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Discriminative stimulus properties of toluene in the rat.

Rats were trained to discriminate toluene (100 mg/kg, IP) from vehicle in a two-lever operant task. Acquisition of the discrimination required a range of 85-219 training days. Injections of either methohexital (0.5-10 mg/kg) or oxazepam (0.5-20 mg/kg) produced toluene-lever responding in a dose-dependent fashion in most animals. The discriminative stimulus properties of toluene were not found to generalize to chlorpromazine (0.3-10 mg/kg). These results are consistent with those obtained in the mouse and provide further evidence that toluene has stimulus properties similar to those of CNS depressant drugs. These results further suggest that toluene may have drug abuse potential of the CNS depressant type.

Animals↗
PubMed1977

Teaching patients with peripheral vascular disease.

The teaching of a patient with peripheral vascular disease offers many challenges to the nurse. Although content should be understood and utilized by the patient and significant others, of primary importance is the belief that the learner is the curriculum and that his perception of self and his problems is the focus of teaching. The learning needs generally should be considered as the needs of an adult individual, who has many past experiences and an interest in the present and future. This patient may experience pain from his disease and may require the assistance and support of others. If the purpose of treatment is to improve circulation and prevent trauma and infection, then patient instruction must be recognized as a vital tool in therapy. But the nurse cognizant of the progressiveness of peripheral vascular disease must capitalized on the teachable moments--when the patient is ready and the learning is needed.

Adult↗
PubMed2006

Categorization of visual stimuli in the honeybee Apis mellifera.

Categorization refers to the classification of perceptual input into defined functional groups. We present and discuss evidence suggesting that stimulus categorization can also be found in an invertebrate, the honeybee Apis mellifera, thus underlining the generality across species of this cognitive process. Honeybees show positive transfer of appropriate responding from a trained to a novel set of visual stimuli. Such a transfer was demonstrated for specific isolated features such as symmetry or orientation, but also for assemblies (layouts) of features. Although transfer from training to novel stimuli can be achieved by stimulus generalization of the training stimuli, most of these transfer tests involved clearly distinguishable stimuli for which generalization would be reduced. Though in most cases specific experimental controls such as stimulus balance and discriminability are still required, it seems appropriate to characterize the performance of honeybees as reflecting categorization. Further experiments should address the issue of which categorization theory accounts better for the visual performances of honeybees.

Animals↗
PubMed2003

Language learning and innateness: some implications of Compounds Research.

In noun compounds in English, the modifying noun may be singular (mouse-eater) or an irregularly inflected plural (mice-eater), but regularly inflected plurals are dispreferred (*rats-eater). This phenomenon has been taken as strong evidence for dual-mechanism theories of lexical representations, which hold that regular (rule-governed) and irregular (exception) items are generated by qualitatively different and innately specified mechanisms. Using corpus analyses, behavioral studies, and computational modeling, we show that the rule-versus-exceptions approach makes a number of incorrect predictions. We propose a new account in which the acceptability of modifiers is determined by a constraint satisfaction process modulated by semantic, phonological, and other factors. The constraints are acquired by the child via general purpose learning algorithms, based on noun compounds and other constructions in the input. The account obviates the regular/irregular dichotomy while simultaneously providing a superior account of the data.

Child↗
PubMed2005

Modeling individual differences in cognition.

Many evaluations of cognitive models rely on data that have been averaged or aggregated across all experimental subjects, and so fail to consider the possibility of important individual differences between subjects. Other evaluations are done at the single-subject level, and so fail to benefit from the reduction of noise that data averaging or aggregation potentially provides. To overcome these weaknesses, we have developed a general approach to modeling individual differences using families of cognitive models in which different groups of subjects are identified as having different psychological behavior. Separate models with separate parameterizations are applied to each group of subjects, and Bayesian model selection is used to determine the appropriate number of groups. We evaluate this individual differences approach in a simulation study and show that it is superior in terms of the key modeling goals of prediction and understanding. We also provide two practical demonstrations of the approach, one using the ALCOVE model of category learning with data from four previously analyzed category learning experiments, the other using multidimensional scaling representational models with previously analyzed similarity data for colors. In both demonstrations, meaningful individual differences are found and the psychological models are able to account for this variation through interpretable differences in parameterization. The results highlight the potential of extending cognitive models to consider individual differences.

Cognition↗
PubMed2004

Nursing students' perceptions of hospital learning environments--an Australian perspective.

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. Various studies have suggested that not all practice settings are able to provide nursing students with a positive learning environment. In order to maximize nursing students' clinical learning outcomes, there is a need to examine the clinical learning environment. The purpose of this study was to assess pre-registration nursing students' perceptions of hospital learning environments during clinical field placement. Quantitative and qualitative methodology was used. One hundred and eight students provided quantitative data through completion of the survey instrument, the Clinical Learning Environment Inventory (Actual and Preferred forms). Each form is a 5-point Likert-type questionnaire, made up of 35 items consisted of 5 scales with 7 items per scale. Qualitative data, obtained through semi-structured interview of 21 students from the same cohort, were used to explain and support the quantitative findings. There were significant differences between students' actual and preferred perceptions of the clinical learning environments. Generally students preferred a more positive and favourable clinical environment than they perceived as being actually present. Since participants consisted of nursing students from just one university nursing school in South Australia, the findings may not be representative of all nursing students in general with respect to their clinical placement. However, the value of this study lies in the resulting implication for nursing education and future research. A better understanding of what constitutes quality clinical education from the students' perspective would be valuable in providing better educational experiences.

Clinical Competence↗
PubMed1975

A general practitioner's study of his own workload and patient morbidity.

In 1972 a study of workload and morbidity was undertaken by a New South Wales general practitioner. The writer analysed 5,618 of his own face-to-face patient contacts and have been set out below. A comparison was also made between the writer's morbidity statistics and those of the Australian Morbidity Survey. Both surveys were conducted at the same time and it was interesting to note a marked similarity in the percentages of disease episodes when classified into broad groups (such as respiratory disease, for example). The results have been useful as a basis for future research, as an educational tool for undergraduates and graduates learning about general practice and as an aid in practice management planning.

Adolescent↗
PubMed1993

[Myoclonic hyperkinesis induced by repeated administration of picrotoxin into rat neostriatum].

The effects of three-week daily intrastriatal 45 mcg GABA, 5 and 15 mcg picrotoxin and 5 bicuculline microinjections in rats were investigated. The inhibition of avoidance conditioning in shuttle box was registered in first days of GABA microinjection; stereotyped behaviour and paradoxal freezing in further GABA effects were developed. After the short orofacial dyskinesia as the acute picrotoxin effects, the choreo-myoclonic limb jerks, with the distinct generalization stage were observed. Picrotoxin dose increasing in toxic convulsive status results. No any dystonia, but strong avoidance conditioning inhibition in all three weeks of bicuculline treatment were observed only. The novel functional and controlled model of choreo-myoclonic hyperkinesis is proposed. The role of the striatal GABA system in human neuro-motor dyskinesias were discussed.

Animals↗
PubMed2005

Strategy development and learning to spell new words: generalization of a process.

The authors used microgenetic methods in 2 experiments to examine children's and adults' progress from initial attempts at spelling nonwords to later direct memory retrieval of the spellings. Participants repeatedly spelled nonwords presented in computerized, dictated-word spelling tests over several weeks. Following each spelling, participants provided retrospective strategy reports. Half of the children showed a gradual shift from spelling words with effortful backup strategies to fast retrieval; half of the children continued using backup strategies that were fast and effective for them. Relatively more adults shifted from backup strategies to retrieval, but otherwise their patterns of spelling development were quite similar to those of the children. This research provides support for the generalizability of the overlapping waves model to nonalgorithmic domains. It also demonstrates parallels between children and adults in learning to spell new words.

Adult↗
PubMed2004

The functions of the orbitofrontal cortex.

The orbitofrontal cortex contains the secondary taste cortex, in which the reward value of taste is represented. It also contains the secondary and tertiary olfactory cortical areas, in which information about the identity and also about the reward value of odours is represented. The orbitofrontal cortex also receives information about the sight of objects from the temporal lobe cortical visual areas, and neurons in it learn and reverse the visual stimulus to which they respond when the association of the visual stimulus with a primary reinforcing stimulus (such as taste) is reversed. This is an example of stimulus-reinforcement association learning, and is a type of stimulus-stimulus association learning. More generally, the stimulus might be a visual or olfactory stimulus, and the primary (unlearned) positive or negative reinforcer a taste or touch. A somatosensory input is revealed by neurons that respond to the texture of food in the mouth, including a population that responds to the mouth feel of fat. In complementary neuroimaging studies in humans, it is being found that areas of the orbitofrontal cortex are activated by pleasant touch, by painful touch, by taste, by smell, and by more abstract reinforcers such as winning or losing money. Damage to the orbitofrontal cortex can impair the learning and reversal of stimulus-reinforcement associations, and thus the correction of behavioural responses when there are no longer appropriate because previous reinforcement contingencies change. The information which reaches the orbitofrontal cortex for these functions includes information about faces, and damage to the orbitofrontal cortex can impair face (and voice) expression identification. This evidence thus shows that the orbitofrontal cortex is involved in decoding and representing some primary reinforcers such as taste and touch; in learning and reversing associations of visual and other stimuli to these primary reinforcers; and in controlling and correcting reward-related and punishment-related behavior, and thus in emotion. The approach described here is aimed at providing a fundamental understanding of how the orbitofrontal cortex actually functions, and thus in how it is involved in motivational behavior such as feeding and drinking, in emotional behavior, and in social behavior.

Animals↗
PubMed1986

Discriminative stimulus properties of phenylisopropylamine derivatives.

The phenylisopropylamine unit is a common structural fragment amongst many centrally-acting agents. However, these agents do not necessarily produce similar behavioral effects in test subjects. For example, the phenylisopropylamine derivative amphetamine is a central nervous system (CNS) stimulant whereas its 2,5-dimethoxy-4-methyl analog, i.e. DOM, is considered to be a hallucinogen. Employing animals trained to discriminate either (+)-amphetamine or (+/-)-DOM from saline in a two-lever operant procedure, stimulus generalization studies were conducted to evaluate members of a series of methoxy-substituted, and related, phenylisopropylamines. In this manner, it was possible to classify these agents as to which produced amphetamine-like effects, and which produced DOM-like effects.

DOM 2,5-Dimethoxy-4-Methylamphetamine↗
PubMed1996

Optimal nonlinear training in the multi-class proximity problem.

Using a signal-to-noise analysis, the effects of nonlinear modulation of the Hebbian learning rule in the multi-class proximity problem are investigated. Both random classification and classification provided by a Gaussian and a binary teacher are treated. Analytic expressions are derived for the learning and generalization rates around an old and a new prototype. For the proximity problem with binary inputs but Q'-state outputs, it is shown that the optimal modulation is a combination of a hyperbolic tangent and a linear function. As an illustration, numerical results are presented for the two-class and the Q' = 3 multi-class problem.

Learning↗
PubMed1994

The learning ability paradox in adult metamemory research: where are the metamemory differences between good and poor learners?

College students' ability to judge whether a studied item had been learned well enough to be recalled on a later test was examined in three experiments with self-paced learning procedures. Generally, these learners compensated for item difficulty when allocating study time, studying hard items longer than easy items, but they still recalled more easy items than hard items and tended to drop items out too soon. When provided with test opportunities during study or a delay between study and judgment, learners compensated significantly more for item difficulty and recalled substantially more. Paradoxically, good and poor learners compensated similarly for item difficulty and benefited similarly from testing during study and from delayed decision making. Thus, although the ability to make metamemory decisions was shown to be important for effective learning, these decisions were made equally well by good and poor associative learners. An analysis of tasks used to investigate metamemory-memory relationships in adult learning may provide an account for this apparent learning ability paradox.

Humans↗
PubMed2025

SetBERT: the deep learning platform for contextualized embeddings and explainable predictions from high-throughput sequencing.

MOTIVATION: High-throughput sequencing (HTS) is a modern sequencing technology used to profile microbiomes by sequencing thousands of short genomic fragments from the microorganisms within a given sample. This technology presents a unique opportunity for artificial intelligence to comprehend the underlying functional relationships of microbial communities. However, due to the unstructured nature of HTS data, nearly all computational models are limited to processing DNA sequences individually. This limitation causes them to miss out on key interactions between microorganisms, significantly hindering our understanding of how these interactions influence the microbial communities as a whole. Furthermore, most computational methods rely on post-processing of samples which could inadvertently introduce unintentional protocol-specific bias. RESULTS: Addressing these concerns, we present SetBERT, a robust pre-training methodology for creating generalized deep learning models for processing HTS data to produce contextualized embeddings and be fine-tuned for downstream tasks with explainable predictions. By leveraging sequence interactions, we show that SetBERT significantly outperforms other models in taxonomic classification with genus-level classification accuracy of 95%. Furthermore, we demonstrate that SetBERT is able to accurately explain its predictions autonomously by confirming the biological-relevance of taxa identified by the model. AVAILABILITY AND IMPLEMENTATION: All source code is available at https://github.com/DLii-Research/setbert. SetBERT may be used through the q2-deepdna QIIME 2 plugin whose source code is available at https://github.com/DLii-Research/q2-deepdna.

Deep Learning↗
PubMed1994

Occasion-setting training renders stimuli more similar: acquired equivalence between the targets of feature-positive discriminations.

In two experiments rats received training on two concurrent appetitive feature-positive discriminations. A preliminary test in Experiment 1 confirmed previous demonstrations of the transfer of occasion-setting properties--the feature from one of these discriminations was better able to facilitate responding to the occasion-set target CS from the second discrimination than to a control stimulus that had not been the subject of occasion-setting. The source of this transfer was investigated in a second phase of training, and in Experiment 2. In both experiments one of the occasion-set CSs was paired with food, and generalization of appetitive conditioned responding from this stimulus to the second occasion-set CS, and to a control cue, was examined. There was more generalization from the first occasion-set CS to the second CS that had also been occasion-set than to the control cue. This is taken as evidence that occasion-set CSs are rendered more similar as a result of their common training history. The implications of these findings for explaining transfer of occasion setting are discussed.

Animals↗
PubMed2006

Some tests of response membership in acquired equivalence classes.

Pigeons were trained on many-to-one matching in which pairs of samples, each consisting of a visual stimulus and a distinctive pattern of center-key responding, occasioned the same reinforced comparison choice. Acquired equivalence between the visual and response samples then was evaluated by reinforcing new comparison choices to one set of samples, and examining generalization of these choices to the other samples. Three separate experiments found no evidence of such generalization, as indexed by performance on class-consistent versus class-inconsistent tests. Other tests showed that the pigeons' center-key response patterns during training had indeed served as a conditional cue for choice. These results do not support the hypothesis that different defined responses can become members of acquired equivalence classes.

Animals↗
PubMed1984

Stimulus properties of clonidine in chronically morphine treated rats trained to a morphine-saline discrimination.

In an operant behavior procedure of lever pressing on an FR 10 schedule of food reinforcement, morphine dependent and nondependent rats were trained to respond on a lever on one side of the food tray after a morphine (10 mg/kg i.p.) injection and to respond on a lever on the alternate side after a saline injection. Following discrimination training, in both dependent and nondependent rats saline was generalized to various doses of clonidine (10, 30 and 50 micrograms/kg i.p.). A response inhibition of about 65% was obtained with the highest dose. It was concluded that, even if clonidine can suppress signs of narcotic withdrawal, the internal state induced by morphine in an abstinent rat does differ from the one induced by clonidine in the same animal.

Animals↗