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PubMed2006

Perceptual learning with spatial uncertainties.

In perceptual learning, stimuli are usually assumed to be presented to a constant retinal location during training. However, due to tremor, drift, and microsaccades of the eyes, the same stimulus covers different retinal positions on sequential trials. Because of these variations the mathematical decision problem changes from linear to non-linear (). This non-linearity implies three predictions. First, varying the spatial position of a stimulus within a moderate range does not deteriorate perceptual learning. Second, improvement for one stimulus variant can yield negative transfer to other variants. Third, interleaved training with two stimulus variants yields no or strongly diminished learning. Using a bisection task, we found psychophysical evidence for the first and last prediction. However, no negative transfer was found as opposed to the second prediction.

Attention↗
PubMed2003

Is transfer of acquired coordination of head and forepaw movements possible in dogs?

Dogs were trained to tonic elevation of the forepaw and to use a lever to lift and maintain in position a food-containing cup during eating, this being accompanied by inclination of the head towards the feeder. In the conditions used here, the pretraining situation was that dogs would elevate the paw with an anticipatory upward movement of the lowered head; when the head tilted to the feeder, the paw flexed. The effect of special training, in which the initial coordination of the head and paw movements were remodeled, was that the animals maintained the paw elevated with the head in the lowered position. Dogs trained to perform the operant response with one paw did not transfer the acquired reaction when the "working" paw was changed. After the first training, the initial coordination was changed only between movements of the head and the "working" limb, but not between head movements and the non-trained paw. Remodeling of the initial movement coordination of the head with the second paw also occurred only as a result of the learning process.

Animals↗
PubMed2002

Object and spatial relational memory in adult rhesus monkeys is impaired by neonatal lesions of the hippocampal formation but not the amygdaloid complex.

Adult rhesus monkeys with neonatal aspiration lesions of the hippocampal formation or the amygdaloid complex (including their respective subjacent cortices) and their age-matched controls were tested on the transverse patterning problem (A+ vs. B-, B+ vs. C- and C+ vs. A-) and a spatial version of the delayed nonmatching-to-sample (DNMS) task with delays of 10 s to 30 s, 60 s, 120 s, and 600 s. Monkeys with neonatal damage to the amygdaloid complex learned both tasks and did not differ from controls at any delay of the spatial DNMS task. Monkeys with neonatal hippocampal damage, however, were unable to learn transverse patterning, though they easily transferred to a linear series (A+ vs. B-, B+ vs. C-, and C+ vs. X-). Three of the four were also unable to reach criterion on the spatial DNMS task within the limits of testing, and the performance of all four monkeys deteriorated with increasing choice delays. The data suggest a role of the primate hippocampal region in both object and spatial relational learning.

Aging↗
PubMed1987

Two years' experience of ultrasound-directed oocyte retrieval.

The first 2 years' data of an outpatient-based in vitro fertilization program relying on transabdominal transvesical ultrasound-directed oocyte retrieval (TUDOR) is presented. A total of 935 patients were treated. Ovarian stimulation was performed in 1538 cycles, oocyte retrieval in 1226, and embryo transfer in 960. All ovaries were accessible for oocyte retrieval, even in those patients in whom laparoscopic retrieval had failed previously or was deemed impossible. No major complications due to TUDOR occurred and the incidence of all complications was 1.5%. The clinical pregnancy rate was 19.0% per embryo transfer, but increased throughout the 2 years to 30.0% per embryo transfer. The technique is easy to learn, effective, and appears to be superior to laparoscopy in terms of ovarian accessibility and safety.

Chorionic Gonadotropin↗
PubMed1997

Virtual reality, disability and rehabilitation.

Virtual reality, or virtual environment computer technology, generates simulated objects and events with which people can interact. Existing and potential applications for this technology in the field of disability and rehabilitation are discussed. The main benefits identified for disabled people are that they can engage in a range of activities in a simulator relatively free from the limitations imposed by their disability, and they can do so in safety. Evidence that the knowledge and skills acquired by disabled individuals in simulated environments can transfer to the real world is presented. In particular, spatial information and life skills learned in a virtual environment have been shown to transfer to the real world. Applications for visually impaired people are discussed, and the potential for medical interventions and the assessment and treatment of neurological damage are considered. Finally some current limitations of the technology, and ethical concerns in relation to disability, are discussed.

Activities of Daily Living↗
PubMed1979

Interhemispheric engram transfer in chick.

Monocular training on a one-trial passive avoidance task in the young chick has been shown to establish an engram in the forebrain hemisphere contralateral to the trained eye, and hence interocular transfer of this task must involve the naive hemisphere making access to the engram in the opposite hemisphere. We have studied the consequences for the untrained hemisphere of accessing a unilateral engram during two short term stages of its consolidation, by conducting interocular transfer tests at 7.5 min and 30 min after learning, prior to onset of amnesia induced by intracranial injection of ouabain or cycloheximide. Testing the naive hemisphere 24 h later indicated that engram transfer had occurred in chicks receiving one access trial at 7.5 min, during the first stage of consolidation of the unilateral engram. At 30 min, during second consolidation stage, five access trials were required to achieve engram transfer. These experiments confirm the findings from the rat that engram transfer can follow from making access to the unilateral engram. However, it has not previously been recognised that interhemispheric memory transfer depends on the recency of formation of the unilateral engram.

Animals↗
PubMed1996

Pre-registration midwifery programmes: a case study evaluation of the non-midwifery placements.

OBJECTIVE: to evaluate the effectiveness of non-midwifery placements in enabling pre-registration (direct entry) student midwives to learn about caring for childbearing women with medical, surgical or mental health problems and needs. DESIGN: case study. SETTING: a large midwifery education department and three acute general hospitals in England. PARTICIPANTS: 15 student midwives in the first intake of one college's three-year diploma programme in midwifery plus the practitioners involved in their education. MAIN OUTCOME MEASURES: the learning needs of student midwives, who have no previous health-care experience, to enable them to care effectively for women with medical/surgical/mental health problems; the teaching processes and learning opportunities related to these aspects of care; how the views of teachers and practice placement staff compare with those of the students; the factors that influence the teaching and learning processes and experiences for pre-registration student midwives. FINDINGS: the broad range of experiences in medical/surgical/metal health placements enabled students to increase in maturity, and confidence and develop their communication skills. The variety of placements enhanced student understanding of the multi-disciplinary team's contribution to health care, students learned new practical skills which were transferable to maternity care contexts and all students had opportunities to care for adults with most of the medical/surgical/mental health problems seen in childbearing women. CONCLUSION: this action research project provided data for curriculum development and helped to avoid premature reaction to individual staff and student response. The value of the medical/surgical/mental health placements and the importance of staff and student preparation for effective learning was established. Whilst it might be essential to identify what and where student midwives should learn, it would appear that developing each student must be an equal, if not greater, priority for curriculum designers.

Adult↗
PubMed2001

Presence and reflection in training: support for learning to improve quality decision-making skills under time limitations.

Virtual Reality (VR) has been used for some time for training various skills. The results obtained are generally very reassuring, suggesting that Virtual Environments (VEs) are an effective new kind of educational tool. There are some, however, who argue that there are cases in which a 2D approach would achieve the same training effect. The literature suggests that the key features that distinguish VR from other training approaches is the sense of presence, which provides a first-person experience of the world. Usually, real world learning is multisensory and gives ownership and control over the experience, increases learner motivation, and triggers the construction of knowledge. Despite technical limitations, a VE is the most effective form of information technology for providing multisensory experience including visual, auditory, and to some extend haptic and tactile cues. The sense of presence ensures that the perceived experience is interpreted as being real and makes it likely that skills learned in the VE will be transferred to the real world. We argue that for training time-limited decision-making skills, the learner should also have an opportunity to reflect on actions/strategies to improve performance. Therefore a virtual environment for training should also provide support for students to reflect on their performance. This paper describes a prototype training system that aims to support both construction of knowledge and cognitive learning. It is also intended to trigger a sense of presence as well as provide support mechanisms, not available in the real world, that the students can exercise to reflect on the training experience.

Decision Making↗
PubMed2001

Hippocampal damage in rats disrupts decrements in the processing of an intramaze landmark in a spatial task.

Using a four-arm plus-shaped maze, rats with neurotoxic lesions in the dorsal hippocampus were trained in a spatial reference memory task in which both the extramaze constellation of stimuli and an intramaze landmark (a piece of sandpaper covering the floor of the goal) indicated the location of the goal arm. After reaching criterion, animals were given two transfer tests in order to investigate how much they had learned about the intra and extramaze cues. Results showed that during the intramaze transfer, based exclusively on the intramaze cue, hippocampal rats produced a performance clearly superior to that of the controls. Importantly, the average percentage of correct responses recorded in the hippocampal group during the extra versus the intramaze transfer test was similar. Thus, no decremental processing of the intramaze cue was detected in the lesioned group. In contrast, control rats showed a decremental processing of the intramaze landmark performing worse during the intramaze transfer as compared with the extramaze transfer. These results support the view that the hippocampus regulates decremental changes in the processing of normally irrelevant stimuli, extending this claim into a spatial domain.

Animals↗
PubMedDate not supplied

Generalization of learning in three-and-a-half-month-old infants on the basis of amodal relations.

Infants of 3.5 months (N = 124) were given the opportunity to learn to relate two objects and their natural, distinctive sounds during a training phase. The objects and sounds were united by temporal synchrony and amodal audiovisual information specifying object composition. Infants then participated in one of three types of transfer tests (requiring low, moderate, or high degrees of generalization) to measure the extent to which intermodal knowledge generalized to a new task and across events (familiar events; change in color/shape; change in substance, motion, and color/shape). Results indicated that infants tested with the familiar events and with events of a new color/shape showed learning and transfer of knowledge. In contrast, infants tested with events of a new substance, motion, and color/shape showed no generalization of learning. Thus, infants of 3.5 months appear to show a moderate degree of generalization of intermodal knowledge across events. Although this knowledge is not restricted to the events of original learning, it cannot yet be flexibly extended across a variety of contexts.

Auditory Perception↗
PubMed2001

Introduction to retroviruses and retroviral vectors.

As various viral vector systems for gene transfer are developed, interest in using such systems in applied settings continues to grow. This Chapter is designed to provide background information for readers interested in learning about lentiviral vector systems for gene transfer applications but who lack a background in retrovirology. To assist those readers who are unfamiliar with retroviral vector systems, basic outlines of the retroviral replication cycle and of characteristics of retroviral vector systems are introduced here in order to present and define concepts and terms that are discussed in subsequent Chapters.

Gene Transfer Techniques↗
PubMed1999

Transfer of value from S+ to S- in simultaneous discriminations in humans.

When animals learn a simultaneous discrimination, some of the value of the positive stimulus (S+) appears to transfer to the negative stimulus (S-). The present experiments demonstrate that such value transfer can also be found in humans. In Experiment 1 humans were trained on 2 simple simultaneous discriminations, the first between a highly positive stimulus, A (1,000 points); and a negative stimulus, B (0 points); and the second between a less positive stimulus, C (100 points); and a negative stimulus, D (0 points). On test trials, most participants preferred B over D. In Experiments 2 and 3 the value of the 2 original discriminations was equated in training (A[100]B[0] and C[100]D[0]). In Experiment 2 the values of the positive stimuli were then altered (A[1,000]C[0]); again, most participants preferred B over D. In Experiment 3, however, when the values of B and D were altered (B[1,000]D[0]), participants were indifferent to A and C. Thus, the mechanism that underlies value transfer in humans appears to be related to Pavlovian second-order conditioning. Similar mechanisms may be involved in assimilation processes in social contexts.

Adolescent↗
PubMed2004

Inter- and intralimb transfer of a bimanual task: generalisability of limb dissociation.

The present study examined whether the ability to dissociate bimanual limb movements following learning of a new coordination task (i.e. star-line drawing paradigm) can be generalised to different effector systems, as expressed by inter- and intralimb transfer. In Experiment 1, subjects practised the 'Line-Star' task (i.e. left arm traced the line/right arm traced the star) and then transferred this pattern to its symmetry partner: the 'Star-Line' task (left arm star/right arm line). In Experiment 2, intralimb transfer from the shoulder-elbow (proximal) to the wrist-finger joints (distal), and vice versa, was investigated. Results revealed positive interlimb transfer among symmetry partners of the star-line movement. Moreover, learning the star-line task spontaneously transferred from the trained to the untrained effector system whereby proximal to distal transfer was larger than vice versa. It is concluded that learning to spatially dissociate the movements of both limbs is generalisable to different motor conditions even though transfer to some conditions is suboptimal. It is hypothesised that the nature of the representation of the spatial interference task is largely effector independent.

Adult↗
PubMed2001

Benefits of collaborative learning for environmental management: applying the integrated systems for knowledge management approach to support animal pest control.

Resource management issues continually change over time in response to coevolving social, economic, and ecological systems. Under these conditions adaptive management, or "learning by doing," offers an opportunity for more proactive and collaborative approaches to resolving environmental problems. In turn, this will require the implementation of learning-based extension approaches alongside more traditional linear technology transfer approaches within the area of environmental extension. In this paper the Integrated Systems for Knowledge Management (ISKM) approach is presented to illustrate how such learning-based approaches can be used to help communities develop, apply, and refine technical information within a larger context of shared understanding. To outline how this works in practice, we use a case study involving pest management. Particular attention is paid to the issues that emerge as a result of multiple stakeholder involvement within environmental problem situations. Finally, the potential role of the Internet in supporting and disseminating the experience gained through ongoing adaptive management processes is examined.

Animals↗
PubMed2005

Optimizing the number of steps in learning tasks for complex skills.

BACKGROUND: Carrying out whole tasks is often too difficult for novice learners attempting to acquire complex skills. The common solution is to split up the tasks into a number of smaller steps. The number of steps must be optimized for efficient and effective learning. AIM: The aim of the study is to investigate the relation between the number of steps provided to learners and the quality of their learning of complex skills. It is hypothesized that students receiving an optimized number of steps will learn better than those receiving either the whole task in only one step or those receiving a large number of steps. SAMPLE: Participants were 35 sophomore law students studying at Dutch universities, mean age=22.8 years (SD=3.5), 63% were female. METHOD: Participants were randomly assigned to 1 of 3 computer-delivered versions of a multimedia programme on how to prepare and carry out a law plea. The versions differed only in the number of learning steps provided. Videotaped plea-performance results were determined, various related learning measures were acquired and all computer actions were logged and analyzed. RESULTS: Participants exposed to an intermediate (i.e. optimized) number of steps outperformed all others on the compulsory learning task. No differences in performance on a transfer task were found. A high number of steps proved to be less efficient for carrying out the learning task. CONCLUSIONS: An intermediate number of steps is the most effective, proving that the number of steps can be optimized for improving learning.

Adult↗
PubMed2003

Motor evoked potentials of the lower extremity in predicting motor recovery and ambulation after stroke: a cohort study.

OBJECTIVE: To assess the prognostic value of motor evoked potentials (MEPs) in the lower extremity with respect to motor recovery and functional recovery in stroke patients. DESIGN: Cohort study. SETTING: The department of neurology at a university hospital. PARTICIPANTS: Thirty-eight acute-stroke patients with complete paralysis (paralysis subgroup) or severe paresis (paresis subgroup) of the lower extremity. MEPs of the vastus medialis and the tibialis anterior muscles were recorded between days 3 and 10 after stroke onset. INTERVENTIONS: Not applicable. Main outcome measures A separate proximal leg motor score (maximum, 16 points) and crural motor score (maximum, 2 points) were defined within the lower-limb subset of the original Fugl-Meyer Motor Assessment to evaluate the motor performance at regular intervals until 6 months after stroke. The transfer item of the Barthel Index and the Functional Ambulation Categories scores were used to assess transfer and walking ability. RESULTS: For the paralysis subgroup (n=30), the follow-up was complete in 27 patients (2 patients died, 1 patient underwent above-knee amputation). At 26 weeks, 20 patients experienced proximal motor recovery (mean score +/- standard deviation, 11.70+/-4.48), and 12 of them also showed crural motor recovery (mean score, 1.40+/-.51). Nine patients (33%) could perform an independent transfer safely, and 7 (26%) had learned to walk independently. Analysis revealed significant relationships for tibialis anterior muscle MEPs and motor recovery of crural leg muscles (odds ratio [OR]=18.00; 95% confidence interval [CI], 1.31-894.40), but not for vastus medialis muscle MEPs and proximal motor recovery (OR=6.00; 95% CI,.53-303.00). We found no association between vastus medialis muscle MEPs and recovery of ambulation. However, tibialis anterior muscle MEPs seemed to provide a test with prognostic value for the ability to perform independent transfers (OR=17.50; 95% CI, 1.36-267.00), but not for walking (OR=5.25; 95% CI,.40-77.57). Patients in the paresis subgroup experienced more favorable motor and functional recovery than did those in the paralysis subgroup. CONCLUSIONS: Tibialis anterior muscle MEPs registered in subacute phase after stroke may provide important prognostic information, both for motor recovery of the crural muscles and for the ability to perform independent transfers in patients with initial complete paralysis of the lower extremity. Vastus medialis muscle MEPs were not predictive for motor and functional recovery.

Adult↗
PubMed2006

What do, can and should we learn from models to evaluate potential anticancer agents?

Transfer of new anticancer agents from bench to clinical trial takes in excess of 10 years and costs up to US $500 million. Despite this massive commitment, many more new agents fail in the clinical trials than are successful. The poor performance of many investigational anticancer agents in the clinic implies that the preclinical models used to evaluate them are flawed, inappropriately used or the information they generate is misinterpreted. This article reviews current practice and the range of preclinical models available. The author provides a personal perspective on what information is needed and how in the future this might best be obtained from preclinical models to more effectively inform the transfer of novel, active agents into clinical practice.

Animals↗