed2002

The generality of selective observing.

Four rats obtained food pellets by poking a key and 5-s presentations of the discriminative stimuli by pressing a lever. Every 1 or 2 min, the prevailing schedule of reinforcement for key poking alternated between rich (either variable-interval [VI] 30 s or VI 60 s) and lean (either VI 240 s, VI 480 s, or extinction) components. While the key was dark (mixed-schedule stimulus), no exteroceptive stimulus indicated the prevailing schedule. A lever press (i.e., an observing response), however, illuminated the key for 5 s with either a steady light (S+), signaling the rich reinforcement schedule, or a blinking light (S-), signaling the lean reinforcement schedule. One goal was to determine whether rats would engage in selective observing (i.e., a pattern of responding that maintains contact with S+ and decreases contact with S-). Such a pattern was found, in that a 5-s presentation of S+ was followed relatively quickly by another observing response (which likely produced another 5-s period of S+), whereas exposure to S- resulted in extended breaks from observing. Additional conditions demonstrated that the rate of observing remained high when lever presses were effective only when the rich reinforcement schedule was in effect (S+ only condition), but decreased to a low level when lever presses were effective only during the lean reinforcement component (S- only condition) or when lever presses had no effect (in removing the mixed stimulus or presenting the multiple-schedule stimuli). These findings are consistent with relativistic conceptualizations of conditioned reinforcement and extend the generality of selective observing to procedures in which the experimenter controls the duration of stimulus presentations, the schedule components both offer intermittent food reinforcement, and rats serve as subjects.

Animals↗

PubMed1986

Rolipram forms a potent discriminative stimulus in drug discrimination experiments in rats.

Long Evans rats were trained to discriminate 0.2 mg/kg IP (+/-)-rolipram from vehicle injection in a food-motivated two-lever operant task. Eight out of nine rats acquired the discrimination after an average of 91 sessions (min 65, max 137). The ED50 of (+/-)-rolipram was 0.06 mg/kg IP. Generalization tests with (-)- and (+)-rolipram showed that the (-)-isomer was 8 times more active than (+)-rolipram with an ED50 of 0.06 and 0.4 mg/kg IP respectively. The phosphodiesterase inhibitor RO 20-1724 partially (83%) generalized to (+/-)-rolipram in doses of 0.6 and 1.0 mg/kg IP. IBMX 5 mg/kg IP showed 63% generalization. Tests with imipramine and the (+)- and (-)-isomer of the noradrenaline uptake inhibitor oxaprotiline suggest that NA-uptake inhibiting drugs do not form an interoceptive cue which is (+/-)-rolipram-like. dbcAMP 12.5 mg/kg SC and 100 mg/kg SC dbcGMP did not generalize to the training drug. The nature of the discriminative stimulus produced by this dose of (+/-)-rolipram in rats remains to be elucidated.

Animals↗

PubMed1984

Generality in the verbal tacting of autistic children as a function of "naturalness" in antecedent control.

Two autistic children were taught to emit verbal tacts under two conditions--one employing verbal antecedent stimuli in the training process and the other employing so-called naturalistic antecedent stimuli. Although acquisition was more rapid when verbal antecedents were used, the generality of learning was substantially better for language taught under naturalistic stimulus control. Implications of these findings for the instruction of autistic children are considered in the context of current information on stimulus control.

Autistic Disorder↗

PubMed1980

General practitioners, students and the objectives of general practice attachments.

The objectives for undergraduate experience in general practice vary little from school to school although the timing and duration of attachment does. Students' views of the relevance and achievement of these objectives to a two-week attachment in the final year of St. George's Hospital Medical Schools' old curriculum are shown to differ from those of their GPs. The implications of these differences for planning undergraduate learning in general practice are discussed.

Curriculum↗

PubMed2006

Towards a "virtual pigeon": a new technique for investigating avian social perception.

The purpose of the present study is to examine the applicability of a computer-generated, virtual animal to study animal cognition. Pigeons were trained to discriminate between movies of a real pigeon and a rat. Then, they were tested with movies of the computer-generated (CG) pigeon. Subjects showed generalization to the CG pigeon, however, they also responded to modified versions in which the CG pigeon was showing impossible movement, namely hopping and walking without its head bobbing. Hence, the pigeons did not attend to these particular details of the display. When they were trained to discriminate between the normal and the modified version of the CG pigeon, they were able to learn the discrimination. The results of an additional partial occlusion test suggest that the subjects used head movement as a cue for the usual vs. unusual CG pigeon discrimination.

Animals↗

PubMed1987

Experimental analysis of syntax training in Broca's aphasia: a generalization and social validation study.

A multiple baseline design across responses was used to examine the effect of syntax training on the sentence production of 4 individuals with chronic Broca's aphasia. Subjects were trained to produce five exemplars of five sentence types from Helm's Elicited Language Program for Syntax Stimulation (Helm-Estabrooks, 1981). Generalization and maintenance of trained sentence types to novel exemplars and novel stimulus conditions served as dependent measures. In addition, five naïve judges rated subjects' responses before and following the treatment in terms of their "adequacy." Generalization to novel exemplars was demonstrated sequentially by 3 subjects (i.e., following the teaching of all five forms), and the remaining subject demonstrated generalization for three of five sentence types trained. Maintenance was variable across subjects and sentence types. Generalization across stimulus conditions was limited for all subjects. Adequacy judgments revealed improved communication skills for wh-questions but limited changes in the perceived adequacy of subjects' declarative responses. These findings indicate that the effects of syntax training procedures are limited to those grammatical constructions taught, that generalization of learned forms to novel stimulus conditions is not an automatic consequence of acquisition, and that the effect of such training on the adequacy of subjects' responses may be limited.

Adult↗

PubMed1968

Discriminative control of "attention".

Three pigeons were trained to discriminate between two tones differing in frequency in the presence of light of one color (A), and not to discriminate between the tones in the presence of light of another color (B). Generalization functions that were determined in the presence of light A showed control of behavior by the frequency of the tone; those determined in the presence of light B did not.

Animals↗

PubMed2006

Addressing the needs and priorities of medical teachers through a collaborative intensive faculty development programme.

Faculty development in medical education is crucial for developing and sustaining quality education in medical schools. However, examples of successful intensive programmes based on experiential and collaborative learning are generally lacking in the literature. The Medical Education Unit of National University of Singapore conducted a three-day intensive programme on core competences in medical education. This paper highlights the process of programme development, programme structure, challenges faced and strategies adopted. It also describes the approach taken to educational programme evaluation along with the results. The programme structure was based on experiential and collaborative learning models. Participants contributed to all activities and emerged as facilitators and learners to gain first-hand experience of the complex educational processes. Each individual session was sequential with a brief plenary, demonstration, practicum and reflection. Pre-programme needs assessment showed that even the experienced teachers perceived a need to further improve their educational competencies.

Cooperative Behavior↗

PubMed1985

Drug discrimination procedures: roles of relative stimulus control in two-drug cases.

Two groups of five pigeons each were trained to discriminate morphine 5.6 mg/kg vs cocaine 5.6 mg/kg (High dose cocaine group), and morphine 5.6 mg/kg vs cocaine 3.0 mg/kg (Low dose cocaine group), respectively. Within both groups, cocaine dose generalization gradients were radically flatter in comparison to those obtained when the same cocaine dosages were discriminated from saline, whereas morphine gradients, analogously compared, were only moderately so. Responding to non-drug tests did not deviate significantly from random in either group. After lowering morphine training doses to 3.0 mg/kg in a systematic replication of the experiment, training drugs generalization gradients took symmetrical, flattened, shapes in the High dose cocaine group, whereas in the Low dose cocaine group the previous relation between gradients was enhanced. Responding to non-drug tests in this phase did not deviate significantly from random in the High dose cocaine group, whereas the reverse was true with the Low dose cocaine group. Tests with novel drugs (apomorphine, LSD, pentobarbital and delta 9-THC), did not differentiate between the groups. The roles of generalization gradients, non-drug tests and novel drugs tests as measures of relative stimulus control of training stimuli in drug discrimination experiments are discussed within the framework of a drug discrimination model.

Animals↗

PubMed2000

Automating parallel implementation of neural learning algorithms.

Neural learning algorithms generally involve a number of identical processing units, which are fully or partially connected, and involve an update function, such as a ramp, a sigmoid or a Gaussian function for instance. Some variations also exist, where units can be heterogeneous, or where an alternative update technique is employed, such as a pulse stream generator. Associated with connections are numerical values that must be adjusted using a learning rule, and and dictated by parameters that are learning rule specific, such as momentum, a learning rate, a temperature, amongst others. Usually, neural learning algorithms involve local updates, and a global interaction between units is often discouraged, except in instances where units are fully connected, or involve synchronous updates. In all of these instances, concurrency within a neural algorithm cannot be fully exploited without a suitable implementation strategy. A design scheme is described for translating a neural learning algorithm from inception to implementation on a parallel machine using PVM or MPI libraries, or onto programmable logic such as FPGAs. A designer must first describe the algorithm using a specialised Neural Language, from which a Petri net (PN) model is constructed automatically for verification, and building a performance model. The PN model can be used to study issues such as synchronisation points, resource sharing and concurrency within a learning rule. Specialised constructs are provided to enable a designer to express various aspects of a learning rule, such as the number and connectivity of neural nodes, the interconnection strategies, and information flows required by the learning algorithm. A scheduling and mapping strategy is then used to translate this PN model onto a multiprocessor template. We demonstrate our technique using a Kohonen and backpropagation learning rules, implemented on a loosely coupled workstation cluster, and a dedicated parallel machine, with PVM libraries.

Algorithms↗

PubMed1996

Parallel processing of chemical information in a local area network--II. A parallel cross-validation procedure for artificial neural networks.

This paper describes a parallel cross-validation (PCV) procedure, for testing the predictive ability of multi-layer feed-forward (MLF) neural networks models, trained by the generalized delta learning rule. The PCV program has been parallelized to operate in a local area computer network. Development and execution of the parallel application was aided by the HYDRA programming environment, which is extensively described in Part I of this paper. A brief theoretical introduction on MLF networks is given and the problems, associated with the validation of predictive abilities, will be discussed. Furthermore, this paper comprises a general outline of the PCV program. Finally, the parallel PCV application is used to validate the predictive ability of an MLF network modeling a chemical non-linear function approximation problem which is described extensively in the literature.

Artificial Intelligence↗