Discrimination learning and stimulus generalization by impulsive and reflective children.
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Achievement↗
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Generalization patterns associated with training least phonological knowledge.
This study examined the relationship between productive phonological knowledge and generalization learning patterns in phonologically disordered children. Nine functionally misarticulating children (ages 3:8-5:9) were trained on aspects of their phonological systems that were characterized as inventory constraints that constituted "least phonological knowledge" in relation to the adult sound system (Elbert & Gierut, 1986). The misarticulated sounds were trained in the context of consonant clusters. Although all the subjects exhibited equivalent levels of phonological knowledge on the same misarticulated sounds and identical training was provided, three different learning patterns were observed. Results are discussed with regard to the characterization of phonological knowledge in underlying representations that are depicted as "non-adult-like" or incorrect relative to the target sound system. Implications for clinical assessment are discussed.
Articulation Disorders↗
Rats with congenital learned helplessness respond less to sucrose but show no deficits in activity or learning.
Inbred rat strains for congenital learned helplessness (cLH) and for congenital resistance to learned helplessness (cNLH) were investigated as a model to study genetic predisposition to major depression. Congenitally helpless rats respond less to sucrose under a progressive ratio schedule. This is not confounded by locomotor hypoactivity: in contrast, cLH rats show a slight hyperactivity during the first 5 min of an open field test. cLH rats acquire operant responding to sucrose as readily as cNLH rats and exhibit normal memory acquisition and retrieval in the Morris water maze, thus ruling out general learning deficits as the cause of the decreased response to sucrose. Reduced total responses and reduced breaking points for sucrose in the cLH strain argue for anhedonia, which is an analogue to loss of pleasure essential for the diagnosis of major depressive episodes, and thus confirm the validity of congenitally learned helpless rats as a model of major depression.
Animals↗
The treatment of anomia using errorless learning.
In the contemporary literature, errorless learning is thought to have benefits over more traditional trial-and-error methods. The most prominent investigations of errorless learning are those designed for rehabilitation of severe memory impairments, including numerous demonstrations of effective amelioration of word-finding difficulties (Baddeley & Wilson, 1994; Clare, Wilson, Breen, & Hodges, 1999; Clare et al., 2000; Evans et al., 2000). Despite this, there are very few reports on the application of purely errorless learning to people with aphasia (Fillingham, Hodgson, Sage, & Lambon Ralph, 2003). The aim of this study was to compare directly the efficacy of errorless and errorful learning in a case series of 11 aphasic people with pronounced word-finding difficulties. Previous studies of errorless learning and, more recently, studies of rehabilitation have suggested that cognition is an important factor for determining outcome (Helm-Estabrooks, 2002; Robertson & Murre, 1999). Therefore, a thorough language and neuropsychological assessment battery was completed with each participant. Naming therapy was carried out to contrast errorless and errorful therapy in a case series analysis. Errorless learning proved to be as effective as the more traditional, errorful approach in the majority of cases in terms of both immediate improvement and at follow up assessment. Without exception, the patients preferred the errorless learning therapy. Strikingly, it was found that language skill did not predict therapy outcome. Participants who responded better overall, had better recognition memory, executive/problem solving skills and monitoring ability. This replicates recent findings that frontal executive skills are crucial for rehabilitation (Robertson & Murre, 1999). Also, participants who did better at errorful treatment were those with the best working and recall memory, and attention. It is probable that these factors are essential cognitive components for providing effective monitoring and feedback systems to a more general learning mechanism.
Adult↗
Computer-assisted learning (CAL) for general and specialist nursing education.
Computer-assisted learning (CAL) may be defined as any learning that is mediated by a computer and which requires no direct interaction between the user and a human instructor in order to run. Instead, CAL presents the user with an interface (constructed by an educator skilled in the field of study) which allows the user to follow a lesson plan or may allow self-directed access to particular information of interest. CAL has been claimed to improve knowledge retention and achievement scores, enhance clinical judgement skills and reduce required instruction time; performing as well (if not better) when compared to other more traditional education techniques. The advantages of the utilisation of CAL in nursing education can be made clear by consideration of adult education theory and curriculum design, as well as the particular learning needs of nurses themselves. Research and development into a theoretical framework for CAL design and implementation has allowed the identification of beneficial aspects of CAL resources. Although the cost of commercial software may be prohibitive to some institutions, possibilities exist for educators to create their own CAL packages relatively simply.
Adult↗
The evaluation of three computer-assisted learning packages for general dental practitioners.
Two studies were undertaken to determine the acceptability of computer-assisted learning (CAL) to general dental practitioners. The first was a single programme in two parts designed to give experience in orthodontic cases assessment and treatment planning, developed at the Bristol Dental School. The second contained two modules, one on the planning and management of dental biopsy and the other on surgical endodontics, developed within the Leeds Dental Institute. An identical self-administered questionnaire was completed by participants in the evaluation study. Knowledge and skill gains were indicated following study of the modules. The modules were also found to be easy to use and useful. The CAL approach was rated positively compared to audio tapes, books and journals, but a less consistent pictures when CAL was compared with videotapes. The study provides evidence for the acceptability and potential of the CAL approach to general dental practitioners.
Attitude to Computers↗
A comparison of neurocognitive function in nonsmoking and chronically smoking short-term abstinent alcoholics.
Approximately 70-90% of individuals in North America seeking treatment for alcoholism are chronic smokers. A growing body of evidence suggests chronic cigarette smoking alone adversely affects neurocognition in adults. However, few studies on the neurocognitive function of short-term abstinent alcoholics have specifically considered the potential effects of chronic cigarette smoking. In this study, 20 nonsmoking recovering alcoholics (nsRA) and 22 actively smoking recovering alcoholics (sRA) participants, matched on age and education, were contrasted on a comprehensive neurocognitive battery after 34+/-9 days of abstinence. nsRA were superior to sRA on measures of auditory-verbal learning and memory, processing speed, cognitive efficiency, and static postural stability. These group differences were not a function of group disparities in age, education, estimated premorbid verbal intelligence, lifetime alcohol consumption, or other measured comorbid psychiatric or medical factors. In sRA, longer smoking duration was negatively correlated with executive skills, visuospatial learning, general cognitive efficiency, and static postural stability. These results indicate that greater consideration of the potential neurobiological effects of current chronic smoking on neurocognitive functioning is warranted in studies of alcoholism and other conditions where smoking is a common comorbid factor.
Adult↗
Learning to discriminate interaural time differences: an exploratory study with amplitude-modulated stimuli.
The advent of bilateral cochlear implants (CIs) has increased interest in learning on binaural tasks, and studies in normal-hearing listeners provide important background information. However, few studies have considered learning with discrimination of interaural time difference (ITD). Here, learning with ITD was explored using stimuli that are more relevant to bilateral CIs than used previously. Inexperienced listeners were trained with envelope-based ITD using high-frequency amplitude-modulated tones with or without an interaural carrier frequency difference (IFD), the former to simulate asymmetrical bilateral CI insertions. All were tested with and without IFD before and after training. In most listeners, ITD thresholds improved substantially with training, not necessarily reaching asymptote after 3,000 trials. In these, the magnitude and time-course of learning was larger than anticipated from a previous study with low-frequency ITD. Learning generalized across IFD and the effect of IFD on ITD thresholds at post-test was smaller than reported previously. These results have implications for studies of bilateral CIs, such as the need to provide extensive training to avoid over-estimating any apparent 'impairment'.
Acoustic Stimulation↗
Improvement and generalization of arm motor performance through motor imagery practice.
This study compares the improvement and generalization of arm motor performance after physical or mental training in a motor task requiring a speed-accuracy tradeoff. During the pre- and post-training sessions, 40 subjects pointed with their right arm as accurately and as fast as possible toward targets placed in the frontal plane. Arm movements were performed in two different workspaces called right and left paths. During the training sessions, which included only the right path, subjects were divided into four training groups (n = 10): (i) the physical group, subjects overtly performed the task; (ii) the mental group, subjects imagined themselves performing the task; (iii) the active control group, subjects performed eye movements through the targets, (iv) the passive control group, subjects did not receive any specific training. We recorded movement duration, peak acceleration and electromyographic signals from arm muscles. Our findings showed that after both physical and mental training on the right path (training path), hand movement duration and peak acceleration respectively decreased and increased for this path. However, motor performance improvement was greater after physical compared with mental practice. Interestingly, we also observed a partial learning generalization, namely an enhancement of motor performance for the left path (non-training path). The amount of this generalization was roughly similar for the physical and mental groups. Furthermore, while arm muscle activity progressively increased during the training period for the physical group, the activity of the same muscles for the mental group was unchanged and comparable with that of the rest condition. Control groups did not exhibit any improvement. These findings put forward the idea that mental training facilitates motor learning and allows its partial transfer to nearby workspaces. They further suggest that motor prediction, a common process during both actual and imagined movements, is a fundamental operation for both sensorimotor control and learning.
Adult↗
What do graduates think about a two-week rational pharmacotherapy course in the fifth year of medical education?
The present study aims to assess the short- and mid-term post-graduation impact of a pharmacotherapy course in the fifth year at Marmara University School of Medicine by an objective (OSCE) and a subjective (questionnaires) evaluation. Statistical comparison of pretest, posttest-exposed case and posttest-unexposed case scores indicated both a retention and a transfer effect of training. The post-course questionnaire revealed that 95%of the students found the course useful and necessary; 97% reported that they will apply a rational pharmacotherapy approach using this model and communicate better with their patients. The post-graduation questionnaire also showed that the majority of them have learned general principles of rational pharmacotherapy(90%), gained good prescribing (90%) and communication skills (87.5%), and understood the importance of non-pharmacological treatment alternatives (100%). In general, they stated that they would apply the principles during their medical practice and they believed their colleagues would do too. In conclusion, the present study demonstrates the benefit of a clinical pharmacology programme focused on rational pharmacotherapy during the clinical years of medical education.
Analysis of Variance↗
Oligo kernels for datamining on biological sequences: a case study on prokaryotic translation initiation sites.
BACKGROUND: Kernel-based learning algorithms are among the most advanced machine learning methods and have been successfully applied to a variety of sequence classification tasks within the field of bioinformatics. Conventional kernels utilized so far do not provide an easy interpretation of the learnt representations in terms of positional and compositional variability of the underlying biological signals. RESULTS: We propose a kernel-based approach to datamining on biological sequences. With our method it is possible to model and analyze positional variability of oligomers of any length in a natural way. On one hand this is achieved by mapping the sequences to an intuitive but high-dimensional feature space, well-suited for interpretation of the learnt models. On the other hand, by means of the kernel trick we can provide a general learning algorithm for that high-dimensional representation because all required statistics can be computed without performing an explicit feature space mapping of the sequences. By introducing a kernel parameter that controls the degree of position-dependency, our feature space representation can be tailored to the characteristics of the biological problem at hand. A regularized learning scheme enables application even to biological problems for which only small sets of example sequences are available. Our approach includes a visualization method for transparent representation of characteristic sequence features. Thereby importance of features can be measured in terms of discriminative strength with respect to classification of the underlying sequences. To demonstrate and validate our concept on a biochemically well-defined case, we analyze E. coli translation initiation sites in order to show that we can find biologically relevant signals. For that case, our results clearly show that the Shine-Dalgarno sequence is the most important signal upstream a start codon. The variability in position and composition we found for that signal is in accordance with previous biological knowledge. We also find evidence for signals downstream of the start codon, previously introduced as transcriptional enhancers. These signals are mainly characterized by occurrences of adenine in a region of about 4 nucleotides next to the start codon. CONCLUSIONS: We showed that the oligo kernel can provide a valuable tool for the analysis of relevant signals in biological sequences. In the case of translation initiation sites we could clearly deduce the most discriminative motifs and their positional variation from example sequences. Attractive features of our approach are its flexibility with respect to oligomer length and position conservation. By means of these two parameters oligo kernels can easily be adapted to different biological problems.
Algorithms↗
Interaction of brain noradrenaline and the pituitary-adrenal axis in learning and extinction.
The effect of 6-hydroxydopamine-induced degeneration of the dorsal tegmental noradrenergic (NA) projection alone or in combination with the removal of the adrenal glands was examined on several behavioral tasks. No impairment of acquisition on a continuously reinforced lever pressing response for food reward was seen as a result of the combined treatment. However, resistance to extinction was observed after depletion of forebrain noradrenaline on its own and this effect was prevented by the adrenalectomy. Adrenalectomy on its own failed to affect extinction. Acquisition of a passive avoidance task was slightly impaired after forebrain noradrenaline depletion but only the group with combined noradrenaline loss and adrenalectomy showed a 24 hour retention deficit. No alteration in shock thresholds was found in any group although both adrenalectomized groups consumed less food and were slightly less active in locomotor cages. It is suggested that previous reports of acquisition and retention deficits in avoidance tasks after combined dorsal NA bundle lesions and adrenalectomy are due to alterations in fear motivation rather than to a general learning impairment.
Animals↗
Active and passive avoidance learning in rats neonatally treated with intraventricular 6-hydroxydopamine.
To clarify the behavioral characteristics of rats neonatally treated with 6-hydroxydopamine (6-OHDA), their performance on 4 aversive learning tasks, 3 active (shuttle, one-way, and rearing) avoidance tasks and one passive (step-through) avoidance task, was examined. On days 2 and 4 after birth, each rat of F344/Du strain received bilateral intraventricular injections of 6-OHDA (35 micrograms x 2) or vehicle solution following desmethylimipramine (20 mg/kg, s.c.) pretreatment. From day 90, each rat was trained in one of the 4 avoidance tasks. 6-OHDA-treated rats showed significantly less avoidance responses in the shuttle and the one-way avoidance tasks, but their performance on the rearing and the step-through passive avoidance tasks was not significantly different from that of control rats. The differential impairment of avoidance suggests that 6-OHDA treatment does not cause a general learning deficit, but facilitates rearing and/or jumping responses in aversive situations, which results in inappropriate escape responses.
Animals↗
Measuring social behavior: social dominance.
Social dominance develops more slowly when young animals are kept in intact peer groups where they need not compete for resources. Learned generalizations may cause smaller and weaker animals to accept subordinate status readily when confronted with strangers that would be formidable opponents. Sexual hormones and sensitivity to them can influence the onset of aggression and status attained. After dominance orders are established, they tend to be stable in female groups but are less so in male groups. Psychological influences can affect dominance relationships when strangers meet and social alliances within groups may affect relative status of individuals. Whether status associated with agonistic behavior is correlated with control of space and scarce resources needs to be determined for each species and each kind of resource. When such correlations exists, competitive tests and agonistic behavior associated with gaining access to scarce resources can be useful to the observer in learning about dominance relationships rapidly. Examples are given to illustrate how estimates of social dominance can be readily attained and some strengths and weaknesses of the various methods.
Aggression↗
Actions and consequences in bimanual interaction are represented in different coordinate systems.
Moving one part of the body can generate interaction forces that tend to destabilize other parts of the body. However, stability is maintained by mechanisms that predict and actively oppose these interaction forces. When our body or environment changes, these anticipatory mechanisms adapt so as to continue to produce accurate predictions. In this study, we examine the acquisition of a novel predictive coordination between the arms, in a situation in which a force is produced on one hand as a consequence of the action of the other hand. Specifically, a force was applied to the left hand that depended on the velocity of the right hand. With practice, subjects learned to stabilize the perturbed left arm during right-arm movements by predicting and actively opposing the externally applied forces. After adaptation, we examined how learning generalized to a new joint configuration of the right or left arm to investigate the coordinate systems in which the internal transformation from movement to force is represented. This revealed a dissociation between the representation of the action of the right arm and the representation of its consequence, that is the force on the left arm. The movement is represented in extrinsic coordinates related to the velocity of the hand, whereas the force resulting from the movement is represented in a joint-based intrinsic coordinate system.
Adaptation, Physiological↗
Perceptual learning: psychophysical thresholds and electrical brain topography.
We studied perceptual learning by determining psychophysical discrimination thresholds for visual hyper acuity targets (vernier stimuli) as a function of stimulus orientation. One aim was to relate perceptual improvements to changes of electrophysiological activity of the human brain. A group of 43 healthy adults participated in a psychophysical experiment where vernier thresholds for vertical and horizontal vernier targets were compared. In 16 subjects thresholds were measured for each orientation twice at an interval of 25 min. Between threshold estimations, evoked brain activity was recorded from 30 electrodes over the occipital brain areas while the subjects observed appearance and disappearance of supra-threshold vernier offsets. Mean evoked potentials were computed for the first and second 600 stimulus presentations, and the scalp topography of electrical brain activity was analyzed. Vertically oriented stimuli yielded significantly better performance than horizontal targets, and thresholds were significantly lower in the second half of the experiment, i.e. after prolonged viewing of stimuli. The improvements in discrimination performance were specific for stimulus orientation and did not generalize. Learning effects were also observed with electrical brain activity, and field strength of the potentials increased significantly as a function of time. Scalp topography of the evoked components was significantly affected indicating a shift of activation between different neuronal elements induced by perceptual learning.
Adult↗
Enhancement of performance in multiple learning tasks by corticotropin-releasing factor-binding protein ligand inhibitors.
Evidence favors a role for corticotropin-releasing factor (CRF) in learning and memory processes. A binding protein (CRF-BP) with the ability to inactivate CRF provides a novel target to modulate endogenous levels of CRF. The present studies employed three measures of information processing in rats in order to examine the impact of CRF system activation resulting from administration of CRF-BP ligand inhibitors, which increase levels of "free CRF." Acquisition of a visual discrimination paradigm and retention of a inhibitory avoidance task were dose dependently facilitated by central administration of a CRF-BP ligand inhibitor. CRF-BP ligand inhibitor treatment also improved performance in an active avoidance paradigm in aged animals. No nonspecific anorexic effects of the active dose of CRF-BP ligand inhibitor were detected in a food intake test. Moreover, the magnitude of in vivo efficacy of the CRF-BP ligand inhibitor peptide in producing a mild increase in motor activity was dissociated from that of a postsynaptic CRF receptor agonist that exerted robust and long-lasting activity increases. Thus, CRF-BP ligand inhibitors appear to elicit generalized learning enhancement effects without mimicking the robust nonspecific behavioral actions of a CRF receptor agonist.
Animals↗
Fixed versus dynamic orientations in environmental learning from ground-level and aerial perspectives.
Ground-level and aerial perspectives in virtual space provide simplified conditions for investigating differences between exploratory navigation and map reading in large-scale environmental learning. General similarities and differences in ground-level and aerial encoding have been identified, but little is known about the specific characteristics that differentiate them. One such characteristic is the need to process orientation; ground-level encoding (and navigation) typically requires dynamic orientations, whereas aerial encoding (and map reading) is typically conducted in a fixed orientation. The present study investigated how this factor affected spatial processing by comparing ground-level and aerial encoding to a hybrid condition: aerial-with-turns. Experiment 1 demonstrated that scene recognition was sensitive to both perspective (ground-level or aerial) and orientation (dynamic or fixed). Experiment 2 investigated brain activation during encoding, revealing regions that were preferentially activated perspective as in previous studies (Shelton and Gabrieli in J Neurosci 22:2711-2717, 2002), but also identifying regions that were preferentially activated as a function of the presence or absence of turns. Together, these results differentiated the behavioral and brain consequences attributable to changes in orientation from those attributable to other characteristics of ground-level and aerial perspectives, providing leverage on how orientation information is processed in everyday spatial learning.
Adult↗