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Sample records for stable associative learning

  1. Rapid Associative Learning and Stable Long-Term Memory in the Squid Euprymna scolopes.

    Science.gov (United States)

    Zepeda, Emily A; Veline, Robert J; Crook, Robyn J

    2017-06-01

    Learning and memory in cephalopod molluscs have received intensive study because of cephalopods' complex behavioral repertoire and relatively accessible nervous systems. While most of this research has been conducted using octopus and cuttlefish species, there has been relatively little work on squid. Euprymna scolopes Berry, 1913, a sepiolid squid, is a promising model for further exploration of cephalopod cognition. These small squid have been studied in detail for their symbiotic relationship with bioluminescent bacteria, and their short generation time and successful captive breeding through multiple generations make them appealing models for neurobiological research. However, little is known about their behavior or cognitive ability. Using the well-established "prawn-in-the-tube" assay of learning and memory, we show that within a single 10-min trial E. scolopes learns to inhibit its predatory behavior, and after three trials it can retain this memory for at least 12 d. Rapid learning and very long-term retention were apparent under two different training schedules. To our knowledge, this study is the first demonstration of learning and memory in this species as well as the first demonstration of associative learning in any squid.

  2. Associative Learning Should Go Deep.

    Science.gov (United States)

    Mondragón, Esther; Alonso, Eduardo; Kokkola, Niklas

    2017-11-01

    Conditioning, how animals learn to associate two or more events, is one of the most influential paradigms in learning theory. It is nevertheless unclear how current models of associative learning can accommodate complex phenomena without ad hoc representational assumptions. We propose to embrace deep neural networks to negotiate this problem. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. ERP correlates of associative learning.

    Science.gov (United States)

    Rose, M; Verleger, R; Wascher, E

    2001-05-01

    We examined changes of event-related potentials (ERPs) while participants learned stimulus-to-stimulus relations in an S1-S2 task. The design allowed for separating processes of associative learning from nonspecific effects. Participants had to respond to S2 by a left or right key-press dependent on S2 identity (letter W or M). Preparation for S2 could be improved by using the associative information given by S1. The S1 was an arrow pointing to the left or right. In combination with its color, arrow direction was informative about location and identity of S2, but participants were not informed about the relevance of color. Arrows in two of the colors were fully predictive for the S2 whereas the third color gave no valid information. This third stimulus controlled for habituation and procedural learning. Six blocks with 200 trials each and all three S1 colors in random order were presented. Behavioral and ERP differences in each block between "learning" and control trials were used to identify processes of associative learning. Several effects of associative learning were identified indicating the involvement of specific stages of information processing: a continuous increase of P3 amplitude evoked by S1 was accompanied by a decrease of P3 evoked by S2. These changes reflected the modifications of stimulus weights for response selection and the strengthened association between the two stimulus complexes in the time course of learning. The related motor preparation benefited from learning too, expressed in a decrease of CNV amplitude and an increase of LRP amplitude. Finally a decrease of N1 amplitude evoked by S2 indicated the reduced need to allocate spatial attention to the S2 location according to the learned meaning of S1.

  4. Predicting non-linear dynamics by stable local learning in a recurrent spiking neural network.

    Science.gov (United States)

    Gilra, Aditya; Gerstner, Wulfram

    2017-11-27

    The brain needs to predict how the body reacts to motor commands, but how a network of spiking neurons can learn non-linear body dynamics using local, online and stable learning rules is unclear. Here, we present a supervised learning scheme for the feedforward and recurrent connections in a network of heterogeneous spiking neurons. The error in the output is fed back through fixed random connections with a negative gain, causing the network to follow the desired dynamics. The rule for Feedback-based Online Local Learning Of Weights (FOLLOW) is local in the sense that weight changes depend on the presynaptic activity and the error signal projected onto the postsynaptic neuron. We provide examples of learning linear, non-linear and chaotic dynamics, as well as the dynamics of a two-link arm. Under reasonable approximations, we show, using the Lyapunov method, that FOLLOW learning is uniformly stable, with the error going to zero asymptotically.

  5. The Founding of the Learning Communities Association

    Science.gov (United States)

    Huerta, Juan Carlos

    2017-01-01

    Learning communities have reached the point in their growth that we now need a professional association to allow for more opportunities for participation in advancing learning communities. This is the story of the founding of the new Learning Communities Association.

  6. Symmetry of learning rate in synaptic plasticity modulates formation of flexible and stable memories.

    Science.gov (United States)

    Park, Youngjin; Choi, Woochul; Paik, Se-Bum

    2017-07-18

    Spike-timing-dependent plasticity (STDP) is considered critical to learning and memory functions in the human brain. Across various types of synapse, STDP is observed as different profiles of Hebbian and anti-Hebbian learning rules. However, the specific roles of diverse STDP profiles in memory formation still remain elusive. Here, we show that the symmetry of the learning rate profile in STDP is crucial to determining the character of stored memory. Using computer simulations, we found that an asymmetric learning rate generates flexible memory that is volatile and easily overwritten by newly appended information. Moreover, a symmetric learning rate generates stable memory that can coexist with newly appended information. In addition, by combining these two conditions, we could realize a hybrid memory type that operates in a way intermediate between stable and flexible memory. Our results demonstrate that various attributes of memory functions may originate from differences in the synaptic stability.

  7. Mirror Neurons from Associative Learning

    OpenAIRE

    Catmur, Caroline; Press, Clare; Heyes, Cecilia

    2016-01-01

    Mirror neurons fire both when executing actions and observing others perform similar actions. Their sensorimotor matching properties have generally been considered a genetic adaptation for social cognition; however, in the present chapter we argue that the evidence in favor of this account is not compelling. Instead we present evidence supporting an alternative account: that mirror neurons’ matching properties arise from associative learning during individual development. Notably, this proces...

  8. The endocannabinoid system and associative learning and memory in zebrafish.

    Science.gov (United States)

    Ruhl, Tim; Moesbauer, Kirstin; Oellers, Nadine; von der Emde, Gerhard

    2015-09-01

    In zebrafish the medial pallium of the dorsal telencephalon represents an amygdala homolog structure, which is crucially involved in emotional associative learning and memory. Similar to the mammalian amygdala, the medial pallium contains a high density of endocannabinoid receptor CB1. To elucidate the role of the zebrafish endocannabinoid system in associative learning, we tested the influence of acute and chronic administration of receptor agonists (THC, WIN55,212-2) and antagonists (Rimonabant, AM-281) on two different learning paradigms. In an appetitively motivated two-alternative choice paradigm, animals learned to associate a certain color with a food reward. In a second set-up, a fish shuttle-box, animals associated the onset of a light stimulus with the occurrence of a subsequent electric shock (avoidance conditioning). Once fish successfully had learned to solve these behavioral tasks, acute receptor activation or inactivation had no effect on memory retrieval, suggesting that established associative memories were stable and not alterable by the endocannabinoid system. In both learning tasks, chronic treatment with receptor antagonists improved acquisition learning, and additionally facilitated reversal learning during color discrimination. In contrast, chronic CB1 activation prevented aversively motivated acquisition learning, while different effects were found on appetitively motivated acquisition learning. While THC significantly improved behavioral performance, WIN55,212-2 significantly impaired color association. Our findings suggest that the zebrafish endocannabinoid system can modulate associative learning and memory. Stimulation of the CB1 receptor might play a more specific role in acquisition and storage of aversive learning and memory, while CB1 blocking induces general enhancement of cognitive functions. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Learning Disabilities Association of America

    Science.gov (United States)

    ... for information on learning disabilities. Learn more about: Auditory Processing Disorder Dyscalculia Dysgraphia Dyslexia Dyspraxia Language Processing Disorder Non-Verbal Learning Disabilities Visual Perceptual/Visual Motor Deficit Memory ADHD Executive Functioning Parents LD/ADHD Basics Assessment & ...

  10. Behavioural responses of stable flies to cattle manure slurry associated odourants

    Science.gov (United States)

    Stable flies (Stomoxys calcitrans [Diptera: Muscidae] L.) are blood-feeding synanthropic pests, which cause significant economic losses in livestock. Stable fly antennae contain olfactory sensilla responsive to host and host environment-associated odours. Field observation indicated that the abundan...

  11. Persistent and stable biases in spatial learning mechanisms predict navigational style.

    Science.gov (United States)

    Furman, Andrew J; Clements-Stephens, Amy M; Marchette, Steven A; Shelton, Amy L

    2014-12-01

    A wealth of evidence in rodents and humans supports the central roles of two learning systems--hippocampal place learning and striatal response learning--in the formation of spatial representations to support navigation. Individual differences in the ways that these mechanisms are engaged during initial encoding and subsequent navigation may provide a powerful framework for explaining the wide range of variability found in the strategies and solutions that make up human navigational styles. Previous work has revealed that activation in the hippocampal and striatal networks during learning could predict navigational style. Here, we used functional magnetic resonance imaging to investigate the relative activations in these systems during both initial encoding and the act of dynamic navigation in a learned environment. Participants learned a virtual environment and were tested on subsequent navigation to targets within the environment. We observed that a given individual had a consistent balance of memory system engagement across both initial encoding and subsequent navigation, a balance that successfully predicted the participants' tendencies to use novel shortcuts versus familiar paths during dynamic navigation. This was further supported by the observation that the activation during subsequent retrieval was not dependent on the type of solution used on a given trial. Taken together, our results suggest a model in which the place- and response-learning systems are present in parallel to support a variety of navigational behaviors, but stable biases in the engagement of these systems influence what solutions might be available for any given individual.

  12. Differential Associations Between Specific Depressive Symptoms and Cardiovascular Prognosis in Patients With Stable Coronary Heart Disease

    NARCIS (Netherlands)

    Hoen, Petra W.; Whooley, Mary A.; Martens, Elisabeth J.; Na, Beeya; van Melle, Joost P.; de Jonge, Peter

    2010-01-01

    Objectives The purpose of this research was to evaluate the relationship between cognitive and somatic depressive symptoms and cardiovascular prognosis. Background Depression in patients with stable coronary heart disease (CHD) is associated with poor cardiac prognosis. Whether certain depressive

  13. Stable cellular senescence is associated with persistent DDR activation.

    Science.gov (United States)

    Fumagalli, Marzia; Rossiello, Francesca; Mondello, Chiara; d'Adda di Fagagna, Fabrizio

    2014-01-01

    The DNA damage response (DDR) is activated upon DNA damage generation to promote DNA repair and inhibit cell cycle progression in the presence of a lesion. Cellular senescence is a permanent cell cycle arrest characterized by persistent DDR activation. However, some reports suggest that DDR activation is a feature only of early cellular senescence that is then lost with time. This challenges the hypothesis that cellular senescence is caused by persistent DDR activation. To address this issue, we studied DDR activation dynamics in senescent cells. Here we show that normal human fibroblasts retain DDR markers months after replicative senescence establishment. Consistently, human fibroblasts from healthy aged donors display markers of DDR activation even three years in culture after entry into replicative cellular senescence. However, by extending our analyses to different human cell strains, we also observed an apparent DDR loss with time following entry into cellular senescence. This though correlates with the inability of these cell strains to survive in culture upon replicative or irradiation-induced cellular senescence. We propose a model to reconcile these results. Cell strains not suffering the prolonged in vitro culture stress retain robust DDR activation that persists for years, indicating that under physiological conditions persistent DDR is causally involved in senescence establishment and maintenance. However, cell strains unable to maintain cell viability in vitro, due to their inability to cope with prolonged cell culture-associated stress, show an only-apparent reduction in DDR foci which is in fact due to selective loss of the most damaged cells.

  14. Implicit associative learning in synesthetes and nonsynesthetes.

    Science.gov (United States)

    Bankieris, Kaitlyn R; Aslin, Richard N

    2017-06-01

    Although cross-modal neural connections and genetic underpinnings are prominent in most current theories regarding the development of synesthesia, the potential role of associative learning in the formation of synesthetic associations has recently been revitalized. In this study, we investigated implicit associative learning in synesthetes and nonsynesthetes by recording reaction times to a target whose color was probabilistically correlated with its shape. A continuous measure of target detection at multiple time points during learning revealed that synesthetes and nonsynesthetes learn associations differently. Specifically, our results demonstrated a "fast-facilitation" learning effect for nonsynesthetes and a "fast-interference, slow-facilitation" learning effect for synesthetes. Additionally, synesthetes exhibited superior long-term memory for the learned associations in a surprise delayed retest. After this retest, participants implicitly learned new (shuffled) shape-color associations. We found that synesthetes experienced greater interference while learning these new shape-color associations. These results detail ways in which implicit associative learning and memory differ between synesthetes and nonsynesthetes.

  15. Discrete-Time Stable Generalized Self-Learning Optimal Control With Approximation Errors.

    Science.gov (United States)

    Wei, Qinglai; Li, Benkai; Song, Ruizhuo

    2018-04-01

    In this paper, a generalized policy iteration (GPI) algorithm with approximation errors is developed for solving infinite horizon optimal control problems for nonlinear systems. The developed stable GPI algorithm provides a general structure of discrete-time iterative adaptive dynamic programming algorithms, by which most of the discrete-time reinforcement learning algorithms can be described using the GPI structure. It is for the first time that approximation errors are explicitly considered in the GPI algorithm. The properties of the stable GPI algorithm with approximation errors are analyzed. The admissibility of the approximate iterative control law can be guaranteed if the approximation errors satisfy the admissibility criteria. The convergence of the developed algorithm is established, which shows that the iterative value function is convergent to a finite neighborhood of the optimal performance index function, if the approximate errors satisfy the convergence criterion. Finally, numerical examples and comparisons are presented.

  16. Danish stable schools for experiential common learning in groups of organic dairy farmers

    DEFF Research Database (Denmark)

    Waarst, M.; Nissen, T.B; Østergaard, I.

    2007-01-01

    The farmer field school (FFS) is a concept for farmers' learning, knowledge exchange, and empowerment that has been developed and used in developing countries. In Denmark, a research project focusing on explicit non-antibiotic strategies involves farmers who have actively expressed an interest...... and in this context, problems were identified and solutions proposed based on each farmer's individual goals. In this article, we describe the experiences of 4 stable school groups (each comprising farmers and a facilitator), and the common process of building a concept that is suitable for Danish organic dairy...

  17. Learning rules for aversive associative memory formation.

    Science.gov (United States)

    Ozawa, Takaaki; Johansen, Joshua P

    2018-03-05

    For survival, organisms need the ability to flexibly modify their behavior. To achieve this, the brain is equipped with instructive brain circuits which trigger changes in neural connectivity and adaptive changes in behavior in response to environmental/internal challenges. Recent studies using a form of aversive associative learning termed fear conditioning have shed light on the neural mechanisms of instructive signaling. These studies demonstrate that fear learning is engaged through multiple, parallel aversive signaling pathways to the amygdala. Consistent with theoretical accounts of learning, activity in these circuits and behavioral learning is tightly regulated by the predictability of the aversive experience. However, in more complex learning conditions, these emotion circuits use a form of inference to approximate the appropriate reaction to danger. This suggests a revised view of how emotional learning systems represent aversive associations and how changes in these representations are instructed during learning. Copyright © 2018 Elsevier Ltd. All rights reserved.

  18. Tailor-made memory: natural differences in associative olfactory learning in two closely related wasp species

    NARCIS (Netherlands)

    Berg, van den M.

    2009-01-01

    Learning and memory formation are often seen as traits that are purely beneficial, but they are associated with metabolic costs as well. Since costs and gains of learning and memory are expected to vary between species, the ease and speed with which stable (consolidated) long-term memory (LTM) is

  19. Stable Myoelectric Control of a Hand Prosthesis using Non-Linear Incremental Learning

    Directory of Open Access Journals (Sweden)

    Arjan eGijsberts

    2014-02-01

    Full Text Available Stable myoelectric control of hand prostheses remains an open problem. The only successful human-machine interface is surface electromyography, typically allowing control of a few degrees of freedom. Machine learning techniques may have the potential to remove these limitations, but their performance is thus far inadequate: myoelectric signals change over time under the influence of various factors, deteriorating control performance. It is therefore necessary, in the standard approach, to regularly retrain a new model from scratch.We hereby propose a non-linear incremental learning method in which occasional updates with a modest amount of novel training data allow continual adaptation to the changes in the signals. In particular, Incremental Ridge Regression and an approximation of the Gaussian Kernel known as Random Fourier Features are combined to predict finger forces from myoelectric signals, both finger-by-finger and grouped in grasping patterns.We show that the approach is effective and practically applicable to this problem by first analyzing its performance while predicting single-finger forces. Surface electromyography and finger forces were collected from 10 intact subjects during four sessions spread over two different days; the results of the analysis show that small incremental updates are indeed effective to maintain a stable level of performance.Subsequently, we employed the same method on-line to teleoperate a humanoid robotic arm equipped with a state-of-the-art commercial prosthetic hand. The subject could reliably grasp, carry and release everyday-life objects, enforcing stable grasping irrespective of the signal changes, hand/arm movements and wrist pronation and supination.

  20. Stable Sparse Classifiers Identify qEEG Signatures that Predict Learning Disabilities (NOS Severity

    Directory of Open Access Journals (Sweden)

    Jorge Bosch-Bayard

    2018-01-01

    Full Text Available In this paper, we present a novel methodology to solve the classification problem, based on sparse (data-driven regressions, combined with techniques for ensuring stability, especially useful for high-dimensional datasets and small samples number. The sensitivity and specificity of the classifiers are assessed by a stable ROC procedure, which uses a non-parametric algorithm for estimating the area under the ROC curve. This method allows assessing the performance of the classification by the ROC technique, when more than two groups are involved in the classification problem, i.e., when the gold standard is not binary. We apply this methodology to the EEG spectral signatures to find biomarkers that allow discriminating between (and predicting pertinence to different subgroups of children diagnosed as Not Otherwise Specified Learning Disabilities (LD-NOS disorder. Children with LD-NOS have notable learning difficulties, which affect education but are not able to be put into some specific category as reading (Dyslexia, Mathematics (Dyscalculia, or Writing (Dysgraphia. By using the EEG spectra, we aim to identify EEG patterns that may be related to specific learning disabilities in an individual case. This could be useful to develop subject-based methods of therapy, based on information provided by the EEG. Here we study 85 LD-NOS children, divided in three subgroups previously selected by a clustering technique over the scores of cognitive tests. The classification equation produced stable marginal areas under the ROC of 0.71 for discrimination between Group 1 vs. Group 2; 0.91 for Group 1 vs. Group 3; and 0.75 for Group 2 vs. Group1. A discussion of the EEG characteristics of each group related to the cognitive scores is also presented.

  1. Animal social learning: associations and adaptations.

    Science.gov (United States)

    Reader, Simon M

    2016-01-01

    Social learning, learning from others, is a powerful process known to impact the success and survival of humans and non-human animals alike. Yet we understand little about the neurocognitive and other processes that underpin social learning. Social learning has often been assumed to involve specialized, derived cognitive processes that evolve and develop independently from other processes. However, this assumption is increasingly questioned, and evidence from a variety of organisms demonstrates that current, recent, and early life experience all predict the reliance on social information and thus can potentially explain variation in social learning as a result of experiential effects rather than evolved differences. General associative learning processes, rather than adaptive specializations, may underpin much social learning, as well as social learning strategies. Uncovering these distinctions is important to a variety of fields, for example by widening current views of the possible breadth and adaptive flexibility of social learning. Nonetheless, just like adaptationist evolutionary explanations, associationist explanations for social learning cannot be assumed, and empirical work is required to uncover the mechanisms involved and their impact on the efficacy of social learning. This work is being done, but more is needed. Current evidence suggests that much social learning may be based on 'ordinary' processes but with extraordinary consequences.

  2. Prefrontal Dopamine in Associative Learning and Memory

    Science.gov (United States)

    Puig, M. Victoria; Antzoulatos, Evan G.; Miller, Earl K.

    2014-01-01

    Learning to associate specific objects or actions with rewards and remembering the associations are everyday tasks crucial for our flexible adaptation to the environment. These higher-order cognitive processes depend on the prefrontal cortex (PFC) and frontostriatal circuits that connect areas in the frontal lobe with the striatum in the basal ganglia. Both structures are densely innervated by dopamine (DA) afferents that originate in the midbrain. Although the activity of DA neurons is thought to be important for learning, the exact role of DA transmission in frontostriatal circuits during learning-related tasks is still unresolved. Moreover, the neural substrates of this modulation are poorly understood. Here, we review our recent work in monkeys utilizing local pharmacology of DA agents in the PFC to investigate the cellular mechanisms of DA modulation of associative learning and memory. We show that blocking both D1 and D2 receptors in the lateral PFC impairs learning of new stimulus-response associations and cognitive flexibility, but not the memory of highly familiar associations. In addition, D2 receptors may also contribute to motivation. The learning deficits correlated with reductions of neural information about the associations in PFC neurons, alterations in global excitability and spike synchronization, and exaggerated alpha and beta neural oscillations. Our findings provide new insights into how DA transmission modulate associative learning and memory processes in frontostriatal systems. PMID:25241063

  3. Association between Nitrogen Stable Isotope Ratios in Human Hair and Serum Levels of Leptin.

    Science.gov (United States)

    Ahn, Song Vogue; Koh, Sang-Baek; Lee, Kwang-Sik; Bong, Yeon-Sik; Park, Jong-Ku

    2017-10-01

    Stable isotope ratios have been reported to be potential biomarkers of dietary intake and nutritional status. High serum levels of leptin, a hormone which regulates energy metabolism and food intake, are associated with insulin resistance and metabolic syndrome. However, little is known about the association between stable isotope ratios and the metabolic risk in humans. We investigated whether the carbon and nitrogen stable isotope ratios in hair are associated with serum leptin levels. Hair samples were collected from 399 healthy adults (233 men and 166 women) aged 40 to 70 years of a community-based cohort in Korea and the bulk stable isotope ratios of carbon (δ 13 C) and nitrogen (δ 15 N) were measured for all hair samples. Serum leptin levels were analyzed by radioimmunoassay. δ 15 N showed positive correlations with serum leptin levels. In multivariate models, increasing δ 15 N were associated with elevated serum leptin levels (defined as ≥ the median values), whereas δ 13 C were not significantly associated with serum leptin levels. The odds ratio (95% confidence interval) per 1‰ increase in δ 15 N for an elevated serum leptin level was 1.58 (1.11-2.26). In participants with high body mass index, δ 15 N showed positive associations with serum leptin levels, whereas these associations were not seen in participants with low body mass index. The nitrogen stable isotopic ratio in hair is positively associated with serum leptin levels. The hair δ 15 N could be used as a clinical marker to estimate metabolic risk.

  4. Application of Machine-Learning Models to Predict Tacrolimus Stable Dose in Renal Transplant Recipients

    Science.gov (United States)

    Tang, Jie; Liu, Rong; Zhang, Yue-Li; Liu, Mou-Ze; Hu, Yong-Fang; Shao, Ming-Jie; Zhu, Li-Jun; Xin, Hua-Wen; Feng, Gui-Wen; Shang, Wen-Jun; Meng, Xiang-Guang; Zhang, Li-Rong; Ming, Ying-Zi; Zhang, Wei

    2017-02-01

    Tacrolimus has a narrow therapeutic window and considerable variability in clinical use. Our goal was to compare the performance of multiple linear regression (MLR) and eight machine learning techniques in pharmacogenetic algorithm-based prediction of tacrolimus stable dose (TSD) in a large Chinese cohort. A total of 1,045 renal transplant patients were recruited, 80% of which were randomly selected as the “derivation cohort” to develop dose-prediction algorithm, while the remaining 20% constituted the “validation cohort” to test the final selected algorithm. MLR, artificial neural network (ANN), regression tree (RT), multivariate adaptive regression splines (MARS), boosted regression tree (BRT), support vector regression (SVR), random forest regression (RFR), lasso regression (LAR) and Bayesian additive regression trees (BART) were applied and their performances were compared in this work. Among all the machine learning models, RT performed best in both derivation [0.71 (0.67-0.76)] and validation cohorts [0.73 (0.63-0.82)]. In addition, the ideal rate of RT was 4% higher than that of MLR. To our knowledge, this is the first study to use machine learning models to predict TSD, which will further facilitate personalized medicine in tacrolimus administration in the future.

  5. Associative learning for a robot intelligence

    CERN Document Server

    Andreae, John H

    1998-01-01

    The explanation of brain functioning in terms of the association of ideas has been popular since the 17th century. Recently, however, the process of association has been dismissed as computationally inadequate by prominent cognitive scientists. In this book, a sharper definition of the term "association" is used to revive the process by showing that associative learning can indeed be computationally powerful. Within an appropriate organization, associative learning can be embodied in a robot to realize a human-like intelligence, which sets its own goals, exhibits unique unformalizable behaviou

  6. A calcium-dependent plasticity rule for HCN channels maintains activity homeostasis and stable synaptic learning.

    Science.gov (United States)

    Honnuraiah, Suraj; Narayanan, Rishikesh

    2013-01-01

    for experimentally observed plasticity in HCN channels accompanying synaptic plasticity in hippocampal neurons, and uncover potential links between HCN-channel plasticity and calcium influx, dynamic gain control and stable synaptic learning.

  7. A calcium-dependent plasticity rule for HCN channels maintains activity homeostasis and stable synaptic learning.

    Directory of Open Access Journals (Sweden)

    Suraj Honnuraiah

    physiological roles for experimentally observed plasticity in HCN channels accompanying synaptic plasticity in hippocampal neurons, and uncover potential links between HCN-channel plasticity and calcium influx, dynamic gain control and stable synaptic learning.

  8. A Calcium-Dependent Plasticity Rule for HCN Channels Maintains Activity Homeostasis and Stable Synaptic Learning

    Science.gov (United States)

    Honnuraiah, Suraj; Narayanan, Rishikesh

    2013-01-01

    for experimentally observed plasticity in HCN channels accompanying synaptic plasticity in hippocampal neurons, and uncover potential links between HCN-channel plasticity and calcium influx, dynamic gain control and stable synaptic learning. PMID:23390543

  9. Adaptive learning in a compartmental model of visual cortex - how feedback enables stable category learning and refinement

    Directory of Open Access Journals (Sweden)

    Georg eLayher

    2014-12-01

    Full Text Available The categorization of real world objects is often reflected in the similarity of their visual appearances. Such categories of objects do not necessarily form disjunct sets of objects, neither semantically nor visually. The relationship between categories can often be described in terms of a hierarchical structure. For instance, tigers and leopards build two separate mammalian categories, but both belong to the category of felines. In other words, tigers and leopards are subcategories of the category Felidae. In the last decades, the unsupervised learning of categories of visual input stimuli has been addressed by numerous approaches in machine learning as well as in the computational neurosciences. However, the question of what kind of mechanisms might be involved in the process of subcategory learning, or category refinement, remains a topic of active investigation. We propose a recurrent computational network architecture for the unsupervised learning of categorial and subcategorial visual input representations. During learning, the connection strengths of bottom-up weights from input to higher-level category representations are adapted according to the input activity distribution. In a similar manner, top-down weights learn to encode the characteristics of a specific stimulus category. Feedforward and feedback learning in combination realize an associative memory mechanism, enabling the selective top-down propagation of a category's feedback weight distribution. We suggest that the difference between the expected input encoded in the projective field of a category node and the current input pattern controls the amplification of feedforward-driven representations. Large enough differences trigger the recruitment of new representational resources and the establishment of (sub- category representations. We demonstrate the temporal evolution of such learning and show how the approach successully establishes category and subcategory

  10. Visual attention to features by associative learning.

    Science.gov (United States)

    Gozli, Davood G; Moskowitz, Joshua B; Pratt, Jay

    2014-11-01

    Expecting a particular stimulus can facilitate processing of that stimulus over others, but what is the fate of other stimuli that are known to co-occur with the expected stimulus? This study examined the impact of learned association on feature-based attention. The findings show that the effectiveness of an uninformative color transient in orienting attention can change by learned associations between colors and the expected target shape. In an initial acquisition phase, participants learned two distinct sequences of stimulus-response-outcome, where stimuli were defined by shape ('S' vs. 'H'), responses were localized key-presses (left vs. right), and outcomes were colors (red vs. green). Next, in a test phase, while expecting a target shape (80% probable), participants showed reliable attentional orienting to the color transient associated with the target shape, and showed no attentional orienting with the color associated with the alternative target shape. This bias seemed to be driven by learned association between shapes and colors, and not modulated by the response. In addition, the bias seemed to depend on observing target-color conjunctions, since encountering the two features disjunctively (without spatiotemporal overlap) did not replicate the findings. We conclude that associative learning - likely mediated by mechanisms underlying visual object representation - can extend the impact of goal-driven attention to features associated with a target stimulus. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Using reinforcement learning to provide stable brain-machine interface control despite neural input reorganization.

    Science.gov (United States)

    Pohlmeyer, Eric A; Mahmoudi, Babak; Geng, Shijia; Prins, Noeline W; Sanchez, Justin C

    2014-01-01

    Brain-machine interface (BMI) systems give users direct neural control of robotic, communication, or functional electrical stimulation systems. As BMI systems begin transitioning from laboratory settings into activities of daily living, an important goal is to develop neural decoding algorithms that can be calibrated with a minimal burden on the user, provide stable control for long periods of time, and can be responsive to fluctuations in the decoder's neural input space (e.g. neurons appearing or being lost amongst electrode recordings). These are significant challenges for static neural decoding algorithms that assume stationary input/output relationships. Here we use an actor-critic reinforcement learning architecture to provide an adaptive BMI controller that can successfully adapt to dramatic neural reorganizations, can maintain its performance over long time periods, and which does not require the user to produce specific kinetic or kinematic activities to calibrate the BMI. Two marmoset monkeys used the Reinforcement Learning BMI (RLBMI) to successfully control a robotic arm during a two-target reaching task. The RLBMI was initialized using random initial conditions, and it quickly learned to control the robot from brain states using only a binary evaluative feedback regarding whether previously chosen robot actions were good or bad. The RLBMI was able to maintain control over the system throughout sessions spanning multiple weeks. Furthermore, the RLBMI was able to quickly adapt and maintain control of the robot despite dramatic perturbations to the neural inputs, including a series of tests in which the neuron input space was deliberately halved or doubled.

  12. Using reinforcement learning to provide stable brain-machine interface control despite neural input reorganization.

    Directory of Open Access Journals (Sweden)

    Eric A Pohlmeyer

    Full Text Available Brain-machine interface (BMI systems give users direct neural control of robotic, communication, or functional electrical stimulation systems. As BMI systems begin transitioning from laboratory settings into activities of daily living, an important goal is to develop neural decoding algorithms that can be calibrated with a minimal burden on the user, provide stable control for long periods of time, and can be responsive to fluctuations in the decoder's neural input space (e.g. neurons appearing or being lost amongst electrode recordings. These are significant challenges for static neural decoding algorithms that assume stationary input/output relationships. Here we use an actor-critic reinforcement learning architecture to provide an adaptive BMI controller that can successfully adapt to dramatic neural reorganizations, can maintain its performance over long time periods, and which does not require the user to produce specific kinetic or kinematic activities to calibrate the BMI. Two marmoset monkeys used the Reinforcement Learning BMI (RLBMI to successfully control a robotic arm during a two-target reaching task. The RLBMI was initialized using random initial conditions, and it quickly learned to control the robot from brain states using only a binary evaluative feedback regarding whether previously chosen robot actions were good or bad. The RLBMI was able to maintain control over the system throughout sessions spanning multiple weeks. Furthermore, the RLBMI was able to quickly adapt and maintain control of the robot despite dramatic perturbations to the neural inputs, including a series of tests in which the neuron input space was deliberately halved or doubled.

  13. Warm Parenting Associated with Decreasing or Stable Child BMI during Treatment.

    Science.gov (United States)

    Rhee, Kyung E; Jelalian, Elissa; Boutelle, Kerri; Dickstein, Susan; Seifer, Ronald; Wing, Rena

    2016-04-01

    While authoritative parenting, which includes high levels of warmth and behavioral control, has been associated with lower risk of obesity, little is known about how general parenting impacts child weight loss during treatment. Our goal was to examine the relationship between several general parenting dimensions and 'decreasing /stable' child BMI during a 16-week family-based behavioral weight control program. Forty-four overweight parent-child dyads (child age 8 to 12 years) enrolled in the program. Families were videotaped at baseline eating dinner in their home. Using the General Parenting Observational Scale (GPOS), meals were coded for several general parenting dimensions. Primary outcome was percent of children whose BMI 'decreased or stayed the same.' Multivariable logistic regression was used to determine the relationship between general parenting and decreasing/stable child BMI. Forty families (91%) completed the program. Children had a mean BMI change of -0.40 (SD 1.57), which corresponds to a -0.15 (SD 0.20) change in BMI z-score (BMI-Z); 75% of children had decreasing/stable BMI. In the unadjusted models, lower parent BMI, higher parent education, and higher levels of parental warmth were significantly associated with decreasing/stable child BMI. In the multivariable model, only higher level of warmth was associated with increased odds of decreasing/stable child BMI (OR = 1.28; 95% CI, 1.01, 1.62). Baseline parental warmth may influence a child's ability to lower/maintain BMI during a standard family-based behavioral weight control program. Efforts to increase parent displays of warmth and emotional support towards their overweight child may help to increase the likelihood of treatment success.

  14. Fractional flow reserve is not associated with inflammatory markers in patients with stable coronary artery disease.

    Directory of Open Access Journals (Sweden)

    Jan-Willem E M Sels

    Full Text Available BACKGROUND: Atherosclerosis is an inflammatory condition and increased blood levels of inflammatory biomarkers have been observed in acute coronary syndromes. In addition, high expression of inflammatory markers is associated with worse prognosis of coronary artery disease. The presence and extent of inducible ischemia in patients with stable angina has previously been shown to have strong prognostic value. We hypothesized that evidence of inducible myocardial ischemia by local lesions, as measured by fractional flow reserve (FFR, is associated with increased levels of blood based inflammatory biomarkers. METHODS: Whole blood samples of 89 patients with stable angina pectoris and 16 healthy controls were analyzed. The patients with stable angina pectoris underwent coronary angiography and FFR of all coronary lesions. We analyzed plasma levels of cytokines IL-6, IL-8 and TNF-α and membrane expression of Toll-like receptor 2 and 4, CD11b, CD62L and CD14 on monocytes and granulocytes as markers of inflammation. Furthermore, we quantified the severity of hemodynamically significant coronary artery disease by calculating Functional Syntax Score (FSS, an extension of the Syntax Score. RESULTS: For the majority of biomarkers, we observed lower levels in the healthy control group compared with patients with stable angina who underwent coronary catheterization. We found no difference for any of the selected biomarkers between patients with a positive FFR (≤ 0.75 and negative FFR (>0.80. We observed no relationship between the investigated biomarkers and FSS. CONCLUSION: The presence of local atherosclerotic lesions that result in inducible myocardial ischemia as measured by FFR in patients with stable coronary artery disease is not associated with increased plasma levels of IL-6, IL-8 and TNF-α or increased expression of TLR2 and TLR4, CD11b, CD62L and CD14 on circulating leukocytes.

  15. Stable producer cell lines for adeno-associated virus (AAV) assembly.

    Science.gov (United States)

    Chadeuf, Gilliane; Salvetti, Anna

    2010-10-01

    Stable producer cell lines containing both the rep and cap genes and recombinant adeno-associated virus (rAAV) vectors can be infected with a helper virus to provide reliable and efficient production of rAAV stocks. However, the development of these cell lines is time-consuming. The procedure described here is therefore recommended only for studies requiring the production of high amounts of rAAV, such as preclinical studies performed in large animals.

  16. Grounding cognitive control in associative learning.

    Science.gov (United States)

    Abrahamse, Elger; Braem, Senne; Notebaert, Wim; Verguts, Tom

    2016-07-01

    Cognitive control covers a broad range of cognitive functions, but its research and theories typically remain tied to a single domain. Here we outline and review an associative learning perspective on cognitive control in which control emerges from associative networks containing perceptual, motor, and goal representations. Our review identifies 3 trending research themes that are shared between the domains of conflict adaptation, task switching, response inhibition, and attentional control: Cognitive control is context-specific, can operate in the absence of awareness, and is modulated by reward. As these research themes can be envisaged as key characteristics of learning, we propose that their joint emergence across domains is not coincidental but rather reflects a (latent) growth of interest in learning-based control. Associative learning has the potential for providing broad-scaled integration to cognitive control theory, and offers a promising avenue for understanding cognitive control as a self-regulating system without postulating an ill-defined set of homunculi. We discuss novel predictions, theoretical implications, and immediate challenges that accompany an associative learning perspective on cognitive control. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  17. Evolution of associative learning in chemical networks.

    Directory of Open Access Journals (Sweden)

    Simon McGregor

    Full Text Available Organisms that can learn about their environment and modify their behaviour appropriately during their lifetime are more likely to survive and reproduce than organisms that do not. While associative learning - the ability to detect correlated features of the environment - has been studied extensively in nervous systems, where the underlying mechanisms are reasonably well understood, mechanisms within single cells that could allow associative learning have received little attention. Here, using in silico evolution of chemical networks, we show that there exists a diversity of remarkably simple and plausible chemical solutions to the associative learning problem, the simplest of which uses only one core chemical reaction. We then asked to what extent a linear combination of chemical concentrations in the network could approximate the ideal Bayesian posterior of an environment given the stimulus history so far? This Bayesian analysis revealed the 'memory traces' of the chemical network. The implication of this paper is that there is little reason to believe that a lack of suitable phenotypic variation would prevent associative learning from evolving in cell signalling, metabolic, gene regulatory, or a mixture of these networks in cells.

  18. Neuroimaging of Fear-Associated Learning

    Science.gov (United States)

    Greco, John A; Liberzon, Israel

    2016-01-01

    Fear conditioning has been commonly used as a model of emotional learning in animals and, with the introduction of functional neuroimaging techniques, has proven useful in establishing the neurocircuitry of emotional learning in humans. Studies of fear acquisition suggest that regions such as amygdala, insula, anterior cingulate cortex, and hippocampus play an important role in acquisition of fear, whereas studies of fear extinction suggest that the amygdala is also crucial for safety learning. Extinction retention testing points to the ventromedial prefrontal cortex as an essential region in the recall of the safety trace, and explicit learning of fear and safety associations recruits additional cortical and subcortical regions. Importantly, many of these findings have implications in our understanding of the pathophysiology of psychiatric disease. Recent studies using clinical populations have lent insight into the changes in regional activity in specific disorders, and treatment studies have shown how pharmaceutical and other therapeutic interventions modulate brain activation during emotional learning. Finally, research investigating individual differences in neurotransmitter receptor genotypes has highlighted the contribution of these systems in fear-associated learning. PMID:26294108

  19. A Combined Stable Isotope And Machine Learning Approach To Quantify And Classify Of Nitrate Pollution Sources

    Science.gov (United States)

    Boeckx, P. F.; Xue, D.; De Baets, B.

    2011-12-01

    Stable isotope analyses of NO3- (δ15N and δ18O) are widely used to determine the sources of nitrate pollution in water. The objective of our study was (1) to quantify NO3- sources in surface water and to classify surface waters in NO3- pollution classes via a combined stable isotope and machine learning approach; and (2) to assess a decision tree model with physicochemical data for retrieving the latter classification. A logical approach has been followed: (1) 2-year monthly sampling of 30 sampling points from different river basins in Belgium, which were classified into 5 different NO3- pollution classes using experts knowledge (Agriculture (A), Agriculture with groundwater compensation (AGC), Combination of agriculture and horticulture (AH), Greenhouses in an agricultural area (G) and Households (H)); (2) estimating proportional NO3- source contribution per NO3- pollution class by applying a Bayesian isotopic mixing model (SIAR) for measured isotopic data of NO3-; (3) re-classifying the 30 sampling points into NO3- pollution classes via a k-means clustering of the SIAR outputs; and (4) building a decision tree model using physicochemical data to retrieve expert knowledge and k-means clustering classification. SIAR successfully estimated proportional contribution ranges of five potential NO3- sources: NO3- in precipitation, NO3- in fertilizer, NH4+ in fertilizer and precipitation, manure and sewage and soil N. For classes A, AGC, AH and H in winter manure and sewage were major (40 - 60%), NO3- in precipitation minor (pollution classes were optimal for both winter and summer. Thus the 30 sampling points were divided into four classes: classes A, class AGC, class G, and class H (class AH was not retained). Finally, a decision tree model built on physicochemical data using expert classification labels or k-means clustering labels could retrieve ca. 70% of the nitrate pollution classes in both cases. The later suggests that physicochemical data could be applied to

  20. Awake, Offline Processing during Associative Learning.

    Science.gov (United States)

    Bursley, James K; Nestor, Adrian; Tarr, Michael J; Creswell, J David

    2016-01-01

    Offline processing has been shown to strengthen memory traces and enhance learning in the absence of conscious rehearsal or awareness. Here we evaluate whether a brief, two-minute offline processing period can boost associative learning and test a memory reactivation account for these offline processing effects. After encoding paired associates, subjects either completed a distractor task for two minutes or were immediately tested for memory of the pairs in a counterbalanced, within-subjects functional magnetic resonance imaging study. Results showed that brief, awake, offline processing improves memory for associate pairs. Moreover, multi-voxel pattern analysis of the neuroimaging data suggested reactivation of encoded memory representations in dorsolateral prefrontal cortex during offline processing. These results signify the first demonstration of awake, active, offline enhancement of associative memory and suggest that such enhancement is accompanied by the offline reactivation of encoded memory representations.

  1. Awake, Offline Processing during Associative Learning.

    Directory of Open Access Journals (Sweden)

    James K Bursley

    Full Text Available Offline processing has been shown to strengthen memory traces and enhance learning in the absence of conscious rehearsal or awareness. Here we evaluate whether a brief, two-minute offline processing period can boost associative learning and test a memory reactivation account for these offline processing effects. After encoding paired associates, subjects either completed a distractor task for two minutes or were immediately tested for memory of the pairs in a counterbalanced, within-subjects functional magnetic resonance imaging study. Results showed that brief, awake, offline processing improves memory for associate pairs. Moreover, multi-voxel pattern analysis of the neuroimaging data suggested reactivation of encoded memory representations in dorsolateral prefrontal cortex during offline processing. These results signify the first demonstration of awake, active, offline enhancement of associative memory and suggest that such enhancement is accompanied by the offline reactivation of encoded memory representations.

  2. Ontology Learning - Suggesting Associations from Text

    OpenAIRE

    Kvarv, Gøran Sveia

    2007-01-01

    In many applications, large-scale ontologies have to be constructed and maintained. A manual construction of an ontology is a time consuming and resource demanding process, often involving some domain experts. It would therefore be beneficial to support this process with tools that automates the construction of an ontology. This master thesis has examined the use of association rules for suggesting associations between words in text. In ontology learning, concepts are often extracted from d...

  3. A model of olfactory associative learning

    Science.gov (United States)

    Tavoni, Gaia; Balasubramanian, Vijay

    We propose a mechanism, rooted in the known anatomy and physiology of the vertebrate olfactory system, by which presentations of rewarded and unrewarded odors lead to formation of odor-valence associations between piriform cortex (PC) and anterior olfactory nucleus (AON) which, in concert with neuromodulators release in the bulb, entrains a direct feedback from the AON representation of valence to a group of mitral cells (MCs). The model makes several predictions concerning MC activity during and after associative learning: (a) AON feedback produces synchronous divergent responses in a localized subset of MCs; (b) such divergence propagates to other MCs by lateral inhibition; (c) after learning, MC responses reconverge; (d) recall of the newly formed associations in the PC increases feedback inhibition in the MCs. These predictions have been confirmed in disparate experiments which we now explain in a unified framework. For cortex, our model further predicts that the response divergence developed during learning reshapes odor representations in the PC, with the effects of (a) decorrelating PC representations of odors with different valences, (b) increasing the size and reliability of those representations, and enabling recall correction and redundancy reduction after learning. Simons Foundation for Mathematical Modeling of Living Systems.

  4. Visual associative learning in wood ants.

    Science.gov (United States)

    Fernandes, A Sofia D; Buckley, Christopher L; Niven, Jeremy E

    2018-02-07

    Wood ants are a model system for studying visual learning and navigation. They can forage for food and navigate to their nests effectively by forming memories of visual features in their surrounding environment. Previous studies of freely behaving ants have revealed many of the behavioural strategies and environmental features necessary for successful navigation. However, little is known about the exact visual properties of the environment that animals learn or the neural mechanisms that allow them to achieve this. As a first step towards addressing this, we developed a classical conditioning paradigm for visual learning in harnessed wood ants that allows us to control precisely the learned visual cues. In this paradigm, ants are fixed and presented with a visual cue paired with an appetitive sugar reward. Using this paradigm, we found that visual cues learnt by wood ants through Pavlovian conditioning are retained for at least 1 h. Furthermore, we found that memory retention is dependent upon the ants' performance during training. Our study provides the first evidence that wood ants can form visual associative memories when restrained. This classical conditioning paradigm has the potential to permit detailed analysis of the dynamics of memory formation and retention, and the neural basis of learning in wood ants. © 2018. Published by The Company of Biologists Ltd.

  5. COMPARISON BETAXOLOL AND METOPROLOL TARTRATE THERAPIES IN PATIENTS WITH ARTERIAL HYPERTENSION ASSOCIATED WITH STABLE ANGINA

    Directory of Open Access Journals (Sweden)

    A. A. Anderzhanova

    2016-01-01

    Full Text Available Aim. To compare antihypertensive, antianginal and antiischemic efficacy of β1-selective adrenoblockers (betaxolol and metoprolol tartrate in patients with arterial hypertension (HT of 1-2 degree associated with stable angina class II.Material and methods. 100 patients (aged 23-66 y.o. with HT associated with stable angina or without angina were involved in the study. Patients were randomized into 2 groups (G1 and G2. G1 patients were treated with betaxolol, and G2 patients – with metoprolol tartrate. Ambulatory BP and electrocardiogram monitoring, exercise stress-test, echocardiography, evaluating of respiratory function, blood analysis was performed initially and in 30 and 90 days of treatment.Results. Target BP level was reached in 44 (88% patients treated with betaxolol (average daily dose 10±4 mg. 34 patients of G1 took 10 mg daily. Target BP level was reached in 41 (82% patients treated with metoprolol tartrate (average daily dose 150±27 mg. 30 patients of G2 took 150 mg daily. Exercise tolerance increased and a number of ischemic ST segment depressions reduced significantly in both groups. There were no significant differences in antihypertensive, antianginal, and antiischemic efficacy between groups.Conclusion. Betaxolol advantage is an ability to maintain target BP level more than 24 hours. A possibility to take betaxolol once a day raises patient’s compliance with therapy.

  6. Stable isotopes reveal rail-associated behavior in a threatened carnivore.

    Science.gov (United States)

    Hopkins, John B; Whittington, Jesse; Clevenger, Anthony P; Sawaya, Michael A; St Clair, Colleen Cassady

    2014-01-01

    Human-wildlife conflict is a leading cause of adult mortality for large carnivores worldwide. Train collision is the primary cause of mortality for threatened grizzly bears (Ursus arctos) in Banff National Park. We investigated the use of stable isotope analysis as a tool for identifying bears that use the railway in Banff. Rail-associated bears had higher δ(15)N and δ(34)S values than bears sampled away from the rail, but similar δ(13)C values. Because elevated δ(15)N values are indicative of higher animal protein consumption, rail-associated bears likely preyed on ungulates that foraged along the rail or scavenged on train-killed animals. The higher δ(34)S values in bear hair could have resulted from bears consuming sulfur pellets spilled on the rail or through the uptake of sulfur in the plants bears or animals consumed. Similar δ(13)C values suggest that the two types of bears had generally similar plant-based diets. Results from this study suggest that stable isotopes analysis could be used as a non-invasive, affordable, and efficient technique to identify and monitor bears that forage on the railway in Banff and potentially other transportation corridors worldwide.

  7. The association between self-esteem and happiness differs in relationally mobile vs. stable contexts

    Directory of Open Access Journals (Sweden)

    Kosuke eSato

    2014-10-01

    Full Text Available Does a change in the nature of surrounding social context affect the strength of association between self-esteem and happiness? This paper aims to answer this question from a socio-ecological perspective, focusing on the role of relational mobility. Recent research has shown that this association is stronger in societies that are higher in relational mobility, where there is a greater freedom of choice in interpersonal relationships and group memberships. In this study, we tested if this hypothesis could be applied to situational differences within the same physical setting. Using a quasi-experimental design, we tested if the association between self-esteem and happiness was stronger for first-year students at a Japanese university who had just entered the college and thus were in a relatively higher mobility context, than the second year students at the same university whose relationships tended to be more stable and long-standing. The results showed, as predicted, that the association between self-esteem and happiness was stronger for the first-year students than for the second-year students. Implications for the theory and research on social change are discussed.

  8. The association between self-esteem and happiness differs in relationally mobile vs. stable interpersonal contexts.

    Science.gov (United States)

    Sato, Kosuke; Yuki, Masaki

    2014-01-01

    Does a change in the nature of surrounding social context affect the strength of association between self-esteem and happiness? This paper aims to answer this question from a socio-ecological perspective, focusing on the role of relational mobility. Recent research has shown that this association is stronger in societies that are higher in relational mobility, where there is a greater freedom of choice in interpersonal relationships and group memberships. In this study, we tested if this hypothesis could be applied to situational differences within the same physical setting. Using a quasi-experimental design, we tested if the association between self-esteem and happiness was stronger for first-year students at a Japanese university who had just entered the college and thus were in a relatively higher mobility context, than the second-year students at the same university whose relationships tended to be more stable and long-standing. The results showed, as predicted, that the association between self-esteem and happiness was stronger for the first-year students than for the second-year students. Implications for the theory and research on social change are discussed.

  9. Learned reward association improves visual working memory.

    Science.gov (United States)

    Gong, Mengyuan; Li, Sheng

    2014-04-01

    Statistical regularities in the natural environment play a central role in adaptive behavior. Among other regularities, reward association is potentially the most prominent factor that influences our daily life. Recent studies have suggested that pre-established reward association yields strong influence on the spatial allocation of attention. Here we show that reward association can also improve visual working memory (VWM) performance when the reward-associated feature is task-irrelevant. We established the reward association during a visual search training session, and investigated the representation of reward-associated features in VWM by the application of a change detection task before and after the training. The results showed that the improvement in VWM was significantly greater for items in the color associated with high reward than for those in low reward-associated or nonrewarded colors. In particular, the results from control experiments demonstrate that the observed reward effect in VWM could not be sufficiently accounted for by attentional capture toward the high reward-associated item. This was further confirmed when the effect of attentional capture was minimized by presenting the items in the sample and test displays of the change detection task with the same color. The results showed significantly larger improvement in VWM performance when the items in a display were in the high reward-associated color than those in the low reward-associated or nonrewarded colors. Our findings suggest that, apart from inducing space-based attentional capture, the learned reward association could also facilitate the perceptual representation of high reward-associated items through feature-based attentional modulation.

  10. Trade-off between learning and exploitation: the Pareto-optimal versus evolutionarily stable learning schedule in cumulative cultural evolution.

    Science.gov (United States)

    Wakano, Joe Yuichiro; Miura, Chiaki

    2014-02-01

    Inheritance of culture is achieved by social learning and improvement is achieved by individual learning. To realize cumulative cultural evolution, social and individual learning should be performed in this order in one's life. However, it is not clear whether such a learning schedule can evolve by the maximization of individual fitness. Here we study optimal allocation of lifetime to learning and exploitation in a two-stage life history model under a constant environment. We show that the learning schedule by which high cultural level is achieved through cumulative cultural evolution is unlikely to evolve as a result of the maximization of individual fitness, if there exists a trade-off between the time spent in learning and the time spent in exploiting the knowledge that has been learned in earlier stages of one's life. Collapse of a fully developed culture is predicted by a game-theoretical analysis where individuals behave selfishly, e.g., less learning and more exploiting. The present study suggests that such factors as group selection, the ability of learning-while-working ("on the job training"), or environmental fluctuation might be important in the realization of rapid and cumulative cultural evolution that is observed in humans. Copyright © 2013 Elsevier Inc. All rights reserved.

  11. Accounting for Individual Differences in Human Associative Learning.

    Directory of Open Access Journals (Sweden)

    Nicola C Byrom

    2013-09-01

    Full Text Available Associative learning has provided fundamental insights to understanding psychopathology. However, psychopathology occurs along a continuum and as such, identification of disruptions in processes of associative learning associated with aspects of psychopathology illustrates a general flexibility in human associative learning. A handful of studies have looked specifically at individual differences in human associative learning, but while much work has concentrated on accounting for flexibility in learning caused by external factors, there has been limited work considering how to model the influence of dispositional factors. This review looks at the range of individual differences in human associative learning that have been explored and the attempts to account for, and model, this flexibility. To fully understand human associative learning, further research needs to attend to the causes of variation in human learning.

  12. Stable intergenerational associations of childhood overweight during the development of the obesity epidemic

    DEFF Research Database (Denmark)

    Ajslev, Teresa A; Ängquist, Lars; Silventoinen, Karri

    2015-01-01

    of children born to parents with and without childhood overweight. METHODS: The study population was from the Copenhagen School Health Records Register, which includes age- and sex-specific body mass index (BMI; kg/m(2) ) of children. This study used BMI values from 7-year-old children born 1952-1989 and from....... RESULTS: Stable levels in parent-child overweight associations were observed across child BMI groups born to parents with and without childhood overweight. A slight upward odds ratio trend was observed across time in children born to two overweight parents at age 13, but not at age 7 years. CONCLUSIONS......: Parent-child resemblance in childhood overweight showed small changes during the development of the obesity epidemic, suggesting that the obesogenic environment inducing the epidemic in Denmark influenced children irrespective of their familial predisposition....

  13. Learning with Correntropy-induced Losses for Regression with Mixture of Symmetric Stable Noise

    OpenAIRE

    Feng, Yunlong; Ying, Yiming

    2018-01-01

    In recent years, correntropy and its applications in machine learning have been drawing continuous attention owing to its merits in dealing with non-Gaussian noise and outliers. However, theoretical understanding of correntropy, especially in the statistical learning context, is still limited. In this study, within the statistical learning framework, we investigate correntropy based regression in the presence of non-Gaussian noise or outliers. To this purpose, we first introduce mixture of sy...

  14. The acquisition of simple associations as observed in color-word contingency learning.

    Science.gov (United States)

    Lin, Olivia Y-H; MacLeod, Colin M

    2018-01-01

    Three experiments investigated the learning of simple associations in a color-word contingency task. Participants responded manually to the print colors of 3 words, with each word associated strongly to 1 of the 3 colors and weakly to the other 2 colors. Despite the words being irrelevant, response times to high-contingency stimuli and to low-contingency stimuli quickly diverged. This high-low difference remained quite constant over successive blocks of trials, evidence of stable contingency learning. Inclusion of a baseline condition-an item having no color-word contingency-permitted separation of the contingency learning effect into 2 components: a cost due to low contingency and a benefit due to high contingency. Both cost and benefit were quick to acquire, quick to extinguish, and quick to reacquire. The color-word contingency task provides a simple way to directly study the learning of associations. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  15. Exploration of Learning Strategies Associated With Aha Learning Moments.

    Science.gov (United States)

    Pilcher, Jobeth W

    2016-01-01

    Educators recognize aha moments as powerful aspects of learning. Yet limited research has been performed regarding how to promote these learning moments. This article describes an exploratory study of aha learning moments as experienced and described by participants. Findings showed use of visuals, scenarios, storytelling, Socratic questions, and expert explanation led to aha learning moments. The findings provide guidance regarding the types of learning strategies that can be used to promote aha moments.

  16. Cohesin rings devoid of Scc3 and Pds5 maintain their stable association with the DNA.

    Directory of Open Access Journals (Sweden)

    Irina Kulemzina

    Full Text Available Cohesin is a protein complex that forms a ring around sister chromatids thus holding them together. The ring is composed of three proteins: Smc1, Smc3 and Scc1. The roles of three additional proteins that associate with the ring, Scc3, Pds5 and Wpl1, are not well understood. It has been proposed that these three factors form a complex that stabilizes the ring and prevents it from opening. This activity promotes sister chromatid cohesion but at the same time poses an obstacle for the initial entrapment of sister DNAs. This hindrance to cohesion establishment is overcome during DNA replication via acetylation of the Smc3 subunit by the Eco1 acetyltransferase. However, the full mechanistic consequences of Smc3 acetylation remain unknown. In the current work, we test the requirement of Scc3 and Pds5 for the stable association of cohesin with DNA. We investigated the consequences of Scc3 and Pds5 depletion in vivo using degron tagging in budding yeast. The previously described DHFR-based N-terminal degron as well as a novel Eco1-derived C-terminal degron were employed in our study. Scc3 and Pds5 associate with cohesin complexes independently of each other and require the Scc1 "core" subunit for their association with chromosomes. Contrary to previous data for Scc1 downregulation, depletion of either Scc3 or Pds5 had a strong effect on sister chromatid cohesion but not on cohesin binding to DNA. Quantity, stability and genome-wide distribution of cohesin complexes remained mostly unchanged after the depletion of Scc3 and Pds5. Our findings are inconsistent with a previously proposed model that Scc3 and Pds5 are cohesin maintenance factors required for cohesin ring stability or for maintaining its association with DNA. We propose that Scc3 and Pds5 specifically function during cohesion establishment in S phase.

  17. A Neural Circuit for Acoustic Navigation combining Heterosynaptic and Non-synaptic Plasticity that learns Stable Trajectories

    DEFF Research Database (Denmark)

    Shaikh, Danish; Manoonpong, Poramate

    2017-01-01

    Reactive spatial robot navigation in goal-directed tasks such as phonotaxis requires generating consistent and stable trajectories towards an acoustic target while avoiding obstacles. High-level goal-directed steering behaviour can steer a robot towards the target by mapping sound direction...... information to appropriate wheel velocities. However, low-level obstacle avoidance behaviour based on distance sensors may significantly alter wheel velocities and temporarily direct the robot away from the sound source, creating conflict between the two behaviours. How can such a conflict in reactive...... controllers be resolved in a manner that generates consistent and stable robot trajectories? We propose a neural circuit that minimises this conflict by learning sensorimotor mappings as neuronal transfer functions between the perceived sound direction and wheel velocities of a simulated non-holonomic mobile...

  18. The clinical associate curriculum . the learning theory underpinning ...

    African Journals Online (AJOL)

    Drawing on the theories and practices of authentic learning, self-directed learning, whole-brain learning and collaborative learning, the curriculum has been transformed. The potential of this curriculum extends beyond the formal education part of the programme . into clinical associate practice, healthcare practice and, ...

  19. Using stable isotopes to associate migratory shorebirds with their wintering locations in Argentina

    Science.gov (United States)

    Farmer, A.H.; Abril, M.; Fernandez, M.; Torres, J.; Kester, C.; Bern, C.

    2004-01-01

    We are evaluating the use of stable isotopes to identify the wintering areas of Neotropical migratory shorebirds in Argentina. Our goal is to associate individual birds, captured on the breeding grounds or in migration with specific winter sites, thereby helping to identify distinct areas used by different subpopulations. In January and February 2002 and 2003, we collected flight feathers from shorebirds at 23 wintering sites distributed across seven province s in Argentina (n = 170). Feathers samples were pre- pared and analyzed for δ13C, δ15N, δ34S, δ18O and δD by continuous flow methods. A discriminant function based on deuterium alone was not an accurate predictor of a shorebird’s province of origin, ranging from 8% correct (Santiago del Estero) to 80% correct (San ta Cruz). When other isotopes were included, the prediction accuracy increased substantially (from 56% in Buenos Aires to 100% in Tucumán). The improvement in accuracy was due to C/N, which separated D-depleted sites in the Andes from those in the south, and the inclusion of S separated sites with respect to their distance from the Atlantic. We also were able to correctly discriminate shorebirds from among two closely spaced sites within the province of Tierra del Fuego. These results suggest the feasibility of identifying the origin of a shorebird at a provincial level of accuracy, as well as uniquely identifying birds from some closely spaced sites. There is a high degree of intra- and inter-bird variability, especially in the Pampas region, where there is wide variety of wetland/water conditions. In that important shorebird region, the variability itself may in fact be the “signature.” Future addition of trace elements to the analyses may improve predictions based solely on stable isotopes.

  20. Participatory Common Learning in Groups of Dairy Farmers in Uganda (FFS approach) and Danish Stable Schools

    DEFF Research Database (Denmark)

    Vaarst, Mette

    on a Master Thesis in Health Anthropology and a mini manual to the so-called Stable Schools. Improvements of farming practices should be based on the context of the individual farm and include the goals of the farmer and the farming system. This should be the case in all types of farming systems. Viewing...

  1. Comfort and experience with online learning: trends over nine years and associations with knowledge.

    Science.gov (United States)

    Cook, David A; Thompson, Warren G

    2014-07-01

    Some evidence suggests that attitude toward computer-based instruction is an important determinant of success in online learning. We sought to determine how comfort using computers and perceptions of prior online learning experiences have changed over the past decade, and how these associate with learning outcomes. Each year from 2003-2011 we conducted a prospective trial of online learning. As part of each year's study, we asked medicine residents about their comfort using computers and if their previous experiences with online learning were favorable. We assessed knowledge using a multiple-choice test. We used regression to analyze associations and changes over time. 371 internal medicine and family medicine residents participated. Neither comfort with computers nor perceptions of prior online learning experiences showed a significant change across years (p > 0.61), with mean comfort rating 3.96 (maximum 5 = very comfortable) and mean experience rating 4.42 (maximum 6 = strongly agree [favorable]). Comfort showed no significant association with knowledge scores (p = 0.39) but perceptions of prior experiences did, with a 1.56% rise in knowledge score for a 1-point rise in experience score (p = 0.02). Correlations among comfort, perceptions of prior experiences, and number of prior experiences were all small and not statistically significant. Comfort with computers and perceptions of prior experience with online learning remained stable over nine years. Prior good experiences (but not comfort with computers) demonstrated a modest association with knowledge outcomes, suggesting that prior course satisfaction may influence subsequent learning.

  2. Foraging Strategies of Laysan Albatross Inferred from Stable Isotopes: Implications for Association with Fisheries.

    Directory of Open Access Journals (Sweden)

    Ann E Edwards

    Full Text Available Fatal entanglement in fishing gear is the leading cause of population decline for albatross globally, a consequence of attraction to bait and fishery discards of commercial fishing operations. We investigated foraging strategies of Laysan albatross (Phoebastria immutabilis, as inferred from nitrogen and carbon isotope values of primary feathers, to determine breeding-related, seasonal, and historic factors that may affect the likelihood of association with Alaskan or Hawaiian longline fisheries. Feather samples were collected from live birds monitored for breeding status and breeding success on Midway Atoll in the northwestern Hawaiian Islands, birds salvaged as fisheries-bycatch, and birds added to museum collections before 1924. During the chick-rearing season (sampled April-May, means and variances of stable isotope values of birds with the highest, most consistent reproductive success were distinct from less productive conspecifics and completely different from birds caught in Hawaiian or Alaskan longline fisheries, suggesting birds with higher multi-annual reproductive success were less likely to associate with these fisheries. Contemporary birds with the highest reproductive success had mean values most similar to historic birds. Values of colony-bound, courting prebreeders were similar to active breeders but distinct from prebreeders caught in Alaskan longline fisheries. During the breeding season, δ15N values were highly variable for both contemporary and historic birds. Although some historic birds exhibited extremely low δ15N values unmatched by contemporary birds (< 11.2‰, others had values as high as the highest fishery-associated contemporary birds. During the non-breeding season (sampled July-September, isotopic variability coalesced into a more narrow set of values for both contemporary and historic birds. Our results suggest that foraging strategies of Laysan albatross are a complex function of season, breeding status, and

  3. Acute psychophysiological stress impairs human associative learning.

    Science.gov (United States)

    Ehlers, M R; Todd, R M

    2017-11-01

    Addiction is increasingly discussed asa disorder of associative learning processes, with both operant and classical conditioning contributing to the development of maladaptive habits. Stress has long been known to promote drug taking and relapse and has further been shown to shift behavior from goal-directed actions towards more habitual ones. However, it remains to be investigated how acute stress may influence simple associative learning processes that occur before a habit can be established. In the present study, healthy young adults were exposed to either acute stress or a control condition half an hour before performing simple classical and operant conditioning tasks. Psychophysiological measures confirmed successful stress induction. Results of the operant conditioning task revealed reduced instrumental responding under delayed acute stress that resembled behavioral responses to lower levels of reward. The classical conditioning experiment revealed successful conditioning in both experimental groups; however, explicit knowledge of conditioning as indicated by stimulus ratings differentiated the stress and control groups. These findings suggest that operant and classical conditioning are differentially influenced by the delayed effects of acute stress with important implications for the understanding of how new habitual behaviors are initially established. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Understanding trophic interactions in host-parasite associations using stable isotopes of carbon and nitrogen.

    Science.gov (United States)

    Nachev, Milen; Jochmann, Maik A; Walter, Friederike; Wolbert, J Benjamin; Schulte, S Marcel; Schmidt, Torsten C; Sures, Bernd

    2017-02-17

    Stable isotope analysis of carbon and nitrogen can deliver insights into trophic interactions between organisms. While many studies on free-living organisms are available, the number of those focusing on trophic interactions between hosts and their associated parasites still remains scarce. In some cases information about taxa (e.g. acanthocephalans) is completely missing. Additionally, available data revealed different and occasionally contrasting patterns, depending on the parasite's taxonomic position and its degree of development, which is most probably determined by its feeding strategy (absorption of nutrients through the tegument versus active feeding) and its localization in the host. Using stable isotope analysis of carbon and nitrogen we provided first data on the trophic position of an acanthocephalan species with respect to its fish host. Barbels (Barbus barbus) infected only with adult acanthocephalans Pomphorhynchus laevis as well as fish co-infected with the larval (L4) nematodes Eustrongylides sp. from host body cavity were investigated in order to determine the factors shaping host-parasite trophic interactions. Fish were collected in different seasons, to study also potential isotopic shifts over time, whereas barbels with single infection were obtained in summer and co-infected ones in autumn. Acanthocephalans as absorptive feeders showed lower isotope discrimination values of δ 15 N than the fish host. Results obtained for the acanthocephalans were in line with other parasitic taxa (e.g. cestodes), which exhibit a similar feeding strategy. We assumed that they feed mainly on metabolites, which were reprocessed by the host and are therefore isotopically lighter. In contrast, the nematodes were enriched in the heavier isotope δ 15 N with respect to their host and the acanthocephalans, respectively. As active feeders they feed on tissues and blood in the body cavity of the host and thus showed isotope discrimination patterns resembling those of

  5. Foraging Strategies of Laysan Albatross Inferred from Stable Isotopes: Implications for Association with Fisheries.

    Science.gov (United States)

    Edwards, Ann E; Fitzgerald, Shannon M; Parrish, Julia K; Klavitter, John L; Romano, Marc D

    2015-01-01

    Fatal entanglement in fishing gear is the leading cause of population decline for albatross globally, a consequence of attraction to bait and fishery discards of commercial fishing operations. We investigated foraging strategies of Laysan albatross (Phoebastria immutabilis), as inferred from nitrogen and carbon isotope values of primary feathers, to determine breeding-related, seasonal, and historic factors that may affect the likelihood of association with Alaskan or Hawaiian longline fisheries. Feather samples were collected from live birds monitored for breeding status and breeding success on Midway Atoll in the northwestern Hawaiian Islands, birds salvaged as fisheries-bycatch, and birds added to museum collections before 1924. During the chick-rearing season (sampled April-May), means and variances of stable isotope values of birds with the highest, most consistent reproductive success were distinct from less productive conspecifics and completely different from birds caught in Hawaiian or Alaskan longline fisheries, suggesting birds with higher multi-annual reproductive success were less likely to associate with these fisheries. Contemporary birds with the highest reproductive success had mean values most similar to historic birds. Values of colony-bound, courting prebreeders were similar to active breeders but distinct from prebreeders caught in Alaskan longline fisheries. During the breeding season, δ15N values were highly variable for both contemporary and historic birds. Although some historic birds exhibited extremely low δ15N values unmatched by contemporary birds (isotopic variability coalesced into a more narrow set of values for both contemporary and historic birds. Our results suggest that foraging strategies of Laysan albatross are a complex function of season, breeding status, and multi-annual breeding success, factors that likely affect the probability of association with fisheries.

  6. A Functional Genomic Analysis of NF1-Associated Learning Disabilities

    National Research Council Canada - National Science Library

    Tang, Shao-Jun

    2008-01-01

    Learning disabilities severely deteriorate the life of many NF1 patients. However, the pathogenic process for NF1-associated learning disabilities has not been fully understood and an effective therapy is not available...

  7. A Functional Genomic Analysis of NF1-Associated Learning Disabilities

    National Research Council Canada - National Science Library

    Tang, Shao-Jun

    2006-01-01

    Learning disabilities severely deteriorate the life of many NFI patients. However, the pathogenic process for NFI-associated learning disabilities has not been fully understood and an effective therapy is not available...

  8. A Functional Genomic Analysis of NF1-Associated Learning Disabilities

    National Research Council Canada - National Science Library

    Tang, Shao-Jun

    2007-01-01

    Learning disabilities severely deteriorate the life of many NF1 patients. However, the pathogenic process for NF1-associated learning disabilities has not been fully understood and an effective therapy is not available...

  9. Stable intergenerational associations of childhood overweight during the development of the obesity epidemic.

    Science.gov (United States)

    Ajslev, Teresa A; Ängquist, Lars; Silventoinen, Karri; Baker, Jennifer L; Sørensen, Thorkild I A

    2015-06-01

    The obesity epidemic may have developed as a response to the obesogenic environment among the genetically predisposed. This investigation examined whether the intergenerational resemblances in childhood overweight changed across the development of the obesity epidemic in groups of children born to parents with and without childhood overweight. The study population was from the Copenhagen School Health Records Register, which includes age- and sex-specific body mass index (BMI; kg/m(2) ) of children. This study used BMI values from 7-year-old children born 1952-1989 and from their parents at ages 7 and 13 years. The available number of parent-child pairs ranged from 17,926 through 42,184. The odds ratios of childhood overweight (BMI z-score >90th percentile) were calculated using logistic regression by parental BMI groups (BMI > or ≤90th percentile) and child birth year intervals. Stable levels in parent-child overweight associations were observed across child BMI groups born to parents with and without childhood overweight. A slight upward odds ratio trend was observed across time in children born to two overweight parents at age 13, but not at age 7 years. Parent-child resemblance in childhood overweight showed small changes during the development of the obesity epidemic, suggesting that the obesogenic environment inducing the epidemic in Denmark influenced children irrespective of their familial predisposition. © 2015 The Obesity Society.

  10. Using Stable Carbon and Nitrogen Isotopes of Hair to Teach about Sustainable Agriculture through Active Learning

    Science.gov (United States)

    Cotton, Jennifer M.; Sheldon, Nathan D.

    2013-01-01

    The call for reform of science education is nearly three decades old (National Commission on Excellence in Education, 1983), but the implementation of such education improvements in the form of active learning techniques in large enrollment classes remains difficult. Here we present a class project designed to increase student involvement and…

  11. Heart rate modulation in stable coronary artery disease without clinical heart failure: What we have already learned from SIGNIFY?

    Directory of Open Access Journals (Sweden)

    Gian Piero Perna

    2016-12-01

    In conclusion, heart rate is a marker of risk but is not a risk factor and/or a target of therapy in patients with stable coronary artery disease and preserved ventricular systolic function. Standard doses of ivabradine are indicated for treatment of angina as an alternative or in addition to beta-blockers, but should not be administered in association with CYP3A4 inhibitors or heart rate-lowering calcium-channel blockers.

  12. Chronic stable angina is associated with lower health-related quality of life: evidence from Chinese patients.

    Directory of Open Access Journals (Sweden)

    Jing Wu

    Full Text Available OBJECTIVES: To compare health-related quality of life (HRQoL between patients with stable angina and the general population in China and to examine factors associated with HRQoL among patients with stable angina. METHODS: A cross-sectional HRQoL survey of stable angina patients recruited from 4 hospitals (n = 411 and the general population recruited from 3 Physical Examination Centers (n = 549 was conducted from July to December, 2011 in two large cities, Tianjin and Chengdu. HRQoL was assessed using the EQ-5D, EQ-VAS, and SF-6D instruments. The health status specific to patients with stable angina was assessed using the Seattle Angina Questionnaire (SAQ. Information on socio-demographic, clinical, and lifestyle factors were also collected. Nested regressions were performed to explore how these factors were associated with HRQoL in patients with stable angina. RESULTS: Compared with the general population (44.2 ± 10 years, 49.9% females, stable angina patients (68.1 ± 12 years, 50.4% females had significantly lower HRQoL scores in EQ-5D utility index (0.75 ± 0.19 vs. 0.90 ± 0.20, p<0.05, SF-6D utility index (0.68 ± 0.12 vs. 0.85 ± 0.11, p<0.05, and EQ-VAS (71.2 ± 12.3 vs. 83.9 ± 10.9, p<0.05. The differences remained (-0.05 for EQ-5D, -9.27 for EQ-VAS and -0.13 for SF-6D after controlling for socio-economic characteristics. SAQ scores showed that stable angina patients experienced impaired disease-specific health status, especially in angina stability (40.5 ± 34.6. Nested regressions indicated stable angina-specific health status explained most of the variation in HRQoL, among which disease perception, physical limitation, and angina stability were the strongest predictors. More physical exercise and better sleep were positively related with HRQoL. CONCLUSIONS: Compared to the general population, stable angina patients were associated with lower HRQoL and lower health utility scores, which were largely impacted by clinical symptoms

  13. Association of small dense LDL serum levels and circulating monocyte subsets in stable coronary artery disease.

    Directory of Open Access Journals (Sweden)

    Konstantin A Krychtiuk

    Full Text Available Atherosclerosis is considered to be an inflammatory disease in which monocytes and monocyte-derived macrophages play a key role. Circulating monocytes can be divided into three distinct subtypes, namely in classical monocytes (CM; CD14++CD16-, intermediate monocytes (IM; CD14++CD16+ and non-classical monocytes (NCM; CD14+CD16++. Low density lipoprotein particles are heterogeneous in size and density, with small, dense LDL (sdLDL crucially implicated in atherogenesis. The aim of this study was to examine whether monocyte subsets are associated with sdLDL serum levels.We included 90 patients with angiographically documented stable coronary artery disease and determined monocyte subtypes by flow cytometry. sdLDL was measured by an electrophoresis method on polyacrylamide gel.Patients with sdLDL levels in the highest tertile (sdLDL≥4mg/dL;T3 showed the highest levels of pro-inflammatory NCM (15.2±7% vs. 11.4±6% and 10.9±4%, respectively; p<0.01 when compared with patients in the middle (sdLDL=2-3mg/dL;T2 and lowest tertile (sdLDL=0-1mg/dL;T1. Furthermore, patients in the highest sdLDL tertile showed lower CM levels than patients in the middle and lowest tertile (79.2±8% vs. 83.9±7% and 82.7±5%; p<0.01 for T3 vs. T2+T1. Levels of IM were not related to sdLDL levels (5.6±4% vs. 4.6±3% vs. 6.4±3% for T3, T2 and T1, respectively. In contrast to monocyte subset distribution, levels of circulating pro- and anti-inflammatory markers were not associated with sdLDL levels.The atherogenic lipoprotein fraction sdLDL is associated with an increase of NCM and a decrease of CM. This could be a new link between lipid metabolism dysregulation, innate immunity and atherosclerosis.

  14. Learning in rich networks involves both positive and negative associations.

    Science.gov (United States)

    Roembke, Tanja C; Wasserman, Edward A; McMurray, Bob

    2016-08-01

    Adaptive behaviors are believed to be shaped by both positive (the strengthening of correct associations) and negative (the pruning of incorrect associations or the building of inhibitory associations) forms of associative learning. However, there has been little direct documentation of how these basic processes participate in the learning of rich associative networks that support cognitive behaviors like categorization. Although negative associative learning is an important component of theories of development, it is not clear whether it involves acquiring specific (experience-dependent) content or represents a more general aspect of (experience-expectant) development. The authors thus trained pigeons on a complex many-to-many learning paradigm previously established as an analog to human word learning. Pigeons learned to map 16 objects onto 16 distinct report tokens; the authors manipulated the amount of negative associative learning that could occur by restricting which tokens were available as incorrect options. In testing, accuracy was lower on trials with foils that had not been presented with a target than on trials with previously experienced foils. Moreover, when the correct token was withheld, pigeons preferred foils novel to the target object over previously experienced foils. A second experiment replicated these results and further found that these effects only emerged after some positive associations had been acquired. Findings indicate that the learning of rich associative networks does not depend solely on positive associative learning, but also on negative associative learning; this conclusion has important implications for basic learning theories in both animals and humans, as well as for theories of development. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  15. Associative learning and the control of human dietary behavior.

    Science.gov (United States)

    Brunstrom, Jeffrey M

    2007-07-01

    Most of our food likes and disliked are learned. Relevant forms of associative learning have been identified in animals. However, observations of the same associative processes are relatively scarce in humans. The first section of this paper outlines reasons why this might be the case. Emphasis is placed on recent research exploring individual differences and the importance or otherwise of hunger and contingency awareness. The second section briefly considers the effect of learning on meal size, and the author revisits the question of how learned associations might come to influence energy intake in humans.

  16. The development of associate learning in school age children.

    Directory of Open Access Journals (Sweden)

    Brian T Harel

    Full Text Available Associate learning is fundamental to the acquisition of knowledge and plays a critical role in the everyday functioning of the developing child, though the developmental course is still unclear. This study investigated the development of visual associate learning in 125 school age children using the Continuous Paired Associate Learning task. As hypothesized, younger children made more errors than older children across all memory loads and evidenced decreased learning efficiency as memory load increased. Results suggest that age-related differences in performance largely reflect continued development of executive function in the context of relatively developed memory processes.

  17. Stable Learning of Functional Maps in Self-Organizing Spiking Neural Networks with Continuous Synaptic Plasticity

    Directory of Open Access Journals (Sweden)

    Narayan eSrinivasa

    2013-02-01

    Full Text Available This study describes a spiking model that self-organizes for stable formation and maintenance of orientation and ocular dominance maps in the visual cortex (V1. This self-organization process simulates three development phases: an early experience-independent phase, a late experience-independent phase and a subsequent refinement phase during which experience acts to shape the map properties. The ocular dominance maps that emerge accommodate the two sets of monocular inputs that arise from the lateral geniculate nucleus (LGN to layer 4 of V1. The orientation selectivity maps that emerge feature well-developed iso-orientation domains and fractures. During the last two phases of development the orientation preferences at some locations appear to rotate continuously through +/- 180 along circular paths and referred to as pinwheel-like patterns but without any corresponding point discontinuities in the orientation gradient maps. The formation of these functional maps is driven by balanced excitatory and inhibitory currents that are established via synaptic plasticity based on spike timing for both excitatory and inhibitory synapses. The stability and maintenance of the formed maps with continuous synaptic plasticity is enabled by homeostasis caused by inhibitory plasticity. However, a prolonged exposure to repeated stimuli does alter the formed maps over time due to plasticity. The results from this study suggest that continuous synaptic plasticity in both excitatory neurons and interneurons could play a critical role in the formation, stability, and maintenance of functional maps in the cortex.

  18. Stable learning of functional maps in self-organizing spiking neural networks with continuous synaptic plasticity.

    Science.gov (United States)

    Srinivasa, Narayan; Jiang, Qin

    2013-01-01

    This study describes a spiking model that self-organizes for stable formation and maintenance of orientation and ocular dominance maps in the visual cortex (V1). This self-organization process simulates three development phases: an early experience-independent phase, a late experience-independent phase and a subsequent refinement phase during which experience acts to shape the map properties. The ocular dominance maps that emerge accommodate the two sets of monocular inputs that arise from the lateral geniculate nucleus (LGN) to layer 4 of V1. The orientation selectivity maps that emerge feature well-developed iso-orientation domains and fractures. During the last two phases of development the orientation preferences at some locations appear to rotate continuously through ±180° along circular paths and referred to as pinwheel-like patterns but without any corresponding point discontinuities in the orientation gradient maps. The formation of these functional maps is driven by balanced excitatory and inhibitory currents that are established via synaptic plasticity based on spike timing for both excitatory and inhibitory synapses. The stability and maintenance of the formed maps with continuous synaptic plasticity is enabled by homeostasis caused by inhibitory plasticity. However, a prolonged exposure to repeated stimuli does alter the formed maps over time due to plasticity. The results from this study suggest that continuous synaptic plasticity in both excitatory neurons and interneurons could play a critical role in the formation, stability, and maintenance of functional maps in the cortex.

  19. Short-Term Protein Stable Isotope Probing of Microbial Communities to Associate Functions with Taxa (Invited)

    Science.gov (United States)

    Lipton, M. S.; Slysz, G. W.; Steinke, L. A.; Ward, D. M.; Klatt, C. G.; Clauss, T. R.; Purvine, S. O.; Anderson, G. A.; Payne, S. H.; Bryant, D. A.

    2013-12-01

    Determining which taxa in a community perform which functions is essential for understanding metabolite fluxes and metabolic interactions among community members. Specific taxa will alter their metabolism in order to acclimate to changing environmental factors such as light through the diel cycle, changing temperature and other factors. Monitoring which proteins are being expressed, and the quantitative protein expression patterns in the individual taxa as a response to external stimuli is key to understanding these mechanisms. Protein stable isotope probing (Pro-SIP) has strong potential for revealing key metabolizing taxa in complex microbial communities. In Pro-SIP studies, label incorporation is determined by the extent of the change in the isotopic profile of peptides when measured by mass spectrometry. While most Pro-SIP work to date has been performed under controlled laboratory conditions to allow extensive isotope labeling of the target organism(s), these techniques have not been applied to short term in situ studies due to the small degree of partial labeling of the proteins. We have applied Pro-SIP to study the assimilation of a labeled substrate into proteins to determine which taxa are responsible for sequestration of dissolved inorganic carbon in microbial mats associated with the alkaline siliceous hot springs of Yellowstone National Park. This community is fueled by sunlight as it transitions from dark to light; the aim was to understand the light-dependent pathway of inorganic carbon incorporation into different taxa during the early morning hours when the mat was in low light and anoxic. Each mat sample was incubated with 13C-bicarbonate for 3 h. Substrate assimilation was determined through standard proteomic techniques along with the use of SIPPER, a collection of algorithms that sensitively measure small changes in peptide isotopic patterns, allowing the determination of which taxa assimilated the substrate during this period. For the

  20. Guidance of spatial attention during associative learning: Contributions of predictability and intention to learn.

    Science.gov (United States)

    Do Carmo Blanco, Noelia; Allen, John J B

    2018-03-23

    Expectations of an event can facilitate its neural processing. One of the ways we build expectations is through associative learning. Interestingly, the learning of contingencies between events can also occur without intention. Here, we study feature-based attention during associative learning, by asking how a learned association between a cue and a target outcome impacts the attention allocated to this outcome. Moreover, we investigate attention in learning depending on the intention to learn the association. We used an associative learning paradigm where we manipulated outcome predictability and intention to learn an association within streams of cue-target outcome visual stimuli, while stimulus characteristics and probability were held constant. In order to measure the event-related component N2pc, widely recognized to reflect allocation of spatial attention, every outcome was embedded among distractors. Importantly, the location of the target outcome could not be anticipated. We found that predictable target outcomes showed an increased spatial attention as indexed by a greater N2pc component. A later component, the P300, was sensitive to the intention to learn the association between the cue and the target outcome. The current study confirms the remarkable ability of the brain to extract and update predictive information, in accordance with a predictive-coding model of brain function. Associative learning can guide a visual search and shape covert attentional selection in our rich environments. © 2018 Society for Psychophysiological Research.

  1. Progresses in the stable isotope studies of microbial processes associated with wetland methane production

    International Nuclear Information System (INIS)

    Li Qing; Lin Guanghui

    2013-01-01

    Methane emissions from wetlands play a key role in regulating global atmospheric methane concentration, so better understanding of microbial processes for the methane emission in wetlands is critical for developing process models and reducing uncertainty in global methane emission inventory. In this review, we describe basic microbial processes for wetland methane production and then demonstrate how stable isotope fractionation and stable isotope probing can be used to investigate the mechanisms underlying different methanogenic pathways and to quantify microbial species involved in wetland methane production. When applying stable isotope technique to calculate contributions of different pathways to the total methane production in various wetlands, the technical challenge is how to determine isotopic fractionation factors for the acetate derived methane production and carbon dioxide derived methane production. Although the application of stable isotope probing techniques to study the actual functions of different microbial organisms to methane production process is significantly superior to the traditional molecular biology method, the combination of these two technologies will be crucial for direct linking of the microbial community and functional structure with the corresponding metabolic functions, and provide new ideas for future studies. (authors)

  2. Environmental parameters associated with stable fly (Diptera: Muscidae) development at hay feeding sites

    Science.gov (United States)

    Substrates composed of hay residues, dung, and urine accumulate around winter hay feeding sites in cattle pastures, providing developmental habitats for stable flies. The objective of this study was to relate physiochemical and microbial properties of these substrates to the presence or absence of s...

  3. Environmental parameters associated with stable fly development at hay feeding sites

    Science.gov (United States)

    Substrates composed of hay residues, dung, and urine accumulate around winter hay feeding sites in cattle pastures providing developmental habitat for stable flies. The objective of this study was to relate physiochemical and microbial properties of this substrate to the presence or absence of devel...

  4. Commentary: the truth and value of theories of associative learning

    NARCIS (Netherlands)

    Beckers, T.; Vervliet, B.

    2009-01-01

    In this commentary, we assess the propositional approach to associative learning not only in terms of veridicality and falsifiability, but also in heuristic value. We remark that it has furthered our knowledge and understanding of human, as well as animal, associative learning. At the same time, we

  5. The Association between Learning Styles and Perception of Teaching Quality

    Science.gov (United States)

    Jepsen, Denise M.; Varhegyi, Melinda M.; Teo, Stephen T. T.

    2015-01-01

    Purpose: Although learning styles and teaching quality have been studied separately, the association between the association between the two has yet to be identified. The purpose of this paper is to establish the relationship between students' learning styles with students' perceptions of teaching quality. Design/methodology/approach: The study…

  6. Environmental Parameters Associated With Stable Fly (Diptera: Muscidae) Development at Hay Feeding Sites.

    Science.gov (United States)

    Friesen, Kristina; Berkebile, Dennis; Wienhold, Brian; Durso, Lisa; Zhu, Jerry; Taylor, David B

    2016-03-25

    Substrates composed of hay residues, dung, and urine accumulate around winter hay feeding sites in cattle pastures, providing developmental habitats for stable flies. The objective of this study was to relate physiochemical and microbial properties of these substrates to the presence or absence of stable fly larvae. Properties included pH, temperature, moisture, ammonium concentration, electrical conductivity, and numbers of coliform, fecal coliform,Escherichia coli, andEnterococcusbacteria. Each physiochemical sample was classified as a function of belonging to one of the three 2-m concentric zones radiating from the feeder as well as presence or absence of larvae. In total, 538 samples were collected from 13 sites during 2005-2011. Stable fly larvae were most likely to be found in moist, slightly alkaline substrates with high levels of ammonium and low temperature. The probability of larvae being present in a sample was the highest when the moisture content was 347% relative to dry weight and the average pH was 8.4. Larvae were recovered within all zones, with a nonsignificant, but slightly higher, percentage of samples containing larvae taken 2-4 m from the center. All methods used to enumerate bacteria, except total coliform, indicated decreasing concentrations in hay bale residue throughout the summer. In addition to the environmental parameters, cumulative degree day 10°C had a significant effect on the probability of observing stable fly larvae in a sample, indicating that unidentified seasonal effects also influenced immature stable fly populations. Published by Oxford University Press on behalf of Entomological Society of America 2016. This work is written by US Government employees and is in the public domain in the United States.

  7. Two Ways of Learning Brand Associations

    NARCIS (Netherlands)

    S.M.J. van Osselaer (Stijn); C. Janiszewski (Chris)

    2001-01-01

    textabstractFour studies show that consumers have not one but two distinct learning processes that allow them to use brand names and other product features to predict consumption benefits. The first learning process is a relatively unfocused process in which all stimulus elements get

  8. Stable measures of number sense accuracy in math learning disability: Is it time to proceed from basic science to clinical application?

    Science.gov (United States)

    Júlio-Costa, Annelise; Starling-Alves, Isabella; Lopes-Silva, Júlia Beatriz; Wood, Guilherme; Haase, Vitor Geraldi

    2015-12-01

    Math learning disability (MLD) or developmental dyscalculia is a highly prevalent and persistent difficulty in learning arithmetic that may be explained by different cognitive mechanisms. The accuracy of the number sense has been implicated by some evidence as a core deficit in MLD. However, research on this topic has been mainly conducted in demographically selected samples, using arbitrary cut-off scores to characterize MLD. The clinical relevance of the association between number sense and MLD remains to be investigated. In this study, we aimed at assessing the stability of a number sense accuracy measure (w) across five experimental sessions, in two clinically defined cases of MLD. Stable measures of number sense accuracy estimate are required to clinically characterize subtypes of MLD and to make theoretical inferences regarding the underlying cognitive mechanisms. G. A. was a 10-year-old boy with MLD in the context of dyslexia and phonological processing impairment and his performance remained steadily in the typical scores range. The performance of H. V., a 9-year-old girl with MLD associated with number sense inaccuracy, remained consistently impaired across measurements, with a nonsignificant tendency to worsen. Qualitatively, H. V.'s performance was also characterized by greater variability across sessions. Concomitant clinical observations suggested that H. V.'s difficulties could be aggravated by developing symptoms of mathematics anxiety. Results in these two cases are in line with the hypotheses that at least two reliable patterns of cognitive impairment may underlie math learning difficulties in MLD, one related to number sense inaccuracy and the other to phonological processing impairment. Additionally, it indicates the need for more translational research in order to examine the usefulness and validity of theoretical advances in numerical cognition to the clinical neuropsychological practice with MLD. © 2015 The Institute of Psychology, Chinese

  9. Unsupervised learning of complex associations in an animal model.

    Science.gov (United States)

    Castro, Leyre; Wasserman, Edward A; Lauffer, Marisol

    2018-04-01

    Supervised learning results from explicit corrective feedback, whereas unsupervised learning results from statistical co-occurrence. In an initial training phase, we gave pigeons an unsupervised learning task to see if mere pairing could establish associations between multiple pairs of visual images. To assess learning, we administered occasional testing trials in which pigeons were shown an object and had to choose between previously paired and unpaired tokens. Learning was evidenced by preferential choice of the previously unpaired token. In a subsequent supervised training phase, learning was facilitated if the object and token had previously been paired. These results document unsupervised learning in pigeons and resemble statistical learning in infants, suggesting an important parallel between human and animal cognition. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. The role of association in early word-learning

    Directory of Open Access Journals (Sweden)

    Scott P Johnson

    2012-08-01

    Full Text Available Word-learning likely involves a multiplicity of components, some domain-general, others domain-specific. Against the background of recent studies that suggest that word-learning is domain-specific, we investigated the associative component of word-learning. Seven- and 14-month-old infants viewed a pair of events in which a monkey or a truck moved back and forth, accompanied by a sung syllable or a tone, matched for pitch. Following habituation, infants were presented with displays in which the visual-auditory pairings were preserved or switched, and looked longer at the switch events when exposure time was sufficient to learn the intermodal association. At 7 months, performance on speech and tones conditions was statistically identical; at 14 months, infants had begun to favor speech. Thus, the associative component of word-learning does not appear (in contrast to rule-learning, Marcus et al., 2007 to initially privilege speech.

  11. Active Learning Not Associated with Student Learning in a Random Sample of College Biology Courses

    Science.gov (United States)

    Andrews, T. M.; Leonard, M. J.; Colgrove, C. A.; Kalinowski, S. T.

    2011-01-01

    Previous research has suggested that adding active learning to traditional college science lectures substantially improves student learning. However, this research predominantly studied courses taught by science education researchers, who are likely to have exceptional teaching expertise. The present study investigated introductory biology courses randomly selected from a list of prominent colleges and universities to include instructors representing a broader population. We examined the relationship between active learning and student learning in the subject area of natural selection. We found no association between student learning gains and the use of active-learning instruction. Although active learning has the potential to substantially improve student learning, this research suggests that active learning, as used by typical college biology instructors, is not associated with greater learning gains. We contend that most instructors lack the rich and nuanced understanding of teaching and learning that science education researchers have developed. Therefore, active learning as designed and implemented by typical college biology instructors may superficially resemble active learning used by education researchers, but lacks the constructivist elements necessary for improving learning. PMID:22135373

  12. Active learning not associated with student learning in a random sample of college biology courses.

    Science.gov (United States)

    Andrews, T M; Leonard, M J; Colgrove, C A; Kalinowski, S T

    2011-01-01

    Previous research has suggested that adding active learning to traditional college science lectures substantially improves student learning. However, this research predominantly studied courses taught by science education researchers, who are likely to have exceptional teaching expertise. The present study investigated introductory biology courses randomly selected from a list of prominent colleges and universities to include instructors representing a broader population. We examined the relationship between active learning and student learning in the subject area of natural selection. We found no association between student learning gains and the use of active-learning instruction. Although active learning has the potential to substantially improve student learning, this research suggests that active learning, as used by typical college biology instructors, is not associated with greater learning gains. We contend that most instructors lack the rich and nuanced understanding of teaching and learning that science education researchers have developed. Therefore, active learning as designed and implemented by typical college biology instructors may superficially resemble active learning used by education researchers, but lacks the constructivist elements necessary for improving learning.

  13. Stable Atlas-based Mapped Prior (STAMP) machine-learning segmentation for multicenter large-scale MRI data.

    Science.gov (United States)

    Kim, Eun Young; Magnotta, Vincent A; Liu, Dawei; Johnson, Hans J

    2014-09-01

    Machine learning (ML)-based segmentation methods are a common technique in the medical image processing field. In spite of numerous research groups that have investigated ML-based segmentation frameworks, there remains unanswered aspects of performance variability for the choice of two key components: ML algorithm and intensity normalization. This investigation reveals that the choice of those elements plays a major part in determining segmentation accuracy and generalizability. The approach we have used in this study aims to evaluate relative benefits of the two elements within a subcortical MRI segmentation framework. Experiments were conducted to contrast eight machine-learning algorithm configurations and 11 normalization strategies for our brain MR segmentation framework. For the intensity normalization, a Stable Atlas-based Mapped Prior (STAMP) was utilized to take better account of contrast along boundaries of structures. Comparing eight machine learning algorithms on down-sampled segmentation MR data, it was obvious that a significant improvement was obtained using ensemble-based ML algorithms (i.e., random forest) or ANN algorithms. Further investigation between these two algorithms also revealed that the random forest results provided exceptionally good agreement with manual delineations by experts. Additional experiments showed that the effect of STAMP-based intensity normalization also improved the robustness of segmentation for multicenter data sets. The constructed framework obtained good multicenter reliability and was successfully applied on a large multicenter MR data set (n>3000). Less than 10% of automated segmentations were recommended for minimal expert intervention. These results demonstrate the feasibility of using the ML-based segmentation tools for processing large amount of multicenter MR images. We demonstrated dramatically different result profiles in segmentation accuracy according to the choice of ML algorithm and intensity

  14. Working memory and reward association learning impairments in obesity.

    Science.gov (United States)

    Coppin, Géraldine; Nolan-Poupart, Sarah; Jones-Gotman, Marilyn; Small, Dana M

    2014-12-01

    Obesity has been associated with impaired executive functions including working memory. Less explored is the influence of obesity on learning and memory. In the current study we assessed stimulus reward association learning, explicit learning and memory and working memory in healthy weight, overweight and obese individuals. Explicit learning and memory did not differ as a function of group. In contrast, working memory was significantly and similarly impaired in both overweight and obese individuals compared to the healthy weight group. In the first reward association learning task the obese, but not healthy weight or overweight participants consistently formed paradoxical preferences for a pattern associated with a negative outcome (fewer food rewards). To determine if the deficit was specific to food reward a second experiment was conducted using money. Consistent with Experiment 1, obese individuals selected the pattern associated with a negative outcome (fewer monetary rewards) more frequently than healthy weight individuals and thus failed to develop a significant preference for the most rewarded patterns as was observed in the healthy weight group. Finally, on a probabilistic learning task, obese compared to healthy weight individuals showed deficits in negative, but not positive outcome learning. Taken together, our results demonstrate deficits in working memory and stimulus reward learning in obesity and suggest that obese individuals are impaired in learning to avoid negative outcomes. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Novel associative-memory-based self-learning neurocontrol model

    Science.gov (United States)

    Chen, Ke

    1992-09-01

    Intelligent control is an important field of AI application, which is closely related to machine learning, and the neurocontrol is a kind of intelligent control that controls actions of a physical system or a plant. Linear associative memory model is a good analytic tool for artificial neural networks. In this paper, we present a novel self-learning neurocontrol on the basis of the linear associative memory model to support intelligent control. Using our self-learning neurocontrol model, the learning process is viewed as an extension of one of J. Piaget's developmental stages. After a particular linear associative model developed by us is presented, a brief introduction to J. Piaget's cognitive theory is described as the basis of our self-learning style control. It follows that the neurocontrol model is presented, which usually includes two learning stages, viz. primary learning and high-level learning. As a demonstration of our neurocontrol model, an example is also presented with simulation techniques, called that `bird' catches an aim. The tentative experimental results show that the learning and controlling performance of this approach is surprisingly good. In conclusion, future research is pointed out to improve our self-learning neurocontrol model and explore other areas of application.

  16. Comfort and experience with online learning: trends over nine years and associations with knowledge

    Science.gov (United States)

    2014-01-01

    Background Some evidence suggests that attitude toward computer-based instruction is an important determinant of success in online learning. We sought to determine how comfort using computers and perceptions of prior online learning experiences have changed over the past decade, and how these associate with learning outcomes. Methods Each year from 2003–2011 we conducted a prospective trial of online learning. As part of each year’s study, we asked medicine residents about their comfort using computers and if their previous experiences with online learning were favorable. We assessed knowledge using a multiple-choice test. We used regression to analyze associations and changes over time. Results 371 internal medicine and family medicine residents participated. Neither comfort with computers nor perceptions of prior online learning experiences showed a significant change across years (p > 0.61), with mean comfort rating 3.96 (maximum 5 = very comfortable) and mean experience rating 4.42 (maximum 6 = strongly agree [favorable]). Comfort showed no significant association with knowledge scores (p = 0.39) but perceptions of prior experiences did, with a 1.56% rise in knowledge score for a 1-point rise in experience score (p = 0.02). Correlations among comfort, perceptions of prior experiences, and number of prior experiences were all small and not statistically significant. Conclusions Comfort with computers and perceptions of prior experience with online learning remained stable over nine years. Prior good experiences (but not comfort with computers) demonstrated a modest association with knowledge outcomes, suggesting that prior course satisfaction may influence subsequent learning. PMID:24985690

  17. Pigeons acquire multiple categories in parallel via associative learning: a parallel to human word learning?

    Science.gov (United States)

    Wasserman, Edward A; Brooks, Daniel I; McMurray, Bob

    2015-03-01

    Might there be parallels between category learning in animals and word learning in children? To examine this possibility, we devised a new associative learning technique for teaching pigeons to sort 128 photographs of objects into 16 human language categories. We found that pigeons learned all 16 categories in parallel, they perceived the perceptual coherence of the different object categories, and they generalized their categorization behavior to novel photographs from the training categories. More detailed analyses of the factors that predict trial-by-trial learning implicated a number of factors that may shape learning. First, we found considerable trial-by-trial dependency of pigeons' categorization responses, consistent with several recent studies that invoke this dependency to claim that humans acquire words via symbolic or inferential mechanisms; this finding suggests that such dependencies may also arise in associative systems. Second, our trial-by-trial analyses divulged seemingly irrelevant aspects of the categorization task, like the spatial location of the report responses, which influenced learning. Third, those trial-by-trial analyses also supported the possibility that learning may be determined both by strengthening correct stimulus-response associations and by weakening incorrect stimulus-response associations. The parallel between all these findings and important aspects of human word learning suggests that associative learning mechanisms may play a much stronger part in complex human behavior than is commonly believed. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. [Factors associated with self-directed learning among medical students].

    Science.gov (United States)

    Spormann R, Camila; Pérez V, Cristhian; Fasce H, Eduardo; Ortega B, Javiera; Bastías V, Nancy; Bustamante D, Carolina; Ibáñez G, Pilar

    2015-03-01

    Self-directed learning is a skill that must be taught and evaluated in future physicians. To analyze the association between self-directed learning, self-esteem, self-efficacy, time management and academic commitment among medical students. The self-directed learning, Rosemberg self-esteem, general self- efficacy, time management and Utrecht work engagement scales were applied to 297 first year medical students. A multiple regression analysis showed a significant association between self-efficacy, time management and academic commitment with self-directed learning. Self-esteem and satisfaction with studies did not enter in the model. self-esteem, academic commitment and a good time management were associated with self-directed learning in these students.

  19. An associative account of the development of word learning.

    Science.gov (United States)

    Sloutsky, Vladimir M; Yim, Hyungwook; Yao, Xin; Dennis, Simon

    2017-09-01

    Word learning is a notoriously difficult induction problem because meaning is underdetermined by positive examples. How do children solve this problem? Some have argued that word learning is achieved by means of inference: young word learners rely on a number of assumptions that reduce the overall hypothesis space by favoring some meanings over others. However, these approaches have difficulty explaining how words are learned from conversations or text, without pointing or explicit instruction. In this research, we propose an associative mechanism that can account for such learning. In a series of experiments, 4-year-olds and adults were presented with sets of words that included a single nonsense word (e.g. dax). Some lists were taxonomic (i.,e., all items were members of a given category), some were associative (i.e., all items were associates of a given category, but not members), and some were mixed. Participants were asked to indicate whether the nonsense word was an animal or an artifact. Adults exhibited evidence of learning when lists consisted of either associatively or taxonomically related items. In contrast, children exhibited evidence of word learning only when lists consisted of associatively related items. These results present challenges to several extant models of word learning, and a new model based on the distinction between syntagmatic and paradigmatic associations is proposed. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. [Associative Learning between Orientation and Color in Early Visual Areas].

    Science.gov (United States)

    Amano, Kaoru; Shibata, Kazuhisa; Kawato, Mitsuo; Sasaki, Yuka; Watanabe, Takeo

    2017-08-01

    Associative learning is an essential neural phenomenon where the contingency of different items increases after training. Although associative learning has been found to occur in many brain regions, there is no clear evidence that associative learning of visual features occurs in early visual areas. Here, we developed an associative decoded functional magnetic resonance imaging (fMRI) neurofeedback (A-DecNef) to determine whether associative learning of color and orientation can be induced in early visual areas. During the three days' training, A-DecNef induced fMRI signal patterns that corresponded to a specific target color (red) mostly in early visual areas while a vertical achromatic grating was simultaneously, physically presented to participants. Consequently, participants' perception of "red" was significantly more frequently than that of "green" in an achromatic vertical grating. This effect was also observed 3 to 5 months after training. These results suggest that long-term associative learning of two different visual features such as color and orientation, was induced most likely in early visual areas. This newly extended technique that induces associative learning may be used as an important tool for understanding and modifying brain function, since associations are fundamental and ubiquitous with respect to brain function.

  1. I. P. PAVLOV: 100 YEARS OF RESERACH ON ASSOCIATIVE LEARNING

    Directory of Open Access Journals (Sweden)

    GERMÁN GUTIÉRREZ

    2005-07-01

    Full Text Available A biographical summary of Ivan Pavlov is presented, emphasizing his academic formation and achievements, and hiscontributions to general science and psychology. His main findings on associative learning are described and three areasof current development in this area are discussed: the study of behavioral mechanisms, the study of neurobiologicalmechanisms and the functional role of learning.

  2. Differential Recruitment of Distinct Amygdalar Nuclei across Appetitive Associative Learning

    Science.gov (United States)

    Cole, Sindy; Powell, Daniel J.; Petrovich, Gorica D.

    2013-01-01

    The amygdala is important for reward-associated learning, but how distinct cell groups within this heterogeneous structure are recruited during appetitive learning is unclear. Here we used Fos induction to map the functional amygdalar circuitry recruited during early and late training sessions of Pavlovian appetitive conditioning. We found that a…

  3. Factors associated with successful self-directed learning using individualized learning plans during pediatric residency.

    Science.gov (United States)

    Li, Su-Ting T; Tancredi, Daniel J; Co, John Patrick T; West, Daniel C

    2010-01-01

    The aim of this study was to determine whether resident or program characteristics are associated with effective self-directed learning of residents. A cross-sectional survey of pediatric and medicine/pediatric residents and program directors from a nationally representative sample of residency programs was conducted. Self-directed learning efficacy was measured by resident-reported progress on learning goals from their most recent individualized learning plan (ILP). Multilevel linear regression models were used to analyze the relationship between learner and program characteristics and self-directed learning efficacy of residents. All program directors of participating programs (N = 46) completed the survey; the response rate from residents was 57% (992/1739). At the time of the survey, 78% of residents had previously written an ILP. Most residents achieved moderate self-directed learning efficacy. The most important factors associated with greater self-directed learning efficacy included using a system to track one's own progress in achieving learning goals, higher score on a propensity toward lifelong learning scale, and reporting greater confidence in self-directed learning abilities. Program characteristics, including program-level support for ILPs, had little or mixed association with resident self-directed learning efficacy. The most important factors associated with effective self-directed learning were resident characteristics. Our findings imply that residency programs should invest their limited resources in curricula that help residents develop measurable goals and systems for tracking progress toward goal attainment. Since propensity toward lifelong learning was an important factor, medical schools and residency training programs should enhance their efforts to develop this characteristic in learners. Copyright 2010 Academic Pediatric Association. Published by Elsevier Inc. All rights reserved.

  4. Associative Learning Improves Visual Working Memory Performance

    Science.gov (United States)

    Olson, Ingrid R.; Jiang, Yuhong; Moore, Katherine Sledge

    2005-01-01

    The ability to remember visual stimuli over a short delay period is limited by the small capacity of visual working memory (VWM). Here the authors investigate the role of learning in enhancing VWM. Participants saw 2 spatial arrays separated by a 1-s interval. The 2 arrays were identical except for 1 location. Participants had to detect the…

  5. Metabolic syndrome is independently associated with increased 20-year mortality in patients with stable coronary artery disease.

    Science.gov (United States)

    Younis, Arwa; Younis, Anan; Tzur, Boaz; Peled, Yael; Shlomo, Nir; Goldenberg, Ilan; Fisman, Enrique Z; Tenenbaum, Alexander; Klempfner, Robert

    2016-10-28

    Data regarding long-term association of metabolic syndrome (MetS) with adverse outcomes are conflicting. We aim to determine the independent association of MetS (based on its different definitions) with 20 year all-cause mortality among patients with stable coronary artery disease (CAD). Our study comprised 15,524 patients who were enrolled in the Bezafibrate Infarction Prevention registry between February 1, 1990, and October 31, 1992, and subsequently followed-up for the long-term mortality through December 31, 2014. MetS was defined according to two definitions: The International Diabetes Federation (IDF); and the National Cholesterol Education Program-Third Adult Treatment Panel (NCEP). According to the IDF criteria 2122 (14%) patients had MetS, whereas according to the NCEP definition 7446 (48%) patients had MetS. Kaplan-Meier survival analysis showed that all-cause mortality was significantly higher among patients with MetS defined by both the IDF (67 vs. 61%; log rank-p definition. Subgroup analysis demonstrated that long-term increased mortality risk associated with MetS was consistent among most clinical subgroups excepted patients with renal failure (p value for interaction Metabolic syndrome is independently associated with an increased 20-year all-cause mortality risk among patients with stable CAD. This association was consistent when either the IDF or NCEP definitions were used. Trial registration retrospective registered.

  6. Is going into stable symptomatic remission associated with a more positive development of life satisfaction?

    DEFF Research Database (Denmark)

    Gardsjord, Erlend Strand; Romm, Kristin Lie; Røssberg, Jan Ivar

    2017-01-01

    by the Remission in Schizophrenia Working Group. One-way ANOVA, mixed model analysis, bivariate correlations and multiple regression analyses were performed. RESULTS: Patients going into stable symptomatic remission showed a more positive S-QoL-development over the follow-up period and reported higher life...... satisfaction at 10-year follow-up compared to non-remission. At 10-year follow-up, depressive symptoms and alcohol abuse or dependence explained a significant amount of variance in S-QoL among patients in remission. Among patients in non-remission, PANSS excitative component explained a significant amount...... implications. While patients in remission might need treatment for depressive symptoms to increase S-QoL, in non-remission measures aiming to decrease hostility and uncooperativeness should be part of the treatment approach. Alcohol problems should be treated regardless of remission status....

  7. Association Between Pathogens Detected Using Quantitative Polymerase Chain Reaction With Airway Inflammation in COPD at Stable State and Exacerbations

    Science.gov (United States)

    Barker, Bethan L.; Haldar, Koirobi; Patel, Hemu; Pavord, Ian D.; Barer, Michael R.; Brightling, Christopher E.

    2015-01-01

    BACKGROUND: Relationships between airway inflammation and respiratory potentially pathogenic microorganisms (PPMs) quantified using quantitative polymerase chain reaction (qPCR) in subjects with COPD are unclear. Our aim was to evaluate mediators of airway inflammation and their association with PPMs in subjects with COPD at stable state and during exacerbations. METHODS: Sputum from 120 stable subjects with COPD was analyzed for bacteriology (colony-forming units; total 16S; and qPCR targeting Haemophilus influenzae, Moraxella catarrhalis, and Streptococcus pneumoniae), differential cell counts, and inflammatory mediators using the Meso-Scale Discovery Platform. Subjects were classified as colonized if any PPM was identified above the threshold of detection by qPCR. Symptoms were quantified using the visual analog scale. RESULTS: At stable state, 60% of subjects were qPCR positive for H influenzae, 48% for M catarrhalis, and 28% for S pneumoniae. Elevated sputum concentrations of IL-1β, IL-10, and tumor necrosis factor (TNF)-α were detected in samples qPCR positive for either H influenzae or M catarrhalis. Bacterial loads of H influenzae positively correlated with IL-1β, IL-8, IL-10, TNF-α, and symptoms; and M catarrhalis correlated with IL-10 and TNF-α. H influenzae qPCR bacterial load was an independent predictor of sputum TNF-α and IL-1β. In 55 subjects with paired exacerbation data, qPCR bacterial load fold change at exacerbation in M catarrhalis but not H influenzae correlated to changes in sputum TNF-α and IL-1β concentrations. CONCLUSIONS: At stable state, H influenzae is associated with increased airway inflammation in COPD. The relationship between bacterial load changes of specific pathogens and airway inflammation at exacerbation and recovery warrants further investigation. PMID:25103335

  8. Associative Learning of Social Value in Dynamic Groups.

    Science.gov (United States)

    FeldmanHall, Oriel; Dunsmoor, Joseph E; Kroes, Marijn C W; Lackovic, Sandra; Phelps, Elizabeth A

    2017-08-01

    Although humans live in societies that regularly demand engaging with multiple people simultaneously, little is known about social learning in group settings. In two experiments, we combined a Pavlovian learning framework with dyadic economic games to test whether blocking mechanisms support value-based social learning in the gain (altruistic dictators) and loss (greedy robbers) domains. Subjects first learned about an altruistic dictator, who subsequently made altruistic splits collectively with a partner. Results revealed that because the presence of the dictator already predicted the outcome, subjects did not learn to associate value with the partner. This social blocking effect was not observed in the loss domain: A kind robber's partner, who could steal all the subjects' money but stole little, acquired highly positive value-which biased subjects' subsequent behavior. These findings reveal how Pavlovian mechanisms support efficient social learning, while also demonstrating that violations of social expectations can attenuate how readily these mechanisms are recruited.

  9. Stable schizophrenia patients learn equally well as age-matched controls and better than elderly controls in two sensorimotor Rotary Pursuit tasks

    Directory of Open Access Journals (Sweden)

    Livia J. De Picker

    2014-11-01

    Full Text Available Objective: To compare sensorimotor performance and learning in stable schizophrenia patients, healthy age- and sex-matched controls and elderly controls on two variations of the Rotary Pursuit: Circle Pursuit (true motor learning and Figure Pursuit (motor and sequence learning.Method: In the Circle Pursuit a target circle, rotating with increasing speed along a predictable circular path on the computer screen, must be followed by a cursor controlled by a pen on a writing tablet. In the eight-trial Figure Pursuit, subjects learn to draw a complex figure by pursuing the target circle that moves along an invisible trajectory between and around several goals. Tasks were administered thrice (day 1, day 2, day 7 to 30 patients with stable schizophrenia (S, 30 healthy age- and sex-matched controls (C and 30 elderly participants (>65y; E and recorded with a digitizing tablet and pressure-sensitive pen. The outcome measure accuracy (% of time that cursor is within the target was used to assess performance.Results: We observed significant group differences in accuracy, both in Circle and Figure Pursuit tasks (Elearning effects were found in each group. Learning curves were similar in Circle Pursuit but differed between groups in Figure Pursuit. When corrected for group differences in starting level, the learning gains over the three sessions of schizophrenia patients and age-matched controls were equal and both were larger than those of the elderly controls. Conclusion: Despite the reduced sensorimotor performance that was found in the schizophrenia patients their sensorimotor learning seems to be preserved. The relevance of this finding for the evaluation of procedural learning in schizophrenia is discussed. The better performance and learning rate of the patients compared to the elderly controls was unexpected and deserves further study.

  10. Optical implementations of associative networks with versatile adaptive learning capabilities.

    Science.gov (United States)

    Fisher, A D; Lippincott, W L; Lee, J N

    1987-12-01

    Optical associative, parallel-processing architectures are being developed using a multimodule approach, where a number of smaller, adaptive, associative modules are nonlinearly interconnected and cascaded under the guidance of a variety of organizational principles to structure larger architectures for solving specific problems. A number of novel optical implementations with versatile adaptive learning capabilities are presented for the individual associative modules, including holographic configurations and five specific electrooptic configurations. The practical issues involved in real optical architectures are analyzed, and actual laboratory optical implementations of associative modules based on Hebbian and Widrow-Hoff learning rules are discussed, including successful experimental demonstrations of their operation.

  11. Incidental Learning of Rewarded Associations Bolsters Learning on an Associative Task

    Science.gov (United States)

    Freedberg, Michael; Schacherer, Jonathan; Hazeltine, Eliot

    2016-01-01

    Reward has been shown to change behavior as a result of incentive learning (by motivating the individual to increase their effort) and instrumental learning (by increasing the frequency of a particular behavior). However, Palminteri et al. (2011) demonstrated that reward can also improve the incidental learning of a motor skill even when…

  12. The association between self-esteem and happiness differs in relationally mobile vs. stable interpersonal contexts

    OpenAIRE

    Sato, Kosuke; Yuki, Masaki

    2014-01-01

    Does a change in the nature of surrounding social context affect the strength of association between self-esteem and happiness? This paper aims to answer this question from a socio-ecological perspective, focusing on the role of relational mobility. Recent research has shown that this association is stronger in societies that are higher in relational mobility, where there is a greater freedom of choice in interpersonal relationships and group memberships. In this study, we tested if this hypo...

  13. Till death do us part: stable sponge-bacteria associations under thermal and food shortage stresses.

    Directory of Open Access Journals (Sweden)

    Lucía Pita

    Full Text Available Sporadic mass mortality events of Mediterranean sponges following periods of anomalously high temperatures or longer than usual stratification of the seawater column (i.e. low food availability suggest that these animals are sensitive to environmental stresses. The Mediterranean sponges Ircinia fasciculata and I. oros harbor distinct, species-specific bacterial communities that are highly stable over time and space but little is known about how anomalous environmental conditions affect the structure of the resident bacterial communities. Here, we monitored the bacterial communities in I. fasciculata (largely affected by mass mortalities and I. oros (overall unaffected maintained in aquaria during 3 weeks under 4 treatments that mimicked realistic stress pressures: control conditions (13°C, unfiltered seawater, low food availability (13°C, 0.1 µm-filtered seawater, elevated temperatures (25°C, unfiltered seawater, and a combination of the 2 stressors (25°C, 0.1 µm-filtered seawater. Bacterial community structure was assessed using terminal restriction fragment length polymorphism (T-RFLP analysis of 16S rRNA gene sequences and transmission electron microscopy (TEM. As I. fasciculata harbors cyanobacteria, we also measured chlorophyll a (chl a levels in this species. Multivariate analysis revealed no significant differences in bacterial T-RFLP profiles among treatments for either host sponge species, indicating no effect of high temperatures and food shortage on symbiont community structure. In I. fasciculata, chl a content did not significantly differ among treatments although TEM micrographs revealed some cyanobacteria cells undergoing degradation when exposed to both elevated temperature and food shortage conditions. Arguably, longer-term treatments (months could have eventually affected bacterial community structure. However, we evidenced no appreciable decay of the symbiotic community in response to medium-term (3 weeks environmental

  14. Olfactory Perceptual Learning Requires Action of Noradrenaline in the Olfactory Bulb: Comparison with Olfactory Associative Learning

    Science.gov (United States)

    Vinera, Jennifer; Kermen, Florence; Sacquet, Joëlle; Didier, Anne; Mandairon, Nathalie; Richard, Marion

    2015-01-01

    Noradrenaline contributes to olfactory-guided behaviors but its role in olfactory learning during adulthood is poorly documented. We investigated its implication in olfactory associative and perceptual learning using local infusion of mixed a1-ß adrenergic receptor antagonist (labetalol) in the adult mouse olfactory bulb. We reported that…

  15. Transfer of dimensional associability in human contingency learning.

    Science.gov (United States)

    Kattner, Florian; Green, C Shawn

    2016-01-01

    Several studies have demonstrated processing advantages for stimuli that were experienced to be reliable predictors of an outcome relative to other stimuli. The present study tested whether such increases in associability apply at the level of entire stimulus dimensions (as suggested by Sutherland & Mackintosh, 1971). In 4 experiments, participants had to learn associations between Gabor gratings and particular responses. In a first experiment, some gratings were more predictive of the response than other gratings, whereas in 3 subsequent experiments, one stimulus dimension (i.e., either the orientation or spatial frequency of the grating) was more predictive than the other dimension. In contrast to the learned predictiveness of individual gratings (Experiment 1), dimensional predictiveness did not affect the subsequent rate of learning (Experiments 2 and 3), suggesting changes in the associability of specific stimuli, but not of stimulus dimensions. Moreover, greater transfer of predictiveness was found in all experiments when particular stimulus values of the test discrimination did not lie between the previously relevant stimuli. In Experiment 4, an increased learning rate was found for discriminations along the previously predictive dimension compared with a dimension that was indicative of uncertainty, but again the transfer was more pronounced for specific stimuli that were compatible with the previously learned discrimination. Taken together, the results imply that a transfer of associability typically applies to individual stimuli and depends on how the transfer stimuli relate to those stimuli that individuals previously learned to attend. (c) 2016 APA, all rights reserved).

  16. Semantic and associative factors in probability learning with words.

    Science.gov (United States)

    Schipper, L M; Hanson, B L; Taylor, G; Thorpe, J A

    1973-09-01

    Using a probability-learning technique with a single word as the cue and with the probability of a given event following this word fixed at .80, it was found (1) that neither high nor low associates to the original word and (2) that neither synonyms nor antonyms showed differential learning curves subsequent to original learning when the probability for the following event was shifted to .20. In a second study when feedback, in the form of knowledge of results, was withheld, there was a clear-cut similarity of predictions to the originally trained word and the synonyms of both high and low association value and a dissimilarity of these words to a set of antonyms of both high and low association value. Two additional studies confirmed the importance of the semantic dimension as compared with association value as traditionally measured.

  17. Critical evidence for the prediction error theory in associative learning.

    Science.gov (United States)

    Terao, Kanta; Matsumoto, Yukihisa; Mizunami, Makoto

    2015-03-10

    In associative learning in mammals, it is widely accepted that the discrepancy, or error, between actual and predicted reward determines whether learning occurs. Complete evidence for the prediction error theory, however, has not been obtained in any learning systems: Prediction error theory stems from the finding of a blocking phenomenon, but blocking can also be accounted for by other theories, such as the attentional theory. We demonstrated blocking in classical conditioning in crickets and obtained evidence to reject the attentional theory. To obtain further evidence supporting the prediction error theory and rejecting alternative theories, we constructed a neural model to match the prediction error theory, by modifying our previous model of learning in crickets, and we tested a prediction from the model: the model predicts that pharmacological intervention of octopaminergic transmission during appetitive conditioning impairs learning but not formation of reward prediction itself, and it thus predicts no learning in subsequent training. We observed such an "auto-blocking", which could be accounted for by the prediction error theory but not by other competitive theories to account for blocking. This study unambiguously demonstrates validity of the prediction error theory in associative learning.

  18. Word learning emerges from the interaction of online referent selection and slow associative learning

    Science.gov (United States)

    McMurray, Bob; Horst, Jessica S.; Samuelson, Larissa K.

    2013-01-01

    Classic approaches to word learning emphasize the problem of referential ambiguity: in any naming situation the referent of a novel word must be selected from many possible objects, properties, actions, etc. To solve this problem, researchers have posited numerous constraints, and inference strategies, but assume that determining the referent of a novel word is isomorphic to learning. We present an alternative model in which referent selection is an online process that is independent of long-term learning. This two timescale approach creates significant power in the developing system. We illustrate this with a dynamic associative model in which referent selection is simulated as dynamic competition between competing referents, and learning is simulated using associative (Hebbian) learning. This model can account for a range of findings including the delay in expressive vocabulary relative to receptive vocabulary, learning under high degrees of referential ambiguity using cross-situational statistics, accelerating (vocabulary explosion) and decelerating (power-law) learning rates, fast-mapping by mutual exclusivity (and differences in bilinguals), improvements in familiar word recognition with development, and correlations between individual differences in speed of processing and learning. Five theoretical points are illustrated. 1) Word learning does not require specialized processes – general association learning buttressed by dynamic competition can account for much of the literature. 2) The processes of recognizing familiar words are not different than those that support novel words (e.g., fast-mapping). 3) Online competition may allow the network (or child) to leverage information available in the task to augment performance or behavior despite what might be relatively slow learning or poor representations. 4) Even associative learning is more complex than previously thought – a major contributor to performance is the pruning of incorrect associations

  19. Factors associated with learning outcome of BSN in a blended learning environment.

    Science.gov (United States)

    Hsu, Li-Ling; Hsieh, Suh-Ing

    2011-01-01

    This paper is a report of a study to examine the influence of demographic, learning behavior and learning performance variables on learning outcomes of baccalaureate nursing students within a blended learning environment. A cross-sectional survey was conducted using the self-structured demographic questionnaire, case analysis attitude scale (CAAS), the case analysis self-evaluation scales (CASES), the metacognition scale (MS) and blended learning satisfaction scale (BLSS) to measure learning outcomes after the blended learning course. A total of 99 senior undergraduate nursing students currently studying at a public nursing college in Taiwan were eligible to participate in the study in 2008. Data were analyzed by descriptive statistics and multiple linear regression. Univariate analysis showed significant associations between frequency of online dialogues, time spent on the internet, CAAS, and MS and scores on the ethical course. However, frequency of online dialogues, time spent on the internet, and the CAAS were significantly independent predictors for scores on the ethical course in the final model of multivariate analysis. The final model of the data analysis could account for 78% variances scores of ethical course (R(2) = 0.78 and adjusted R(2) = 0.77). It can be concluded from this study that frequency of online dialogue, time spent on internet, and the CAAS score are all useful predictors for learning outcome. In addition, blended learning was found to have contributed to learners' learning outcome by facilitating their metacognitive development and self-regulatory development. In blended learning courses, students have more responsibilities placed upon them than in traditional face-to-face learning environments. The first step of constructing a working blended learning model is to develop student-oriented teaching pedagogies that include face-to-face and online instruction, rather than just focusing on the provision of technical skills.

  20. Towards a New Study on Associative Learning in Human Fetuses: Fetal Associative Learning in Primates

    Science.gov (United States)

    Kawai, Nobuyuki

    2010-01-01

    Research has revealed that fetuses can learn from events in their environment. The most convincing evidence for fetal learning is habituation to vibroacoustic stimulation (VAS) in human fetuses and classical conditioning in rat fetuses. However, these two research areas have been independent of each other. There have been few attempts at classical…

  1. Nitrogen acquisition, transport and metabolism in intact ectomycorrhizal associations studied by 15N stable isotope techniques

    International Nuclear Information System (INIS)

    Ek, H.

    1993-05-01

    The focus of this thesis is on the external mycelium and its role in nitrogen uptake, assimilation and translocation. Tree seedlings in association with ectomycorrhizal fungi were grown in observation chambers. The fungal mycelium were fed with 15-N ammonium or 15-N nitrate or a combination of both. The effects of Collembola on the ectomycorrhizal symbiosis were also studied. The results demonstrates an important role of the external mycelium of Paxillus involutus not only in the uptake but also in the assimilation of ammonium into a variety of different amino acids, primarily glutamine but also glutamic acid, aspartic acid, and alanine, immediately after uptake. The results indicate that ammonium is assimilated by GS and GOGAT or GDH in the mycelium at the uptake site. When nitrate was added to the mycelium as the sole nitrogen source nitrate was reduced in the mycelium and the product assimilated into amino acids. When ammonium nitrate was supplied to the fungal mycelium nitrate was taken up the fungus and transferred to the plant, however, apparently no assimilation of nitrate occurred in the external mycelium. Ammonium or an assimilation product, such as glutamine, probably represses nitrate reductase (NR) but not nitrate uptake and transfer in P. involutus. P. involutus nitrogen uptake and transfer to the associated mycorrhizal pine was up to 76% higher when low numbers of the Collembola Onychiurus armatus were present compared to when they were completely absent. This was probably an indirect effect as P. involutus hyphal growth rate and extramatrical biomass increased at a low Collembola density. At high Collembola densities P. involutus hyphal growth rate was retarded. (74 refs.)

  2. Neural dynamics of learning sound-action associations.

    Directory of Open Access Journals (Sweden)

    Adam McNamara

    Full Text Available A motor component is pre-requisite to any communicative act as one must inherently move to communicate. To learn to make a communicative act, the brain must be able to dynamically associate arbitrary percepts to the neural substrate underlying the pre-requisite motor activity. We aimed to investigate whether brain regions involved in complex gestures (ventral pre-motor cortex, Brodmann Area 44 were involved in mediating association between novel abstract auditory stimuli and novel gestural movements. In a functional resonance imaging (fMRI study we asked participants to learn associations between previously unrelated novel sounds and meaningless gestures inside the scanner. We use functional connectivity analysis to eliminate the often present confound of 'strategic covert naming' when dealing with BA44 and to rule out effects of non-specific reductions in signal. Brodmann Area 44, a region incorporating Broca's region showed strong, bilateral, negative correlation of BOLD (blood oxygen level dependent response with learning of sound-action associations during data acquisition. Left-inferior-parietal-lobule (l-IPL and bilateral loci in and around visual area V5, right-orbital-frontal-gyrus, right-hippocampus, left-para-hippocampus, right-head-of-caudate, right-insula and left-lingual-gyrus also showed decreases in BOLD response with learning. Concurrent with these decreases in BOLD response, an increasing connectivity between areas of the imaged network as well as the right-middle-frontal-gyrus with rising learning performance was revealed by a psychophysiological interaction (PPI analysis. The increasing connectivity therefore occurs within an increasingly energy efficient network as learning proceeds. Strongest learning related connectivity between regions was found when analysing BA44 and l-IPL seeds. The results clearly show that BA44 and l-IPL is dynamically involved in linking gesture and sound and therefore provides evidence that one of

  3. Smaller Fixation Target Size Is Associated with More Stable Fixation and Less Variance in Threshold Sensitivity.

    Directory of Open Access Journals (Sweden)

    Kazunori Hirasawa

    Full Text Available The aims of this randomized observational case control study were to quantify fixation behavior during standard automated perimetry (SAP with different fixation targets and to evaluate the relationship between fixation behavior and threshold variability at each test point in healthy young participants experienced with perimetry. SAP was performed on the right eyes of 29 participants using the Octopus 900 perimeter, program 32, dynamic strategy. The fixation targets of Point, Cross, and Ring were used for SAP. Fixation behavior was recorded using a wearable eye-tracking glass. All participants underwent SAP twice with each fixation target in a random fashion. Fixation behavior was quantified by calculating the bivariate contour ellipse area (BCEA and the frequency of deviation from the fixation target. The BCEAs (deg2 of Point, Cross, and Ring targets were 1.11, 1.46, and 2.02, respectively. In all cases, BCEA increased significantly with increasing fixation target size (p < 0.05. The logarithmic value of BCEA demonstrated the same tendency (p < 0.05. A positive correlation was identified between fixation behavior and threshold variability for the Point and Cross targets (ρ = 0.413-0.534, p < 0.05. Fixation behavior increased with increasing fixation target size. Moreover, a larger fixation behavior tended to be associated with a higher threshold variability. A small fixation target is recommended during the visual field test.

  4. Learning to associate orientation with color in early visual areas by associative decoded fMRI neurofeedback

    OpenAIRE

    Amano, Kaoru; Shibata, Kazuhisa; Kawato, Mitsuo; Sasaki, Yuka; Watanabe, Takeo

    2016-01-01

    Associative learning is an essential brain process where the contingency of different items increases after training. Associative learning has been found to occur in many brain regions [1-4]. However, there is no clear evidence that associative learning of visual features occurs in early visual areas, although a number of studies have indicated that learning of a single visual feature (perceptual learning) involves early visual areas [5-8]. Here, via decoded functional magnetic resonance imag...

  5. Association between Depression, Pressure Pain Sensitivity, Stress and Autonomous Nervous System Function in Stable Ischemic Heart Disease

    DEFF Research Database (Denmark)

    Ballegaard, Søren; Bergmann, Natasha; Karpatschof, Benny

    2016-01-01

    Background: Depression and ischemic heart disease (IHD) are associated with persistent stress and autonomic nervous system (ANS) dysfunction. The former can be measured by pressure pain sensitivity (PPS) of the sternum, and the latter by the PPS and systolic blood pressure (SBP) response to a tilt...... table test (TTT). Beta-blocker treatment reduces the efferent beta-adrenergic ANS function, and thus, the physiological stress response. Objective: To test the effect of beta-blockers on changes in depression score in patients with IHD, as well as the influence on persistent stress and ANS dysfunction....... Methods: Three months of non-pharmacological intervention aiming at reducing PPS and depression score in patients with stable IHD. Beta-blocker users (N = 102) were compared with non-users (N = 75), with respect to signs of depression measured by the Major Depressive Inventory questionnaire (MDI), resting...

  6. Paired Associate Learning in Chinese Children with Dyslexia

    Science.gov (United States)

    Li, Hong; Shu, Hua; McBride-Chang, Catherine; Liu, Hong Yun; Xue, Jin

    2009-01-01

    A total of 82 Chinese 11- and 12-year-olds with and without dyslexia were tested on four paired associate learning (PAL) tasks, phonological awareness, morphological awareness, rapid naming, and verbal short-term memory in three different experiments. Experiment 1 demonstrated that children with dyslexia were significantly poorer in visual-verbal…

  7. Remodeling of Hippocampal Synapses After Hippocampus-Dependent Associative Learning

    NARCIS (Netherlands)

    Geinisman, Yuri; Disterhoft, John F.; Gundersen, Hans Jørgen G.; McEchron, Matthew D.; Persina, Inna S.; Power, John M.; Zee, Eddy A. van der; West, Mark J.

    2000-01-01

    The aim of this study was to determine whether hippocampus-dependent associative learning involves changes in the number and/or structure of hippocampal synapses. A behavioral paradigm of trace eyeblink conditioning was used. Young adult rabbits were given daily 80 trial sessions to a criterion of

  8. Challenges Associated with Teaching and Learning of English ...

    African Journals Online (AJOL)

    This paper discussed the challenges which are associated with the teaching and learning of English Grammar in Nigeria secondary schools. Grammar is the spinal cord of any language and the user's mastery of it determines his competence and performance in the language. Furthermore, the factors which make teaching ...

  9. Evaluation of the contamination by stable and unstable isotopes in the coastal zones associated to hydrographic basins of Costa Rica

    International Nuclear Information System (INIS)

    Loria Meneses, Luis Guillermo; Lizano Rodriguez, Omar G.; Salazar Matarrita, Alfonso; Jimenez Dam, Ricardo

    2003-01-01

    The degree of contamination by the stable and unstable isotopes concentration in sediments of beaches of Costa Rica is evaluated. It establishes relations between the trace elements in sediments from beaches not associated to hydrographic basins and associated sediments to basins. The totality of sediments coming of beaches were analyzed by the technique of gamma spectroscopy and x-rays spectroscopy. It was determined that the beaches associated to bays and gulfs present greater concentrations as for the presence of radioactive isotopes. In addition, the existing concentrations for unstable isotopes present low values in the zones of open sea; whereas the values of radiation background in beaches and gulfs allow, to future, to detect if is presenting anthropogenic contamination of origin in that type of isotopes or could be a greater presence of these. The obtained results show that the values of radiation of background in beaches were unknown, as well as the unstable isotopes concentration. Also was found the presence of Cs 137, which comes normally from nuclear blasts. The work already includes two published documents [es

  10. Exploratory study of the association between insight and Theory of Mind (ToM) in stable schizophrenia patients.

    Science.gov (United States)

    Pousa, Esther; Duñó, Rosó; Blas Navarro, J; Ruiz, Ada I; Obiols, Jordi E; David, Anthony S

    2008-05-01

    Poor insight and impairment in Theory of Mind (ToM) reasoning are common in schizophrenia, predicting poorer clinical and functional outcomes. The present study aimed to explore the relationship between these phenomena. 61 individuals with a DSM-IV diagnosis of schizophrenia during a stable phase were included. ToM was assessed using a picture sequencing task developed by Langdon and Coltheart (1999), and insight with the Scale to Assess Unawareness of Mental Disorder (SUMD; Amador et al., 1993). Multivariate linear regression analysis was carried out to estimate the predictive value of insight on ToM, taking into account several possible confounders and interaction variables. No direct significant associations were found between any of the insight dimensions and ToM using bivariate analysis. However, a significant linear regression model which explained 48% of the variance in ToM was revealed in the multivariate analysis. This included the 5 insight dimensions and 3 interaction variables. Misattribution of symptoms--in aware patients with age at onset >20 years--and unawareness of need for medication--in patients with GAF >60--were significantly predictive of better ToM. Insight and ToM are two complex and distinct phenomena in schizophrenia. Relationships between them are mediated by psychosocial, clinical, and neurocognitive variables. Intact ToM may be a prerequisite for aware patients to attribute their symptoms to causes other than mental illness, which could in turn be associated with denial of need for medication.

  11. Factors associated with health-related quality of life in stable ambulatory congestive heart failure patients: Systematic review.

    Science.gov (United States)

    Baert, Anneleen; De Smedt, Delphine; De Sutter, Johan; De Bacquer, Dirk; Puddu, Paolo Emilio; Clays, Els; Pardaens, Sofie

    2018-03-01

    Background Since improved treatment of congestive heart failure has resulted in decreased mortality and hospitalisation rates, increasing self-perceived health-related quality of life (HRQoL) has become a major goal of congestive heart failure treatment. However, an overview on predictieve factors of HRQoL is currently lacking in literature. Purpose The aim of this study was to identify key factors associated with HRQoL in stable ambulatory patients with congestive heart failure. Methods A systematic review was performed. MEDLINE, Web of Science and Embase were searched for the following combination of terms: heart failure, quality of life, health perception or functional status between the period 2000 and February 2017. Literature screening was done by two independent reviewers. Results Thirty-five studies out of 8374 titles were included for quality appraisal, of which 29 were selected for further data extraction. Four distinct categories grouping different types of variables were identified: socio-demographic characteristics, clinical characteristics, health and health behaviour, and care provider characteristics. Within the above-mentioned categories the presence of depressive symptoms was most consistently related to a worse HRQoL, followed by a higher New York Heart Association functional class, younger age and female gender. Conclusion Through a systematic literature search, factors associated with HRQoL among congestive heart failure patients were investigated. Age, gender, New York Heart Association functional class and depressive symptoms are the most consistent variables explaining the variance in HRQoL in patients with congestive heart failure. These findings are partly in line with previous research on predictors for hard endpoints in patients with congestive heart failure.

  12. No trade-off between learning speed and associative flexibility in bumblebees: a reversal learning test with multiple colonies.

    Directory of Open Access Journals (Sweden)

    Nigel E Raine

    Full Text Available Potential trade-offs between learning speed and memory-related performance could be important factors in the evolution of learning. Here, we test whether rapid learning interferes with the acquisition of new information using a reversal learning paradigm. Bumblebees (Bombus terrestris were trained to associate yellow with a floral reward. Subsequently the association between colour and reward was reversed, meaning bees then had to learn to visit blue flowers. We demonstrate that individuals that were fast to learn yellow as a predictor of reward were also quick to reverse this association. Furthermore, overnight memory retention tests suggest that faster learning individuals are also better at retaining previously learned information. There is also an effect of relatedness: colonies whose workers were fast to learn the association between yellow and reward also reversed this association rapidly. These results are inconsistent with a trade-off between learning speed and the reversal of a previously made association. On the contrary, they suggest that differences in learning performance and cognitive (behavioural flexibility could reflect more general differences in colony learning ability. Hence, this study provides additional evidence to support the idea that rapid learning and behavioural flexibility have adaptive value.

  13. Adaptive memory: animacy effects persist in paired-associate learning.

    Science.gov (United States)

    VanArsdall, Joshua E; Nairne, James S; Pandeirada, Josefa N S; Cogdill, Mindi

    2015-01-01

    Recent evidence suggests that animate stimuli are remembered better than matched inanimate stimuli. Two experiments tested whether this animacy effect persists in paired-associate learning of foreign words. Experiment 1 randomly paired Swahili words with matched animate and inanimate English words. Participants were told simply to learn the English "translations" for a later test. Replicating earlier findings using free recall, a strong animacy advantage was found in this cued-recall task. Concerned that the effect might be due to enhanced accessibility of the individual responses (e.g., animates represent a more accessible category), Experiment 2 selected animate and inanimate English words from two more constrained categories (four-legged animals and furniture). Once again, an advantage was found for pairs using animate targets. These results argue against organisational accounts of the animacy effect and potentially have implications for foreign language vocabulary learning.

  14. The Adult Learning Open University Determinants (ALOUD) study: Biological and psychological factors associated with learning performance in adult distance education

    NARCIS (Netherlands)

    Neroni, Joyce; Gijselaers, Jérôme; Kirschner, Paul A.; De Groot, Renate

    2017-01-01

    Learning is crucial for everyone. The association between biological (eg, sleep, nutrition) and psychological factors (eg, test anxiety, goal orientation) and learning performance has been well established for children, adolescents and college students in traditional education. Evidence for these

  15. Cerebellar associative sensory learning defects in five mouse autism models

    Science.gov (United States)

    Kloth, Alexander D; Badura, Aleksandra; Li, Amy; Cherskov, Adriana; Connolly, Sara G; Giovannucci, Andrea; Bangash, M Ali; Grasselli, Giorgio; Peñagarikano, Olga; Piochon, Claire; Tsai, Peter T; Geschwind, Daniel H; Hansel, Christian; Sahin, Mustafa; Takumi, Toru; Worley, Paul F; Wang, Samuel S-H

    2015-01-01

    Sensory integration difficulties have been reported in autism, but their underlying brain-circuit mechanisms are underexplored. Using five autism-related mouse models, Shank3+/ΔC, Mecp2R308/Y, Cntnap2−/−, L7-Tsc1 (L7/Pcp2Cre::Tsc1flox/+), and patDp(15q11-13)/+, we report specific perturbations in delay eyeblink conditioning, a form of associative sensory learning requiring cerebellar plasticity. By distinguishing perturbations in the probability and characteristics of learned responses, we found that probability was reduced in Cntnap2−/−, patDp(15q11-13)/+, and L7/Pcp2Cre::Tsc1flox/+, which are associated with Purkinje-cell/deep-nuclear gene expression, along with Shank3+/ΔC. Amplitudes were smaller in L7/Pcp2Cre::Tsc1flox/+ as well as Shank3+/ΔC and Mecp2R308/Y, which are associated with granule cell pathway expression. Shank3+/ΔC and Mecp2R308/Y also showed aberrant response timing and reduced Purkinje-cell dendritic spine density. Overall, our observations are potentially accounted for by defects in instructed learning in the olivocerebellar loop and response representation in the granule cell pathway. Our findings indicate that defects in associative temporal binding of sensory events are widespread in autism mouse models. DOI: http://dx.doi.org/10.7554/eLife.06085.001 PMID:26158416

  16. Implicit versus explicit associative learning and experimentally induced placebo hypoalgesia

    Directory of Open Access Journals (Sweden)

    Andrea L Martin-Pichora

    2011-03-01

    Full Text Available Andrea L Martin-Pichora1,2, Tsipora D. Mankovsky-Arnold3, Joel Katz11Department of Psychology, York University, Toronto, ON, Canada; 2Centre for Student Development and Counseling, Ryerson University, Toronto, ON, Canada; 3Department of Psychology, McGill University, Montreal, QC, CanadaAbstract: The present study examined whether 1 placebo hypoalgesia can be generated through implicit associative learning (ie, conditioning in the absence of conscious awareness and 2 the magnitude of placebo hypoalgesia changes when expectations about pain are made explicit. The temperature of heat pain stimuli was surreptitiously lowered during conditioning trials for the placebo cream and the magnitude of the placebo effect was assessed during a subsequent set of trials when the temperature was the same for both placebo and control conditions. To assess whether placebo hypoalgesia could be generated from an implicit tactile stimulus, a 2 × 2 design was used with direction of cream application as one factor and verbal information about which cream was being applied as the second factor. A significant placebo effect was observed when participants received verbal information about which cream was being applied but not following implicit conditioning alone. However, 87.5% of those who showed a placebo response as the result of implicit conditioning were able to accurately guess the order of cream application during the final trial, despite a lack of awareness about the sensory manipulation and low confidence in their ratings, suggesting implicit learning in some participants. In summary, implicit associative learning was evident in some participants but it was not sufficient to produce a placebo effect suggesting some level of explicit expectation or cognitive mediation may be necessary. Notably, the placebo response was abolished when expectations were made explicit, suggesting a delicate interplay between attention and expectation.Keywords: placebo hypoalgesia

  17. Can 13C stable isotope analysis uncover essential amino acid provisioning by termite-associated gut microbes?

    Directory of Open Access Journals (Sweden)

    Paul A. Ayayee

    2015-08-01

    Full Text Available Gut-associated microbes of insects are postulated to provide a variety of nutritional functions including provisioning essential amino acids (EAAs. Demonstrations of EAA provisioning in insect-gut microbial systems, nonetheless, are scant. In this study, we investigated whether the eastern subterranean termite Reticulitermes flavipes sourced EAAs from its gut-associated microbiota. δ13CEAA data from termite carcass, termite gut filtrate and dietary (wood samples were determined following 13C stable isotope analysis. Termite carcass samples (−27.0 ± 0.4‰, mean ± s.e. were significantly different from termite gut filtrate samples (−27.53 ± 0.5‰, but not the wood diet (−26.0 ± 0.5‰ (F(2,64 = 6, P < 0.0052. δ13CEAA-offsets between termite samples and diet suggested possible non-dietary EAA input. Predictive modeling identified gut-associated bacteria and fungi, respectively as potential major and minor sources of EAAs in both termite carcass and gut filtrate samples, based on δ13CEAA data of four and three EAAs from representative bacteria, fungi and plant data. The wood diet, however, was classified as fungal rather than plant in origin by the model. This is attributed to fungal infestation of the wood diet in the termite colony. This lowers the confidence with which gut microbes (bacteria and fungi can be attributed with being the source of EAA input to the termite host. Despite this limitation, this study provides tentative data in support of hypothesized EAA provisioning by gut microbes, and also a baseline/framework upon which further work can be carried out to definitively verify this function.

  18. Rapid Plasticity in the Prefrontal Cortex during Affective Associative Learning

    Science.gov (United States)

    Rehbein, Maimu A.; Steinberg, Christian; Wessing, Ida; Pastor, María Carmen; Zwitserlood, Pienie; Keuper, Kati; Junghöfer, Markus

    2014-01-01

    MultiCS conditioning is an affective associative learning paradigm, in which affective categories consist of many similar and complex stimuli. Comparing visual processing before and after learning, recent MultiCS conditioning studies using time-sensitive magnetoencephalography (MEG) revealed enhanced activation of prefrontal cortex (PFC) regions towards emotionally paired versus neutral stimuli already during short-latency processing stages (i.e., 50 to 80 ms after stimulus onset). The present study aimed at showing that this rapid differential activation develops as a function of the acquisition and not the extinction of the emotional meaning associated with affectively paired stimuli. MEG data of a MultiCS conditioning study were analyzed with respect to rapid changes in PFC activation towards aversively (electric shock) paired and unpaired faces that occurred during the learning of stimulus-reinforcer contingencies. Analyses revealed an increased PFC activation towards paired stimuli during 50 to 80 ms already during the acquisition of contingencies, which emerged after a single pairing with the electric shock. Corresponding changes in stimulus valence could be observed in ratings of hedonic valence, although participants did not seem to be aware of contingencies. These results suggest rapid formation and access of emotional stimulus meaning in the PFC as well as a great capacity for adaptive and highly resolving learning in the brain under challenging circumstances. PMID:25333631

  19. Reconciling genetic evolution and the associative learning account of mirror neurons through data-acquisition mechanisms.

    Science.gov (United States)

    Lotem, Arnon; Kolodny, Oren

    2014-04-01

    An associative learning account of mirror neurons should not preclude genetic evolution of its underlying mechanisms. On the contrary, an associative learning framework for cognitive development should seek heritable variation in the learning rules and in the data-acquisition mechanisms that construct associative networks, demonstrating how small genetic modifications of associative elements can give rise to the evolution of complex cognition.

  20. Associative vocabulary learning: development and testing of two paradigms for the (re-) acquisition of action- and object-related words.

    Science.gov (United States)

    Freundlieb, Nils; Ridder, Volker; Dobel, Christian; Enriquez-Geppert, Stefanie; Baumgaertner, Annette; Zwitserlood, Pienie; Gerloff, Christian; Hummel, Friedhelm C; Liuzzi, Gianpiero

    2012-01-01

    Despite a growing number of studies, the neurophysiology of adult vocabulary acquisition is still poorly understood. One reason is that paradigms that can easily be combined with neuroscientfic methods are rare. Here, we tested the efficiency of two paradigms for vocabulary (re-) acquisition, and compared the learning of novel words for actions and objects. Cortical networks involved in adult native-language word processing are widespread, with differences postulated between words for objects and actions. Words and what they stand for are supposed to be grounded in perceptual and sensorimotor brain circuits depending on their meaning. If there are specific brain representations for different word categories, we hypothesized behavioural differences in the learning of action-related and object-related words. Paradigm A, with the learning of novel words for body-related actions spread out over a number of days, revealed fast learning of these new action words, and stable retention up to 4 weeks after training. The single-session Paradigm B employed objects and actions. Performance during acquisition did not differ between action-related and object-related words (time*word category: p = 0.01), but the translation rate was clearly better for object-related (79%) than for action-related words (53%, p = 0.002). Both paradigms yielded robust associative learning of novel action-related words, as previously demonstrated for object-related words. Translation success differed for action- and object-related words, which may indicate different neural mechanisms. The paradigms tested here are well suited to investigate such differences with neuroscientific means. Given the stable retention and minimal requirements for conscious effort, these learning paradigms are promising for vocabulary re-learning in brain-lesioned people. In combination with neuroimaging, neuro-stimulation or pharmacological intervention, they may well advance the understanding of language learning

  1. Foreign language learning difficulties in Italian children: are they associated with other learning difficulties?

    Science.gov (United States)

    Ferrari, Marcella; Palladino, Paola

    2007-01-01

    A group of seventh- and eighth-grade Italian students with low achievement (LA) in learning English as a foreign language (FL) was selected and compared to a group with high achievement (HA) in FL learning. The two groups were matched for age and nonverbal intelligence. Two experiments were conducted to examine the participants' verbal and nonverbal learning skills, such as native language reading accuracy, speed and comprehension, calculation, and attention and self-regulation. Both experiments showed that the LA group seemed at risk for reading comprehension difficulties, but its reading speed and accuracy were within the average range according to Italian norms. The results also excluded the possibility that FL learning difficulties of LA participants could be associated with a deficit in calculation. Furthermore, according to teachers' ratings, children with LA appeared at risk for attention-deficit disorder (ADD). The pattern of learning difficulties of seventh- and eighth-grade participants with LA appeared to be not completely comparable with that of high school students at risk of FL learning difficulties as described in the literature.

  2. Stable mucus-associated bacterial communities in bleached and healthy corals of Porites lobata from the Arabian Seas

    KAUST Repository

    Hadaidi, Ghaida Ali Hassan

    2017-03-31

    Coral reefs are subject to coral bleaching manifested by the loss of endosymbiotic algae from coral host tissue. Besides algae, corals associate with bacteria. In particular, bacteria residing in the surface mucus layer are thought to mediate coral health, but their role in coral bleaching is unknown. We collected mucus from bleached and healthy Porites lobata colonies in the Persian/Arabian Gulf (PAG) and the Red Sea (RS) to investigate bacterial microbiome composition using 16S rRNA gene amplicon sequencing. We found that bacterial community structure was notably similar in bleached and healthy corals, and the most abundant bacterial taxa were identical. However, fine-scale differences in bacterial community composition between the PAG and RS were present and aligned with predicted differences in sulfur- and nitrogen-cycling processes. Based on our data, we argue that bleached corals benefit from the stable composition of mucus bacteria that resemble their healthy coral counterparts and presumably provide a conserved suite of protective functions, but monitoring of post-bleaching survival is needed to further confirm this assumption. Conversely, fine-scale site-specific differences highlight flexibility of the bacterial microbiome that may underlie adjustment to local environmental conditions and contribute to the widespread success of Porites lobata.

  3. First observations of elevated ducts associated with intermittent turbulence in the stable boundary layer over Bosten Lake, China

    Science.gov (United States)

    Sun, Zheng; Ning, Hui; Song, Shihui; Yan, Dongmei

    2016-10-01

    Nocturnal radiative cooling is a main driver for atmospheric duct formation. Within this atmospheric process, the impacts of intermittent turbulence on ducting have seldom been studied. In this paper, we reported two confusing ducting events observed in the early morning in August 2014 over Bosten Lake, China, when a stable boundary layer (SBL) still survived, by using tethered high-resolution GPS radiosondes. Elevated ducts with strong humidity inversions were observed during the balloon ascents but were absent during observations made upon the balloon descents several minutes later. This phenomenon was initially hypothesized to be attributable to turbulence motions in the SBL, and the connection between the turbulence event and the radar duct was examined by the statistical Thorpe method. Turbulence patches were detected from the ascent profiles but not from the descent profiles. The possible reasons for the duct formation and elimination were discussed in detail. The turbulent transport of moisture in the SBL and the advection due to airflows coming from the lake are the most probable reasons for duct formation. In one case, the downward transport of moisture by turbulence mixing within a Kelvin-Helmholtz billow at the top of the low-level jet resulted in duct elimination. In another case, the passage of density currents originating from the lake may have caused the elimination of the duct. Few studies have attempted to associate intermittent turbulence with radar ducts; thus, this work represents a pioneering study into the connection between turbulent events and atmospheric ducts in a SBL.

  4. A Review of the Stable Isotope Bio-geochemistry of the Global Silicon Cycle and Its Associated Trace Elements

    Directory of Open Access Journals (Sweden)

    Jill N. Sutton

    2018-01-01

    Full Text Available Silicon (Si is the second most abundant element in the Earth's crust and is an important nutrient in the ocean. The global Si cycle plays a critical role in regulating primary productivity and carbon cycling on the continents and in the oceans. Development of the analytical tools used to study the sources, sinks, and fluxes of the global Si cycle (e.g., elemental and stable isotope ratio data for Ge, Si, Zn, etc. have recently led to major advances in our understanding of the mechanisms and processes that constrain the cycling of Si in the modern environment and in the past. Here, we provide background on the geochemical tools that are available for studying the Si cycle and highlight our current understanding of the marine, freshwater and terrestrial systems. We place emphasis on the geochemistry (e.g., Al/Si, Ge/Si, Zn/Si, δ13C, δ15N, δ18O, δ30Si of dissolved and biogenic Si, present case studies, such as the Silicic Acid Leakage Hypothesis, and discuss challenges associated with the development of these environmental proxies for the global Si cycle. We also discuss how each system within the global Si cycle might change over time (i.e., sources, sinks, and processes and the potential technical and conceptual limitations that need to be considered for future studies.

  5. Deciphering mirror neurons: rational decision versus associative learning.

    Science.gov (United States)

    Khalil, Elias L

    2014-04-01

    The rational-decision approach is superior to the associative-learning approach of Cook et al. at explaining why mirror neurons fire or do not fire - even when the stimulus is the same. The rational-decision approach is superior because it starts with the analysis of the intention of the organism, that is, with the identification of the specific objective or goal that the organism is trying to maximize.

  6. Stable isotopes

    International Nuclear Information System (INIS)

    Evans, D.K.

    1986-01-01

    Seventy-five percent of the world's stable isotope supply comes from one producer, Oak Ridge Nuclear Laboratory (ORNL) in the US. Canadian concern is that foreign needs will be met only after domestic needs, thus creating a shortage of stable isotopes in Canada. This article describes the present situation in Canada (availability and cost) of stable isotopes, the isotope enrichment techniques, and related research programs at Chalk River Nuclear Laboratories (CRNL)

  7. Finding Influential Users in Social Media Using Association Rule Learning

    Directory of Open Access Journals (Sweden)

    Fredrik Erlandsson

    2016-04-01

    Full Text Available Influential users play an important role in online social networks since users tend to have an impact on one other. Therefore, the proposed work analyzes users and their behavior in order to identify influential users and predict user participation. Normally, the success of a social media site is dependent on the activity level of the participating users. For both online social networking sites and individual users, it is of interest to find out if a topic will be interesting or not. In this article, we propose association learning to detect relationships between users. In order to verify the findings, several experiments were executed based on social network analysis, in which the most influential users identified from association rule learning were compared to the results from Degree Centrality and Page Rank Centrality. The results clearly indicate that it is possible to identify the most influential users using association rule learning. In addition, the results also indicate a lower execution time compared to state-of-the-art methods.

  8. Broadening the phenotype of DFNB28: Mutations in TRIOBP are associated with moderate, stable hereditary hearing impairment.

    Science.gov (United States)

    Wesdorp, Mieke; van de Kamp, Jiddeke M; Hensen, Erik F; Schraders, Margit; Oostrik, Jaap; Yntema, Helger G; Feenstra, Ilse; Admiraal, Ronald J C; Kunst, Henricus P M; Tekin, Mustafa; Kanaan, Moien; Kremer, Hannie; Pennings, Ronald J E

    2017-04-01

    DFNB28 is characterized by prelingual, severe to profound sensorineural hearing impairment (HI). It is associated with mutations in exon 6 and 7 of TRIOBP and has not been reported in the European population. Here, we describe two isolated cases of Dutch origin with congenital, moderate HI and compound heterozygous mutations in TRIOBP. Three of the mutations are novel, one nonsense mutation (c.5014G>T (p.Gly1672*)) and two frameshift mutations (c.2653del (p.Arg885Alafs*120) and c.3460_3461del (p.Leu1154Alafs*29)). The fourth mutation is the known c.3232dup (p.Arg1078Profs*6) mutation. Longitudinal audiometric analyses in one of the subjects revealed that HI was stable over a period of 15 years. Vestibular function was normal. Predicted effects of the mutations do not explain the relatively mild phenotype in the presented subjects, whereas location of the mutation might well contribute to the milder HI in one of the subjects. It is known that isoform classes TRIOBP-4 and TRIOBP-5 are important for stereocilia stability and rigidity. To our knowledge, p.Gly1672* is the first pathogenic variant identified in DFNB28 that does not affect isoform class TRIOBP-4. This suggests that a single TRIOBP copy to encode wildtype TRIOBP-4 is insufficient for normal hearing, and that at least one TRIOBP copy to encode TRIOBP-5 is indispensable for normal inner ear function. Furthermore, this study demonstrates that DFNB28 can be milder than reported so far and that mutations in TRIOBP are thus associated with a heterogeneous phenotype. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Genetic dissection of memory for associative and non-associative learning in Caenorhabditis elegans.

    Science.gov (United States)

    Lau, H L; Timbers, T A; Mahmoud, R; Rankin, C H

    2013-03-01

    The distinction between non-associative and associative forms of learning has historically been based on the behavioral training paradigm. Through discovering the molecular mechanisms that mediate learning, we can develop a deeper understanding of the relationships between different forms of learning. Here, we genetically dissect short- and long-term memory for a non-associative form of learning, habituation and an associative form of learning, context conditioning for habituation, in the nematode Caenorhabditis elegans. In short-term chemosensory context conditioning for habituation, worms trained and tested in the presence of either a taste (sodium acetate) or smell (diacetyl) context cue show greater retention of habituation to tap stimuli when compared with animals trained and tested without a salient cue. Long-term memory for olfactory context conditioning was observed 24 h after a training procedure that does not normally induce 24 h memory. Like long-term habituation, this long-term memory was dependent on the transcription factor cyclic AMP-response element-binding protein. Worms with mutations in glr-1 [a non-N-methyl-d-aspartate (NMDA)-type glutamate receptor subunit] showed short-term but not long-term habituation or short- or long-term context conditioning. Worms with mutations in nmr-1 (an NMDA-receptor subunit) showed normal short- and long-term memory for habituation but did not show either short- or long-term context conditioning. Rescue of nmr-1 in the RIM interneurons rescued short- and long-term olfactory context conditioning leading to the hypothesis that these interneurons function to integrate information from chemosensory and mechanosensory systems for associative learning. © 2012 The Authors. Genes, Brain and Behavior © 2012 Blackwell Publishing Ltd and International Behavioural and Neural Genetics Society.

  10. Fear conditioning with film clips: a complex associative learning paradigm.

    Science.gov (United States)

    Kunze, Anna E; Arntz, Arnoud; Kindt, Merel

    2015-06-01

    We argue that the stimuli used in traditional fear conditioning paradigms are too simple to model the learning and unlearning of complex fear memories. We therefore developed and tested an adapted fear conditioning paradigm, specifically designed for the study of complex associative memories. Second, we explored whether manipulating the meaning and complexity of the CS-UCS association strengthened the learned fear association. In a two-day differential fear conditioning study, participants were randomly assigned to two experimental conditions. All participants were subjected to the same CSs (i.e., pictures) and UCS (i.e., 3 s film clip) during fear conditioning. However, in one of the conditions (negative-relevant context), the reinforced CS and UCS were meaningfully connected to each other by a 12 min aversive film clip presented prior to fear acquisition. Participants in the other condition (neutral context) were not able to make such meaningful connection between these stimuli, as they viewed a neutral film clip. Fear learning and unlearning were observed on fear-potentiated startle data and distress ratings within the adapted paradigm. Moreover, several group differences on these measures indicated increased UCS valence and enhanced associative memory strength in the negative-relevant context condition compared to the neutral context condition. Due to technical equipment failure, skin conductance data could not be interpreted. The fear conditioning paradigm as presented in the negative-relevant context condition holds considerable promise for the study of complex associative fear memories and therapeutic interventions for such memories. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Stable Breathing in Patients With Obstructive Sleep Apnea Is Associated With Increased Effort but Not Lowered Metabolic Rate.

    Science.gov (United States)

    de Melo, Camila M; Taranto-Montemurro, Luigi; Butler, James P; White, David P; Loring, Stephen H; Azarbarzin, Ali; Marques, Melania; Berger, Philip J; Wellman, Andrew; Sands, Scott A

    2017-10-01

    In principle, if metabolic rate were to fall during sleep in a patient with obstructive sleep apnea (OSA), ventilatory requirements could be met without increased respiratory effort thereby favoring stable breathing. Indeed, most patients achieve periods of stable flow-limited breathing without respiratory events for periods during the night for reasons that are unclear. Thus, we tested the hypothesis that in patients with OSA, periods of stable breathing occur when metabolic rate (VO2) declines. Twelve OSA patients (apnea-hypopnea index >15 events/h) completed overnight polysomnography including measurements of VO2 (using ventilation and intranasal PO2) and respiratory effort (esophageal pressure). Contrary to our hypothesis, VO2 did not differ between stable and unstable breathing periods in non-REM stage 2 (208 ± 20 vs. 213 ± 18 mL/min), despite elevated respiratory effort during stable breathing (26 ± 2 versus 23 ± 2 cmH2O, p = .03). However, VO2 was lowered during deeper sleep (244 to 179 mL/min from non-REM stages 1 to 3, p = .04) in conjunction with more stable breathing. Further analysis revealed that airflow obstruction curtailed metabolism in both stable and unstable periods, since CPAP increased VO2 by 14% in both cases (p = .02, .03, respectively). Patients whose VO2 fell most during sleep avoided an increase in PCO2 and respiratory effort. OSA patients typically convert from unstable to stable breathing without lowering metabolic rate. During sleep, OSA patients labor with increased respiratory effort but fail to satisfy metabolic demand even in the absence of overt respiratory events. © Sleep Research Society 2017. Published by Oxford University Press on behalf of the Sleep Research Society. All rights reserved. For permissions, please e-mail journals.permissions@oup.com.

  12. Mini-review: Prediction errors, attention and associative learning.

    Science.gov (United States)

    Holland, Peter C; Schiffino, Felipe L

    2016-05-01

    Most modern theories of associative learning emphasize a critical role for prediction error (PE, the difference between received and expected events). One class of theories, exemplified by the Rescorla-Wagner (1972) model, asserts that PE determines the effectiveness of the reinforcer or unconditioned stimulus (US): surprising reinforcers are more effective than expected ones. A second class, represented by the Pearce-Hall (1980) model, argues that PE determines the associability of conditioned stimuli (CSs), the rate at which they may enter into new learning: the surprising delivery or omission of a reinforcer enhances subsequent processing of the CSs that were present when PE was induced. In this mini-review we describe evidence, mostly from our laboratory, for PE-induced changes in the associability of both CSs and USs, and the brain systems involved in the coding, storage and retrieval of these altered associability values. This evidence favors a number of modifications to behavioral models of how PE influences event processing, and suggests the involvement of widespread brain systems in animals' responses to PE. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Age-related changes in contextual associative learning.

    Science.gov (United States)

    Luu, Trinh T; Pirogovsky, Eva; Gilbert, Paul E

    2008-01-01

    The hippocampus plays a critical role in processing contextual information. Although age-related changes in the hippocampus are well documented in humans, nonhuman primates, and rodents, few studies have examined contextual learning deficits in old rats. The present study investigated age-related differences in contextual associative learning in young (6 mo) and old (24 mo) rats using olfactory stimuli. Stimuli consisted of common odors mixed in sand and placed in clear plastic cups. Testing was conducted in two boxes that represented two different contexts (Context 1 and Context 2). The contexts varied based on environmental features of the box such as color (black vs. white), visual cues on the walls of the box, and flooring texture. Each rat was simultaneously presented with two cups, one filled with Odor A and one filled with Odor B in each context. In Context 1, the rat received a food reward for digging in the cup containing Odor A, but did not receive a food reward for digging in the cup containing Odor B. In Context 2, the rat was rewarded for digging in the cup containing Odor B, but did receive a reward for digging in the cup containing Odor A. Therefore, the rat learned to associate Context 1 with Odor A and Context 2 with Odor B. The rat was tested for eight days using the same odor problem throughout all days of testing. The results showed no significant difference between young and old rats on the first two days of testing; however, young rats significantly outperformed old rats on Day 3. Young rats continued to maintain superior performance compared to old rats on Days 4-8. The results suggest that aging results in functional impairments in brain regions that support memory for associations between specific cues and their respective context.

  14. Conservative versus invasive stable ischemic heart disease management strategies: what do we plan to learn from the ISCHEMIA trial?

    Science.gov (United States)

    Cheng-Torres, Kathleen A; Desai, Karan P; Sidhu, Mandeep S; Maron, David J; Boden, William E

    2016-01-01

    Over the past decade, landmark randomized clinical trials comparing initial management strategies in stable ischemic heart disease (SIHD) have demonstrated no significant reduction in 'hard' end points (all-cause mortality, cardiac death or myocardial infarction) with one strategy versus another. The main advantage derived from early revascularization is improved short-term quality of life. Nonetheless, questions remain regarding how best to manage SIHD patients, such as whether a high-risk subgroup can be identified that may experience a survival or myocardial infarction benefit from early revascularization, and if not, when should diagnostic catheterization and revascularization be performed. The International Study of Comparative Health Effectiveness with Medical and Invasive Approaches trial is designed to address these questions by randomizing SIHD patients with at least moderate ischemia to an initial conservative strategy of optimal medical therapy or an initial invasive strategy of optimal medical therapy plus cardiac catheterization and revascularization.

  15. Stable angina pectoris with no obstructive coronary artery disease is associated with increased risks of major adverse cardiovascular events

    DEFF Research Database (Denmark)

    Jespersen, L.; Hvelplund, A.; Abildstrom, S. Z.

    2012-01-01

    Aims Patients with chest pain and no obstructive coronary artery disease (CAD) are considered at low risk for cardiovascular events but evidence supporting this is scarce. We investigated the prognostic implications of stable angina pectoris in relation to the presence and degree of CAD with no o...... with stable angina and normal coronary arteries or diffuse non-obstructive CAD have elevated risks of MACE and all-cause mortality compared with a reference population without ischaemic heart disease.......Aims Patients with chest pain and no obstructive coronary artery disease (CAD) are considered at low risk for cardiovascular events but evidence supporting this is scarce. We investigated the prognostic implications of stable angina pectoris in relation to the presence and degree of CAD...... (MACE), defined as cardiovascular death, myocardial infarction, stroke or heart failure, and all-cause mortality. Significantly more women (65%) than men (32%) had no obstructive CAD (P

  16. Pregnancy associated plasma protein-A as a marker for myocardial infarction and death in patients with stable coronary artery disease: A prognostic study within the CLARICOR Trial

    DEFF Research Database (Denmark)

    Iversen, Kasper K; Teisner, Børge; Winkel, Per

    2011-01-01

    OBJECTIVE: Pregnancy associated plasma protein-A (PAPP-A) is a potential new marker for vulnerable plaques in the coronary arteries only examined in stable coronary disease (CAD) in patients undergoing coronary angiography. Here we address the prognostic value of serum PAPP-A in unselected stable...... outcomes were all-cause mortality and myocardial infarction. RESULTS: Patients (n=4243) were followed for a median of 2.8 years. In a Cox analysis, elevated PAPP-A was significantly related to the composite outcome of myocardial infarction and death (HR 1.99, 95% CI 1.62-2.45, p...

  17. The Adult Learning Open University Determinants (ALOUD) Study: Biological and Psychological Factors Associated with Learning Performance in Adult Distance Education

    Science.gov (United States)

    Neroni, Joyce; Gijselaers, Hieronymus J. M.; Kirschner, Paul A.; Groot, Renate H. M.

    2015-01-01

    Learning is crucial for everyone. The association between biological (eg, sleep, nutrition) and psychological factors (eg, test anxiety, goal orientation) and learning performance has been well established for children, adolescents and college students in traditional education. Evidence for these associations for adult distance students is lacking…

  18. Tempered stable distributions stochastic models for multiscale processes

    CERN Document Server

    Grabchak, Michael

    2015-01-01

    This brief is concerned with tempered stable distributions and their associated Levy processes. It is a good text for researchers interested in learning about tempered stable distributions.  A tempered stable distribution is one which takes a stable distribution and modifies its tails to make them lighter. The motivation for this class comes from the fact that infinite variance stable distributions appear to provide a good fit to data in a variety of situations, but the extremely heavy tails of these models are not realistic for most real world applications. The idea of using distributions that modify the tails of stable models to make them lighter seems to have originated in the influential paper of Mantegna and Stanley (1994). Since then, these distributions have been extended and generalized in a variety of ways. They have been applied to a wide variety of areas including mathematical finance, biostatistics,computer science, and physics.

  19. Carbon Stable Isotope Values in Plankton and Mussels Reflect Changes in Carbonate Chemistry Associated with Nutrient Enhanced Net Production

    Directory of Open Access Journals (Sweden)

    Autumn Oczkowski

    2018-02-01

    Full Text Available Coastal ecosystems are inherently complex and potentially adaptive as they respond to changes in nutrient loads and climate. We documented the role that carbon stable isotope (δ13C measurements could play in understanding that adaptation with a series of three Ecostat (i.e., continuous culture experiments. We quantified linkages among δ13C, nutrients, carbonate chemistry, primary, and secondary production in temperate estuarine waters. Experimental culture vessels (9.1 L containing 33% whole and 67% filtered (0.2 μm seawater were amended with dissolved inorganic nitrogen (N and phosphorous (P in low (3 vessels; 5 μM N, 0.3 μM P, moderate (3 vessels; 25 μM N, 1.6 μM P, and high amounts (3 vessels; 50 μM N, 3.1 μM P. The parameters necessary to calculate carbonate chemistry, chlorophyll-a concentrations, and particulate δ13C values were measured throughout the 14 day experiments. Outflow lines from the experimental vessels fed 250 ml containers seeded with juvenile blue mussels (Mytilus edulis. Mussel subsamples were harvested on days 0, 7, and 14 and their tissues were analyzed for δ13C values. We consistently observed that particulate δ13C values were positively correlated with chlorophyll-a, carbonate chemistry, and to changes in the ratio of bicarbonate to dissolved carbon dioxide (HCO3-:CO2. While the relative proportion of HCO3- to CO2 increased over the 14 days, concentrations of each declined, reflecting the drawdown of carbon associated with enhanced production. Plankton δ13C values, like chlorophyll-a concentrations, increased over the course of each experiment, with the greatest increases in the moderate and high treatments. Trends in δ13C over time were also observed in the mussel tissues. Despite ecological variability and different plankton abundances the experiments consistently demonstrated how δ13C values in primary producers and consumers reflected nutrient availability, via its impact on carbonate chemistry. We

  20. Carbon Stable Isotope Values in Plankton and Mussels Reflect Changes in Carbonate Chemistry Associated with Nutrient Enhanced Net Production

    Science.gov (United States)

    Coastal ecosystems are inherently complex and potentially adaptive as they respond to changes in nutrient loads and climate. We documented the role that carbon stable isotope (δ13C) measurements could play in understanding that adaptation with a series of three Ecostat (i.e...

  1. Substrate properties of stable fly (Diptera: Muscidae) developmental sites associated with round bale hay feeding sites in eastern Nebraska.

    Science.gov (United States)

    Wienhold, B J; Taylor, D B

    2012-04-01

    Residues at sites where stationary feeders were used to provide hay as supplemental forage for cattle during the winter are developmental substrates for immature stable flies, Stomoxys calcitrans (L.), in the central United States. Spatial patterns in physical (substrate depth, temperature, water content), chemical (pH, electrical conductivity [EC(lab)], total nitrogen [N] and carbon [C], ammoniacal nitrogen [NH(4)-N], extractable phosphorus [P]), and biological (microbial respiration rate) substrate properties for two feeding sites were estimated and the correlations between these properties and adult emergence were characterized. Hay feeding sites had a circular footprint with residues extending ≈7 m from the feeder. With the exception of extractable P and total N, all substrate properties exhibited spatial patterns centered on the feeder location. Adult stable fly emergence densities were significantly correlated with substrate microbial respiration rate, NH(4)-N concentration, EC(lab), total C concentration, pH, and moisture content. Logistic regression indicated that EC best predicted the probability of stable flies emerging from a substrate and that the other properties did not provide additional information. A better understanding of the physical, chemical, and biological conditions needed for stable fly larval development may help in identifying previously unrecognized developmental habitats and management of this pest. Targeted implementation of management practices such as sanitation and chemical treatments can be applied to smaller areas reducing labor and improving cost effectiveness.

  2. Prediction and uncertainty in associative learning: examining controlled and automatic components of learned attentional biases.

    Science.gov (United States)

    Luque, David; Vadillo, Miguel A; Le Pelley, Mike E; Beesley, Tom

    2017-08-01

    It has been suggested that attention is guided by two factors that operate during associative learning: a predictiveness principle, by which attention is allocated to the best predictors of outcomes, and an uncertainty principle, by which attention is allocated to learn about the less known features of the environment. Recent studies have shown that predictiveness-driven attention can operate rapidly and in an automatic way to exploit known relationships. The corresponding characteristics of uncertainty-driven attention, on the other hand, remain unexplored. In two experiments we examined whether both predictiveness and uncertainty modulate attentional processing in an adaptation of the dot probe task. This task provides a measure of automatic orientation to cues during associative learning. The stimulus onset asynchrony of the probe display was manipulated in order to explore temporal characteristics of predictiveness- and uncertainty-driven attentional effects. Results showed that the predictive status of cues determined selective attention, with faster attentional capture to predictive than to non-predictive cues. In contrast, the level of uncertainty slowed down responses to the probe regardless of the predictive status of the cues. Both predictiveness- and uncertainty-driven attentional effects were very rapid (at 250 ms from cue onset) and were automatically activated.

  3. Increased circulating follicular regulatory T cells are associated with lower auto-antibodies in stable remission rheumatoid arthritis patients.

    Science.gov (United States)

    Liu, Chen; Wang, Dongwei; Lu, Songsong; Xu, Qinzhu; Zhao, Lei; Zhao, Jingzhong; Song, Ying; Wang, Hui

    2018-01-30

    To examine expression and function changes of circulating CD4 + CXCR5 + FoxP3 + Follicular regulatory T (TFR) cells in active and stable remission rheumatoid arthritis (RA) patients and to clarify the role of TFR cells in the pathogenesis of RA. TFR and follicular helper T cells (TFH) levels in peripheral blood of 39 active RA patients, 39 stable remission RA patients and 33 healthy controls were detected by flow cytometry. The function of TFR cells was measured by co-culturing with TFH and B cells. The activated CD45RA - FoxP3 hi TFR cells were analyzed as well. Clinical indicators including serum levels of Ig and auto-antibodies were tested and correlations with TFR cells were systematically analyzed. DAS28 scores were further calculated and correlation analysis with TFR was conducted as well. The level of CD4 + CXCR5 + FOXP3 + TFR cells and the ratio of TFR/TFH in peripheral blood of stable remission RA patients were significantly increased compared with active RA patients and healthy controls. The function of TFR was enhanced and the activated CD45RA - FoxP3 hi TFR subset was increased in stable remission RA patients compared with healthy controls. Furthermore, TFR cells in RA patients were inversely correlated with Ig G, RF, anti-CCP, as well as DAS28 scores. Circulating TFR cells were increased as RA patients develop to a stable state and increased TFR cells could suppress autoimmunity of RA patients to stabilize their condition. Our results provide novel insight into the pathogenesis process of RA. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  4. Word, nonword and visual paired associate learning in Dutch dyslexic children

    NARCIS (Netherlands)

    Messbauer, V.C.S.; de Jong, P.F.

    2003-01-01

    Verbal and non-verbal learning were investigated in 21 8-11-year-old dyslexic children and chronological-age controls, and in 21 7-9-year-old reading-age controls. Tasks involved the paired associate learning of words, nonwords, or symbols with pictures. Both learning and retention of associations

  5. Are tutor behaviors in problem-based learning stable?: a generalizability study of social congruence, expertise and cognitive congruence.

    Science.gov (United States)

    Williams, Judith C; Alwis, W A M; Rotgans, Jerome I

    2011-10-01

    The purpose of this study was to investigate the stability of three distinct tutor behaviors (1) use of subject-matter expertise, (2) social congruence and (3) cognitive congruence, in a problem-based learning (PBL) environment. The data comprised the input from 16,047 different students to a survey of 762 tutors administered in three consecutive semesters. Over the three semesters each tutor taught two of the same course and one different course. A generalizability study was conducted to determine whether the tutor behaviors were generalizable across the three measurement occasions. The results indicate that three semesters are sufficient to make generalizations about all three tutor behaviors. In addition the results show that individual differences between tutors account for the greatest differences in levels of expertise, social congruence and cognitive congruence. The study concludes that tutor behaviors are fairly consistent in PBL and somewhat impervious to change. Implications of these findings for tutor training are discussed.

  6. Perception of collaborative learning in associate degree students in Hong Kong.

    Science.gov (United States)

    Shek, Daniel T L; Shek, Moses M W

    2013-01-01

    Although collaborative learning has been widely researched in Western contexts, no study has been carried out to understand how associate degree students look at collaborative learning in Hong Kong. In this study, perceptions of and attitudes to collaborative learning among associate degree students were studied. A total of 44 associate degree students completed an online questionnaire including measures of perceived benefits and attitudes to collaborative learning, and social-emotional competence. Results showed that there were no significant differences between male and female students on perceived benefits of and attitudes towards collaborative learning. Social-emotional competence was related to perceived benefits of and attitudes to collaborative learning. Attitudes were also related to perceived benefits of collaborative learning. This paper is the first known study looking at the relationships among perceived benefits and attitudes to collaborative learning and social-emotional competence in Chinese associate degree students in different Chinese contexts.

  7. Statin treatment prevents increased cardiovascular and all-cause mortality associated with clarithromycin in patients with stable coronary heart disease

    DEFF Research Database (Denmark)

    Jensen, Gorm B; Hilden, Jørgen; Als-Nielsen, Bodil

    2010-01-01

    In the CLARICOR trial, significantly increased cardiovascular (CV) and all-cause mortality in stable patients with coronary heart disease were observed after a short course of clarithromycin. We report on the impact of statin treatment at entry on the CV and all-cause mortality. The multicenter...... CLARICOR trial randomized patients to oral clarithromycin (500 mg daily; n = 2172) versus matching placebo (daily; n = 2201) for 2 weeks. Patients were followed through public databases. In the 41% patients on statin treatment at entry, no significant effect of clarithromycin was observed on CV (hazard.......0003; statin-clarithromycin interaction P = 0.0029) and all-cause mortality (HR, 1.33; 95% CI, 1.05-1.67; P = 0.016; statin-clarithromycin interaction P = 0.41). Multivariate analysis and 6-year follow up confirmed these results. Concomitant statin treatment in stable patients with coronary heart disease...

  8. The power of associative learning and the ontogeny of optimal behaviour

    Science.gov (United States)

    Enquist, Magnus; Lind, Johan

    2016-01-01

    Behaving efficiently (optimally or near-optimally) is central to animals' adaptation to their environment. Much evolutionary biology assumes, implicitly or explicitly, that optimal behavioural strategies are genetically inherited, yet the behaviour of many animals depends crucially on learning. The question of how learning contributes to optimal behaviour is largely open. Here we propose an associative learning model that can learn optimal behaviour in a wide variety of ecologically relevant circumstances. The model learns through chaining, a term introduced by Skinner to indicate learning of behaviour sequences by linking together shorter sequences or single behaviours. Our model formalizes the concept of conditioned reinforcement (the learning process that underlies chaining) and is closely related to optimization algorithms from machine learning. Our analysis dispels the common belief that associative learning is too limited to produce ‘intelligent’ behaviour such as tool use, social learning, self-control or expectations of the future. Furthermore, the model readily accounts for both instinctual and learned aspects of behaviour, clarifying how genetic evolution and individual learning complement each other, and bridging a long-standing divide between ethology and psychology. We conclude that associative learning, supported by genetic predispositions and including the oft-neglected phenomenon of conditioned reinforcement, may suffice to explain the ontogeny of optimal behaviour in most, if not all, non-human animals. Our results establish associative learning as a more powerful optimizing mechanism than acknowledged by current opinion. PMID:28018662

  9. [The association between iron deficiency and learning disorders in preschoolers].

    Science.gov (United States)

    Gutiérrez Sigler, D; Colomer Revuelta, J; Barona, C; Momparler, P; Colomer Revuelta, C

    1992-01-01

    With the aim preventing future problems of underachievement at school, we studied the possible relationship between learning difficulties and iron deficiency in nursery-school children. To do this, we determined the prevalence of iron deficiency and the prevalence or learning difficulties in the different areas of mental development in a sample of 136 nursery school children coming from the Alaquàs public school (Valencia), aged between four and five years. Their nutritional state and ferric state, socioeconomic and cultural level, and psychomotor development were evaluated. All the children were in a good nutritional state, coming from homogeneous families as regards their socio-cultural level and being divided into two groups as regards their economic situation. The iron deficiency prevalence was 17.6% in stage I (ferritina sérica < 12 ng/l) and 22.8% in stage III (anemia ferropénica). The coefficient for overall development was 85.95, the lowest marks being in the speech area. A positive association (prevalence ratio = 2; IC 95% = 1.1-8.3) between iron deficiency in its III stage and changes in the specific area of analysis and synthesis.

  10. Solution of the comparator theory of associative learning.

    Science.gov (United States)

    Ghirlanda, Stefano; Ibadullayev, Ismet

    2015-04-01

    We derive an analytical solution of the comparator theory of associative learning, as formalized by Stout and Miller (2007). The solution enables us to calculate exactly the predicted responding to stimuli in any experimental design and for any choice of model parameters. We illustrate its utility by calculating the predictions of comparator theory in some paradigmatic designs: acquisition of conditioned responses, compound conditioning, blocking, unovershadowing, and backward blocking. We consider several versions of the theory: first-order comparator theory (close to the original ideas of Miller & Matzel, 1988), second-order comparator theory (Denniston, Savastano, & Miller, 2001), and sometimes-competing retrieval (Stout & Miller, 2007). We show that all versions of comparator theory make a number of surprising predictions, some of which appear hard to reconcile with empirical data. Our solution paves the way for a fuller understanding of the theory and for its empirical evaluation. (c) 2015 APA, all rights reserved).

  11. Honeybee associative learning performance and metabolic stress resilience are positively associated.

    Directory of Open Access Journals (Sweden)

    Gro V Amdam

    2010-03-01

    Full Text Available Social-environmental influences can affect animal cognition and health. Also, human socio-economic status is a covariate factor connecting psychometric test-performance (a measure of cognitive ability, educational achievement, lifetime health, and survival. The complimentary hypothesis, that mechanisms in physiology can explain some covariance between the same traits, is disputed. Possible mechanisms involve metabolic biology affecting integrity and stability of physiological systems during development and ageing. Knowledge of these relationships is incomplete, and underlying processes are challenging to reveal in people. Model animals, however, can provide insights into connections between metabolic biology and physiological stability that may aid efforts to reduce human health and longevity disparities.We document a positive correlation between a measure of associative learning performance and the metabolic stress resilience of honeybees. This relationship is independent of social factors, and may provide basic insights into how central nervous system (CNS function and metabolic biology can be associated. Controlling for social environment, age, and learning motivation in each bee, we establish that learning in Pavlovian conditioning to an odour is positively correlated with individual survival time in hyperoxia. Hyperoxia induces oxidative metabolic damage, and provides a measure of metabolic stress resistance that is often related to overall lifespan in laboratory animals. The positive relationship between Pavlovian learning ability and stress resilience in the bee is not equally established in other model organisms so far, and contrasts with a genetic cost of improved associative learning found in Drosophila melanogaster.Similarities in the performances of different animals need not reflect common functional principles. A correlation of honeybee Pavlovian learning and metabolic stress resilience, thereby, is not evidence of a shared biology

  12. Learning to Associate Orientation with Color in Early Visual Areas by Associative Decoded fMRI Neurofeedback.

    Science.gov (United States)

    Amano, Kaoru; Shibata, Kazuhisa; Kawato, Mitsuo; Sasaki, Yuka; Watanabe, Takeo

    2016-07-25

    Associative learning is an essential brain process where the contingency of different items increases after training. Associative learning has been found to occur in many brain regions [1-4]. However, there is no clear evidence that associative learning of visual features occurs in early visual areas, although a number of studies have indicated that learning of a single visual feature (perceptual learning) involves early visual areas [5-8]. Here, via decoded fMRI neurofeedback termed "DecNef" [9], we tested whether associative learning of orientation and color can be created in early visual areas. During 3 days of training, DecNef induced fMRI signal patterns that corresponded to a specific target color (red) mostly in early visual areas while a vertical achromatic grating was physically presented to participants. As a result, participants came to perceive "red" significantly more frequently than "green" in an achromatic vertical grating. This effect was also observed 3-5 months after the training. These results suggest that long-term associative learning of two different visual features such as orientation and color was created, most likely in early visual areas. This newly extended technique that induces associative learning is called "A-DecNef," and it may be used as an important tool for understanding and modifying brain functions because associations are fundamental and ubiquitous functions in the brain. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. You see what you have learned. Evidence for an interrelation of associative learning and visual selective attention.

    Science.gov (United States)

    Feldmann-Wüstefeld, Tobias; Uengoer, Metin; Schubö, Anna

    2015-11-01

    Besides visual salience and observers' current intention, prior learning experience may influence deployment of visual attention. Associative learning models postulate that observers pay more attention to stimuli previously experienced as reliable predictors of specific outcomes. To investigate the impact of learning experience on deployment of attention, we combined an associative learning task with a visual search task and measured event-related potentials of the EEG as neural markers of attention deployment. In the learning task, participants categorized stimuli varying in color/shape with only one dimension being predictive of category membership. In the search task, participants searched a shape target while disregarding irrelevant color distractors. Behavioral results showed that color distractors impaired performance to a greater degree when color rather than shape was predictive in the learning task. Neurophysiological results show that the amplified distraction was due to differential attention deployment (N2pc). Experiment 2 showed that when color was predictive for learning, color distractors captured more attention in the search task (ND component) and more suppression of color distractor was required (PD component). The present results thus demonstrate that priority in visual attention is biased toward predictive stimuli, which allows learning experience to shape selection. We also show that learning experience can overrule strong top-down control (blocked tasks, Experiment 3) and that learning experience has a longer-term effect on attention deployment (tasks on two successive days, Experiment 4). © 2015 Society for Psychophysiological Research.

  14. Stable particles

    International Nuclear Information System (INIS)

    Samios, N.P.

    1994-01-01

    I have been asked to review the subject of stable particles, essentially the particles that eventually comprised the meson and baryon octets, with a few more additions - with an emphasis on the contributions made by experiments utilizing the bubble chamber technique. In this activity, much work had been done by the photographic emulsion technique and cloud chambers - exposed to cosmic rays as well as accelerator based beams. In fact, many if not most of the stable particles were found by these latter two techniques, however, the foree of the bubble chamber (coupled with the newer and more powerful accelerators) was to verify, and reinforce with large statistics, the existence of these states, to find some of the more difficult ones, mainly neutrals and further to elucidate their properties, i.e., spin, parity, lifetimes, decay parameters, etc. (orig.)

  15. Stable particles

    International Nuclear Information System (INIS)

    Samios, N.P.

    1993-01-01

    I have been asked to review the subject of stable particles, essentially the particles that eventually comprised the meson and baryon octets. with a few more additions -- with an emphasis on the contributions made by experiments utilizing the bubble chamber technique. In this activity, much work had been done by the photographic emulsion technique and cloud chambers-exposed to cosmic rays as well as accelerator based beams. In fact, many if not most of the stable particles were found by these latter two techniques, however, the forte of the bubble chamber (coupled with the newer and more powerful accelerators) was to verify, and reinforce with large statistics, the existence of these states, to find some of the more difficult ones, mainly neutrals and further to elucidate their properties, i.e., spin, parity, lifetimes, decay parameters, etc

  16. High relative abundance of the stable fly Stomoxys calcitrans is associated with lumpy skin disease outbreaks in Israeli dairy farms.

    Science.gov (United States)

    Kahana-Sutin, E; Klement, E; Lensky, I; Gottlieb, Y

    2017-06-01

    The vector of lumpy skin disease (LSD), a viral disease affecting Bovidae, is currently unknown. To evaluate the possible vector of LSD virus (LSDV) under field conditions, a yearlong trapping of dipterans was conducted in dairy farms that had been affected by LSD, 1-2 years previously. This was done in order to calculate monthly relative abundances of each dipteran in each farm throughout the year. The relative abundances of Stomoxys calcitrans (Diptera: Muscidae) in the months parallel to the outbreaks (December and April) were significantly higher than those of other dipterans. A stable fly population model based on weather parameters for the affected area was used to validate these findings. Its results were significantly correlated with S. calcitrans abundance. This model, based on weather parameters during the epidemic years showed that S. calcitrans populations peaked in the months of LSD onset in the studied farms. These observations and model predictions revealed a lower abundance of stable flies during October and November, when LSD affected adjacent grazing beef herds. These findings therefore suggest that S. calcitrans is a potential vector of LSD in dairy farms and that another vector is probably involved in LSDV transmission in grazing herds. These findings should be followed up with vector competence studies. © 2016 The Royal Entomological Society.

  17. Assessment of the effects of cage fish-farming on damselfish-associated food chains using stable-isotope analyses

    International Nuclear Information System (INIS)

    Jan, Rong-Quen; Kao, Shuh-Ji; Dai, Chang-Feng; Ho, Cheng-Tze

    2014-01-01

    Highlights: • Damselfishes living at sites near a cage farm bore lower δ 13 C and higher δ 15 N. • Similar trends occurred in zooplankton and detritus, major foods for damselfishes. • δ 15 N enrichment in fish may have arisen from the uptake of excess feed and prey. • Farm wastes were documented entering the ecosystem through the pelagic food chain. • No clear evidence of the effects of cage farming on stable isotopes in macroalgae. - Abstract: To assess the effect of cage fish-farming on the coral reef ecosystem off Xiaoliuchiu Island, southern Taiwan, geographical differences in the food chain of each of two damselfishes, Pomacentrus vaiuli and Chromis margaritifer, were examined using a stable-isotope approach. For each damselfish, individuals were found to consume similar foods at all sites. However, specimens collected at sites near the cage farm (as the experimental sites) exhibited lower δ 13 C and higher δ 15 N signatures compared to those from reference sites. Similar trends also occurred in the zooplankton and detritus, two major food sources for both damselfishes. This finding indicates that particulate organic matter released by the farm may have entered the coral reef ecosystem through the pelagic food chain. Artificial reef emplacement is recommended to provide extra habitats under cage farms to support additional pelagic-feeding fish populations, thereby reducing environmental impacts of cage farming on coral reefs

  18. Effect of Phonetic Association on Learning Vocabulary in Foreign Language

    Science.gov (United States)

    Bozavli, Ebubekir

    2017-01-01

    Word is one of the most important components of a natural language. Speech is meaningful because of the meanings of words. Vocabulary acquired in one's mother tongue is learned consciously in a foreign language in non-native settings. Learning vocabulary in a system based on grammar is generally neglected or learned in conventional ways. This…

  19. Challenges Associated with Teaching and Learning of English ...

    African Journals Online (AJOL)

    Nekky Umera

    structures. Challenges in the Teaching and Learning of Grammar. Learners' errors and deviant forms in the use of English are a major challenge in the teaching and learning of English in Nigerian. Secondary Schools. However, Kisparsky (1972) Akinbode (2006) have classified errors in second language learning into two.

  20. Stable beams

    CERN Multimedia

    2015-01-01

    Stable beams: two simple words that carry so much meaning at CERN. When LHC page one switched from "squeeze" to "stable beams" at 10.40 a.m. on Wednesday, 3 June, it triggered scenes of jubilation in control rooms around the CERN sites, as the LHC experiments started to record physics data for the first time in 27 months. This is what CERN is here for, and it’s great to be back in business after such a long period of preparation for the next stage in the LHC adventure.   I’ve said it before, but I’ll say it again. This was a great achievement, and testimony to the hard and dedicated work of so many people in the global CERN community. I could start to list the teams that have contributed, but that would be a mistake. Instead, I’d simply like to say that an achievement as impressive as running the LHC – a machine of superlatives in every respect – takes the combined effort and enthusiasm of everyone ...

  1. Subjective learning discounts test type: evidence from an associative learning and transfer task.

    Science.gov (United States)

    Touron, Dayna R; Hertzog, Christopher; Speagle, James Z

    2010-01-01

    We evaluated the extent to which memory test format and test transfer influence the dynamics of metacognitive judgments. Participants completed two study-test phases for paired-associates, with or without transferring test type, in one of four conditions: (1) recognition then recall, (2) recall then recognition, (3) recognition throughout, or (4) recall throughout. Global judgments were made prestudy, poststudy, and posttest for each phase; judgments of learning (JOLs) following item study were also collected. Results suggest that metacognitive judgment accuracy varies substantially by memory test type. Whereas underconfidence in JOLs and global predictions increases with recall practice (Koriat's underconfidence-with-practice effect), underconfidence decreases with recognition practice. Moreover, performance changes when transferring test type were not fully anticipated by pretest judgments.

  2. Factors associated with learning management in Mexican micro-entrepreneurs

    Directory of Open Access Journals (Sweden)

    Alejandro Mungaray Lagarda

    2016-10-01

    Full Text Available The learning capacity of social based Mexican micro-entrepreneurs to generate new knowledge and incorporate it to its products and services is evaluated. The above is done through a confirmatory factor analysis and structural linear equation system, and the presence of static and dynamic dimensions in learning capacity, which are represented by individual stocks and flows of knowledge. The positive relationship between them demonstrates the presence of learning processes that impact positively their economic performance.

  3. Decreased Expression of Stable RNA Can Alleviate the Lethality Associated with RNase E Deficiency in Escherichia coli.

    Science.gov (United States)

    Himabindu, P; Anupama, K

    2017-04-15

    The endoribonuclease RNase E participates in mRNA degradation, rRNA processing, and tRNA maturation in Escherichia coli , but the precise reasons for its essentiality are unclear and much debated. The enzyme is most active on RNA substrates with a 5'-terminal monophosphate, which is sensed by a domain in the enzyme that includes residue R169; E. coli also possesses a 5'-pyrophosphohydrolase, RppH, that catalyzes conversion of 5'-terminal triphosphate to 5'-terminal monophosphate on RNAs. Although the C-terminal half (CTH), beyond residue approximately 500, of RNase E is dispensable for viability, deletion of the CTH is lethal when combined with an R169Q mutation or with deletion of rppH In this work, we show that both these lethalities can be rescued in derivatives in which four or five of the seven rrn operons in the genome have been deleted. We hypothesize that the reduced stable RNA levels under these conditions minimize the need of RNase E to process them, thereby allowing for its diversion for mRNA degradation. In support of this hypothesis, we have found that other conditions that are known to reduce stable RNA levels also suppress one or both lethalities: (i) alterations in relA and spoT , which are expected to lead to increased basal ppGpp levels; (ii) stringent rpoB mutations, which mimic high intracellular ppGpp levels; and (iii) overexpression of DksA. Lethality suppression by these perturbations was RNase R dependent. Our work therefore suggests that its actions on the various substrates (mRNA, rRNA, and tRNA) jointly contribute to the essentiality of RNase E in E. coli IMPORTANCE The endoribonuclease RNase E is essential for viability in many Gram-negative bacteria, including Escherichia coli Different explanations have been offered for its essentiality, including its roles in global mRNA degradation or in the processing of several tRNA and rRNA species. Our work suggests that, rather than its role in the processing of any one particular substrate, its

  4. Machine Learning Identifies Stemness Features Associated with Oncogenic Dedifferentiation.

    Science.gov (United States)

    Malta, Tathiane M; Sokolov, Artem; Gentles, Andrew J; Burzykowski, Tomasz; Poisson, Laila; Weinstein, John N; Kamińska, Bożena; Huelsken, Joerg; Omberg, Larsson; Gevaert, Olivier; Colaprico, Antonio; Czerwińska, Patrycja; Mazurek, Sylwia; Mishra, Lopa; Heyn, Holger; Krasnitz, Alex; Godwin, Andrew K; Lazar, Alexander J; Stuart, Joshua M; Hoadley, Katherine A; Laird, Peter W; Noushmehr, Houtan; Wiznerowicz, Maciej

    2018-04-05

    Cancer progression involves the gradual loss of a differentiated phenotype and acquisition of progenitor and stem-cell-like features. Here, we provide novel stemness indices for assessing the degree of oncogenic dedifferentiation. We used an innovative one-class logistic regression (OCLR) machine-learning algorithm to extract transcriptomic and epigenetic feature sets derived from non-transformed pluripotent stem cells and their differentiated progeny. Using OCLR, we were able to identify previously undiscovered biological mechanisms associated with the dedifferentiated oncogenic state. Analyses of the tumor microenvironment revealed unanticipated correlation of cancer stemness with immune checkpoint expression and infiltrating immune cells. We found that the dedifferentiated oncogenic phenotype was generally most prominent in metastatic tumors. Application of our stemness indices to single-cell data revealed patterns of intra-tumor molecular heterogeneity. Finally, the indices allowed for the identification of novel targets and possible targeted therapies aimed at tumor differentiation. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

  5. Associative and sensorimotor learning for parenting involves mirror neurons under the influence of oxytocin.

    Science.gov (United States)

    Ho, S Shaun; Macdonald, Adam; Swain, James E

    2014-04-01

    Mirror neuron-based associative learning may be understood according to associative learning theories, in addition to sensorimotor learning theories. This is important for a comprehensive understanding of the role of mirror neurons and related hormone modulators, such as oxytocin, in complex social interactions such as among parent-infant dyads and in examples of mirror neuron function that involve abnormal motor systems such as depression.

  6. Associative and sensorimotor learning for parenting involves mirror neurons under the influence of oxytocin

    OpenAIRE

    Ho, S. Shaun; MacDonald, Adam; Swain, James E.

    2014-01-01

    Mirror neuron–based associative learning may be understood according to associative learning theories, in addition to sensorimotor learning theories. This is important for a comprehensive understanding of the role of mirror neurons and related hormone modulators, such as oxytocin, in complex social interactions such as among parent–infant dyads and in examples of mirror neuron function that involve abnormal motor systems such as depression.

  7. Contingencies: Learning Numerical and Emotional Associations in an Uncertain World

    NARCIS (Netherlands)

    B. de Langhe (Bart)

    2011-01-01

    textabstractThe ability to learn about the relation or covariation between events happening in the world is probably the most critical aspect of human cognition. This dissertation examines how the human mind learns numerical and emotional relations and explores consequences for managerial and

  8. Can zebrafish learn spatial tasks? An empirical analysis of place and single CS-US associative learning.

    Science.gov (United States)

    Karnik, Indraneel; Gerlai, Robert

    2012-08-01

    The zebrafish may be an ideal tool with which genes underlying learning and memory can be identified and functionally investigated. From a translational viewpoint, relational learning and episodic memory are particularly important as their impairment is the hallmark of prevalent human neurodegenerative diseases. Recent reports suggest that zebrafish are capable of solving complex relational-type associative learning tasks, namely spatial learning tasks. However, it is not known whether good performance in these tasks was truly based upon relational learning or upon a single CS-US association. Here we study whether zebrafish can find a rewarding stimulus (sight of conspecifics) based upon a single associative cue or/and upon the location of the reward using a method conceptually similar to 'context and cue dependent fear conditioning' employed with rodents. Our results confirm that zebrafish can form an association between a salient visual cue and the rewarding stimulus and at the same time they can also learn where the reward is presented. Although our results do not prove that zebrafish form a dynamic spatial map of their surroundings and use this map to locate their reward, they do show that these fish perform similarly to rodents whose hippocampal function is unimpaired. These results further strengthen the notion that complex cognitive abilities exist in the zebrafish and thus they may be analyzed using the excellent genetic tool set developed for this simple vertebrate. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. Using variability to guide dimensional weighting: Associative mechanisms in early word learning

    Science.gov (United States)

    Apfelbaum, Keith S.; McMurray, Bob

    2013-01-01

    At 14 months, children appear to struggle to apply their fairly well developed speech perception abilities to learning similar sounding words (e.g. bih/dih; Stager & Werker, 1997). However, variability in non-phonetic aspects of the training stimuli seems to aid word learning at this age. Extant theories of early word learning cannot account for this benefit of variability. We offer a simple explanation for this range of effects based on associative learning. Simulations suggest that if infants encode both non-contrastive information (e.g. cues to speaker voice) and meaningful linguistic cues (e.g. place of articulation or voicing), then associative learning mechanisms predict these variability effects in early word learning. Crucially, this means that despite the importance of task variables in predicting performance, this body of work shows that phonological categories are still developing in this age, and that the structure of non-informative cues has critical influences on word learning abilities. PMID:21609356

  10. Stable cystatin C serum levels confirm normal renal function in patients with dronedarone-associated increase in serum creatinine.

    Science.gov (United States)

    Duncker, David; Oswald, Hanno; Gardiwal, Ajmal; Lüsebrink, Ulrich; König, Thorben; Schreyer, Hendrik; Klein, Gunnar

    2013-03-01

    Dronedarone is a new antiarrhythmic drug for patients with nonpermanent atrial fibrillation (AF). A relatively consistent finding in all trials studying dronedarone was a moderate but significant elevation of serum creatinine. Since dronedarone competes for the same organic cation transporter in the distal renal tubule with creatinine, serum creatinine and its derived estimated glomerular filtration rate might not reflect true renal function in patients on dronedarone. We therefore investigated alternative markers for renal function in these patients. We prospectively included 20 patients with nonpermanent AF in whom dronedarone 400 mg twice daily was started. Patients had normal renal function and serum creatinine; serum cystatin C and creatinine clearance were measured before treatment and 10 and 90 days after treatment started. Mean serum creatinine level for all 20 patients at baseline (day 0) was 84.55 ± 12.14 and 87.8 ± 17.59 µmol/L on day 10. This slight increase in all patients was not significant. Patients were now divided into the predefined groups of "increased creatinine" (increase in serum creatinine level > 1 standard deviation) and "not increased creatinine." Patients with increased creatinine levels (n = 5) showed a significant elevation of serum creatinine levels from day 0 to day 10 (82.4 ± 9.18 to 104.4 ± 12.74 µmol/L; P = .003), whereas change in serum creatinine levels in the not increased creatinine group (n = 15) was not significant. Serum cystatin C levels remained stable in both of these groups (increased creatinine group: 0.76 ± 0.08 to 0.78 ± 0.08 mg/L; P = .65; not increased creatinine group: 0.77 ± 0.108 to 0.77 ± 0.107 mg/L; P = .906). In conclusion, cystatin C represents an easily available and reliable biomarker for estimation of true renal function in patients on dronedarone treatment.

  11. The Association between Students' Style of Learning Preferences, Social Presence, Collaborative Learning and Learning Outcomes

    Science.gov (United States)

    Chen, Clement; Jones, Keith T.; Xu, Shawn

    2018-01-01

    Differences in styles of learning have become important considerations at all levels of education over the last several years. Examining college students' preferred style of learning is useful for course design and effective instructional methods. Using the Felder-Silverman Index of Learning Styles (ILS), we investigate how students' styles of…

  12. The stable subgroup graph

    Directory of Open Access Journals (Sweden)

    Behnaz Tolue

    2018-07-01

    Full Text Available In this paper we introduce stable subgroup graph associated to the group $G$. It is a graph with vertex set all subgroups of $G$ and two distinct subgroups $H_1$ and $H_2$ are adjacent if $St_{G}(H_1\\cap H_2\

  13. The effects of aging on the neural basis of implicit associative learning in a probabilistic triplets learning task.

    Science.gov (United States)

    Simon, Jessica R; Vaidya, Chandan J; Howard, James H; Howard, Darlene V

    2012-02-01

    Few studies have investigated how aging influences the neural basis of implicit associative learning, and available evidence is inconclusive. One emerging behavioral pattern is that age differences increase with practice, perhaps reflecting the involvement of different brain regions with training. Many studies report hippocampal involvement early on with learning becoming increasingly dependent on the caudate with practice. We tested the hypothesis that the contribution of these regions to learning changes with age because of differential age-related declines in the striatum and hippocampi. We assessed age-related differences in brain activation during implicit associative learning using the Triplets Learning Task. Over three event-related fMRI runs, 11 younger and 12 healthy older adults responded to only the third (target) stimulus in sequences of three stimuli ("triplets") by corresponding key press. Unbeknown to participants, the first stimulus' location predicted one target location for 80% of trials and another target location for 20% of trials. Both age groups learned associative regularities but differences in favor of the younger adults emerged with practice. The neural basis of learning (response to predictability) was examined by identifying regions that showed a greater response to triplets that occurred more frequently. Both age groups recruited the hippocampus early, but with training, the younger adults recruited their caudate whereas the older adults continued to rely on their hippocampus. This pattern enables older adults to maintain near-young levels of performance early in training, but not later, and adds to evidence that implicit associative learning is supported by different brain networks in younger and older adults.

  14. Stable nitrogen isotope ratios of macrophytes and associated periphyton along a nitrate gradient in two subtropical, spring-fed streams

    DEFF Research Database (Denmark)

    De Brabandere, Loreto; Frazer, Thomas K.; Montoya, Joseph P.

    2007-01-01

    1. An increase in human population and associated changes in land use have caused an increase in groundwater nitrate concentrations throughout central Florida. Within the region, this nitrate-laden groundwater returns to the surface via numerous large springs that serve as the origin of flow for ...

  15. Easy to Learn, Hard to Suppress: The Impact of Learned Stimulus-Outcome Associations on Subsequent Action Control

    Science.gov (United States)

    Van Wouwe, N.C.; van den Wildenberg, W.P.M.; Ridderinkhof, K. R.; Claassen, D.O.; Neimat, J.S.; Wylie, S.A.

    2015-01-01

    The inhibition of impulsive response tendencies that conflict with goal-directed action is a key component of executive control. An emerging literature reveals that the proficiency of inhibitory control is modulated by expected or unexpected opportunities to earn reward or avoid punishment. However, less is known about how inhibitory control is impacted by the processing of task-irrelevant stimulus information that has been associated previously with particular outcomes (reward or punishment) or response tendencies (action or inaction). We hypothesized that stimulus features associated with particular action-valence tendencies, even though task irrelevant, would modulate inhibitory control processes. Participants first learned associations between stimulus features (color), actions, and outcomes using an action-valence learning task that orthogonalizes action (action, inaction) and valence (reward, punishment). Next, these stimulus features were embedded in a Simon task as a task-irrelevant stimulus attribute. We analyzed the effects of action-valence associations on the Simon task by means of distributional analysis to reveal the temporal dynamics. Learning patterns replicated previously reported biases; inherent, Pavlovian-like mappings (action-reward, inaction-punishment avoidance) were easier to learn than mappings conflicting with these biases (action-punishment avoidance, inaction-reward). More importantly, results from two experiments demonstrated that the easier to learn, Pavlovian-like action-valence associations interfered with the proficiency of inhibiting impulsive actions in the Simon task. Processing conflicting associations led to more proficient inhibitory control of impulsive actions, similar to Simon trials without any association. Fast impulsive errors were reduced for trials associated with punishment in comparison to reward trials or trials without any valence association. These findings provide insight into the temporal dynamics of task

  16. Multivoxel Object Representations in Adult Human Visual Cortex Are Flexible: An Associative Learning Study.

    Science.gov (United States)

    Senoussi, Mehdi; Berry, Isabelle; VanRullen, Rufin; Reddy, Leila

    2016-06-01

    Learning associations between co-occurring events enables us to extract structure from our environment. Medial-temporal lobe structures are critical for associative learning. However, the role of the ventral visual pathway (VVP) in associative learning is not clear. Do multivoxel object representations in the VVP reflect newly formed associations? We show that VVP multivoxel representations become more similar to each other after human participants learn arbitrary new associations between pairs of unrelated objects (faces, houses, cars, chairs). Participants were scanned before and after 15 days of associative learning. To evaluate how object representations changed, a classifier was trained on discriminating two nonassociated categories (e.g., faces/houses) and tested on discriminating their paired associates (e.g., cars/chairs). Because the associations were arbitrary and counterbalanced across participants, there was initially no particular reason for this cross-classification decision to tend toward either alternative. Nonetheless, after learning, cross-classification performance increased in the VVP (but not hippocampus), on average by 3.3%, with some voxels showing increases of up to 10%. For example, a chair multivoxel representation that initially resembled neither face nor house representations was, after learning, classified as more similar to that of faces for participants who associated chairs with faces and to that of houses for participants who associated chairs with houses. Additionally, learning produced long-lasting perceptual consequences. In a behavioral priming experiment performed several months later, the change in cross-classification performance was correlated with the degree of priming. Thus, VVP multivoxel representations are not static but become more similar to each other after associative learning.

  17. Synthesis, Physical Properties and Reactivity of Stable Antiaromatic 1,4-DIHYDROPYRAZINES and Their Associated Radical Cations

    Science.gov (United States)

    Brook, David James Rawsthorne

    Self condensation of 3-(chloromethyl)-5,6-dihydro -5,5-dimethyl oxazin-2-one and 3-(chloromethyl)-5,6-dihydro -1,5, 5-trimethylpyrazin-2-one gave the 1,4-dihydropyrazines, 4a,8a-diaza-2,6-dioxa-3,4,7,8-tetrahydro- 4,4,8,8 -tetramethylanthracene-1,5,-dione (DDTTA), and 2,4,4,6,8,8-hexamethyl-2,4a,6,8a-tetraaza - 3,4,7,8-tetrahydroanthracene-1,5-dione (HTTA), respectively. Extension of this reaction to other systems resulted in failure. Thionation of DDTTA with phosphorus pentasulphide in pyridine gave mono and dithiono ester derivatives. The dihydropyrazine rings of these systems were planar and showed long wavelength pi-pi^* electronic absorption resulting in the compounds being coloured. The long wavelength band showed significant solvatochromism. NMR measurements indicated that the rings are also paratropic. DDTTA, HTTA and the thiones all showed reversible one electron oxidation to the radical cation which was characterised by electron spin resonance spectroscopy. HTTA and DDTTA also showed reversible oxidation of the radical cation to the dication. Hydrogenation of DDTTA resulted in a tetrahydropyrazine derivative, 4a,8a-diaza-2,6-dioxa -3,4,7,8,9,9a-hexahydro- 4,4,8,8-tetramethylanthracene -1,5-dione (4.5), which underwent atmospheric oxidation back to DDTTA and the alcohol 4a,8a-diaza-2,6-dioxa-3,4,7,8,9,9a -hexahydro-9a-hydroxy- 4,4,8,8-tetramethylanthracene -1,5-dione (4.6). The HTTA analogue 2,4,4,6,8,8-hexamethyl -3,4,7,8,9,9a-hexahydro- 2,4a,6,8a-tetraazaanthracene -1,5-dione (4.9) is stable under the same conditions. The difference in behaviour was explained as a result of the captodative effect. DDTTA was found to undergo rapid (2 + 2) cycloaddition to the dienophile, 4-phenyl-1,2,4-triazoline -3,5-dione (PTAD). Reaction of DDTTA with ^ {3}O_{2} was found to be solvent dependent. In acetic acid the dioxetane 4a,8a-diaza-2,6-dioxa-9,9a-epidioxy-3,4,7,8,9,9a -hexahydro- 4,4,8,8-tetramethylanthracene -1,5-dione was observed; whereas, in acetonitrile

  18. Reduced autobiographical memory specificity is associated with impaired discrimination learning in anxiety disorder patients

    Science.gov (United States)

    Lenaert, Bert; Boddez, Yannick; Vervliet, Bram; Schruers, Koen; Hermans, Dirk

    2015-01-01

    Associative learning plays an important role in the development of anxiety disorders, but a thorough understanding of the variables that impact such learning is still lacking. We investigated whether individual differences in autobiographical memory specificity are related to discrimination learning and generalization. In an associative learning task, participants learned the association between two pictures of female faces and a non-aversive outcome. Subsequently, six morphed pictures functioning as generalization stimuli (GSs) were introduced. In a sample of healthy participants (Study 1), we did not find evidence for differences in discrimination learning as a function of memory specificity. In a sample of anxiety disorder patients (Study 2), individuals who were characterized by low memory specificity showed deficient discrimination learning relative to high specific individuals. In contrast to previous findings, results revealed no effect of memory specificity on generalization. These results indicate that impaired discrimination learning, previously shown in patients suffering from an anxiety disorder, may be—in part—due to limited memory specificity. Together, these studies emphasize the importance of incorporating cognitive variables in associative learning theories and their implications for the development of anxiety disorders. In addition, re-analyses of the data (Study 3) showed that patients suffering from panic disorder showed higher outcome expectancies in the presence of the stimulus that was never followed by an outcome during discrimination training, relative to patients suffering from other anxiety disorders and healthy participants. Because we used a neutral, non-aversive outcome (i.e., drawing of a lightning bolt), these data suggest that learning abnormalities in panic disorder may not be restricted to fear learning, but rather reflect a more general associative learning deficit that also manifests in fear irrelevant contexts. PMID

  19. Reduced autobiographical memory specificity is associated with impaired discrimination learning in anxiety disorder patients

    Directory of Open Access Journals (Sweden)

    Bert eLenaert

    2015-07-01

    Full Text Available Associative learning plays an important role in the development of anxiety disorders, but a thorough understanding of the variables that impact such learning is still lacking. We investigated whether individual differences in autobiographical memory specificity are related to discrimination learning and generalization. In an associative learning task, participants learned the association between two pictures of female faces and a non-aversive outcome. Subsequently, six morphed pictures functioning as generalization stimuli (GSs were introduced. In a sample of healthy participants (Study 1, we did not find evidence for differences in discrimination learning as a function of memory specificity. In a sample of anxiety disorder patients (Study 2, individuals who were characterized by low memory specificity showed deficient discrimination learning relative to high specific individuals. In contrast to previous findings, results revealed no effect of memory specificity on generalization. These results indicate that impaired discrimination learning, previously shown in patients suffering from an anxiety disorder, may be – in part – due to limited memory specificity. Together, these studies emphasize the importance of incorporating cognitive variables in associative learning theories and their implications for the development of anxiety disorders. In addition, re-analyses of the data (Study 3 showed that patients suffering from panic disorder showed higher outcome expectancies in the presence of the stimulus that was never followed by an outcome during discrimination training, relative to patients suffering from other anxiety disorders and healthy participants. Because we used a neutral, non-aversive outcome (i.e., drawing of a lightning bolt, these data suggest that learning abnormalities in panic disorder may not be restricted to fear learning, but rather reflect a more general associative learning deficit that also manifests in fear irrelevant

  20. Attention Cueing and Activity Equally Reduce False Alarm Rate in Visual-Auditory Associative Learning through Improving Memory.

    Science.gov (United States)

    Nikouei Mahani, Mohammad-Ali; Haghgoo, Hojjat Allah; Azizi, Solmaz; Nili Ahmadabadi, Majid

    2016-01-01

    In our daily life, we continually exploit already learned multisensory associations and form new ones when facing novel situations. Improving our associative learning results in higher cognitive capabilities. We experimentally and computationally studied the learning performance of healthy subjects in a visual-auditory sensory associative learning task across active learning, attention cueing learning, and passive learning modes. According to our results, the learning mode had no significant effect on learning association of congruent pairs. In addition, subjects' performance in learning congruent samples was not correlated with their vigilance score. Nevertheless, vigilance score was significantly correlated with the learning performance of the non-congruent pairs. Moreover, in the last block of the passive learning mode, subjects significantly made more mistakes in taking non-congruent pairs as associated and consciously reported lower confidence. These results indicate that attention and activity equally enhanced visual-auditory associative learning for non-congruent pairs, while false alarm rate in the passive learning mode did not decrease after the second block. We investigated the cause of higher false alarm rate in the passive learning mode by using a computational model, composed of a reinforcement learning module and a memory-decay module. The results suggest that the higher rate of memory decay is the source of making more mistakes and reporting lower confidence in non-congruent pairs in the passive learning mode.

  1. Use of the Learning together technique associated to the theory of significative learning

    Directory of Open Access Journals (Sweden)

    Ester López Donoso

    2008-09-01

    Full Text Available This article deals with an experimental research, regarding a qualitative and quantitative design, applied to a group of students of General Physics course during the first semester of the university career of Engineering. Historically, students of this course present learning difficulties that directly affect their performance, conceptualization and permanence in the university. The present methodology integrates the collaborative learning, denominated Learning Together", with the theory of significant learning to avoid the above-written difficulties. Results of this research show that the proposed methodology works properly, especially to improve the conceptualization.

  2. Visual and olfactory associative learning in the malaria vector Anopheles gambiae sensu stricto

    Directory of Open Access Journals (Sweden)

    Chilaka Nora

    2012-01-01

    Full Text Available Abstract Background Memory and learning are critical aspects of the ecology of insect vectors of human pathogens because of their potential effects on contacts between vectors and their hosts. Despite this epidemiological importance, there have been only a limited number of studies investigating associative learning in insect vector species and none on Anopheline mosquitoes. Methods A simple behavioural assays was developed to study visual and olfactory associative learning in Anopheles gambiae, the main vector of malaria in Africa. Two contrasted membrane qualities or levels of blood palatability were used as reinforcing stimuli for bi-directional conditioning during blood feeding. Results Under such experimental conditions An. gambiae females learned very rapidly to associate visual (chequered and white patterns and olfactory cues (presence and absence of cheese or Citronella smell with the reinforcing stimuli (bloodmeal quality and remembered the association for up to three days. Associative learning significantly increased with the strength of the conditioning stimuli used. Importantly, learning sometimes occurred faster when a positive reinforcing stimulus (palatable blood was associated with an innately preferred cue (such as a darker visual pattern. However, the use of too attractive a cue (e.g. Shropshire cheese smell was counter-productive and decreased learning success. Conclusions The results address an important knowledge gap in mosquito ecology and emphasize the role of associative memory for An. gambiae's host finding and blood-feeding behaviour with important potential implications for vector control.

  3. Stable Host Gene Expression in the Gut of Adult Drosophila melanogaster with Different Bacterial Mono-Associations

    Science.gov (United States)

    Zhang, Vivian; Ludington, William B.; Eisen, Michael B.

    2016-01-01

    There is growing evidence that the microbes found in the digestive tracts of animals influence host biology, but we still do not understand how they accomplish this. Here, we evaluated how different microbial species commonly associated with laboratory-reared Drosophila melanogaster impact host biology at the level of gene expression in the dissected adult gut and in the entire adult organism. We observed that guts from animals associated from the embryonic stage with either zero, one or three bacterial species demonstrated indistinguishable transcriptional profiles. Additionally, we found that the gut transcriptional profiles of animals reared in the presence of the yeast Saccharomyces cerevisiae alone or in combination with bacteria could recapitulate those of conventionally-reared animals. In contrast, we found whole body transcriptional profiles of conventionally-reared animals were distinct from all of the treatments tested. Our data suggest that adult flies are insensitive to the ingestion of the bacteria found in their gut, but that prior to adulthood, different microbes impact the host in ways that lead to global transcriptional differences observable across the whole adult body. PMID:27898741

  4. Does academic performance or personal growth share a stronger association with learning environment perception?

    OpenAIRE

    Colbert-Getz, Jorie M.; Tackett, Sean; Wright, Scott M.; Shochet, Robert S.

    2016-01-01

    Objectives This study was conducted to characterize the relative strength of associations of learning environment perception with academic performance and with personal growth. Methods In 2012-2014 second and third year students at Johns Hopkins University School of Medicine completed a learning environment survey and personal growth scale. Hierarchical linear regression analysis was employed to determine if the proportion of variance in learning environment scores accounted for by personal g...

  5. Object associations of early-learned light and heavy English verbs.

    Science.gov (United States)

    Maouene, Josita; Laakso, Aarre; Smith, Linda B

    2011-02-01

    Many of the verbs that young children learn early have been characterized as 'light.' However, there is no agreed upon definition of 'lightness' and no useable metric that could be applied to a wide array of verbs. This article provides evidence for one metric by which the 'lightness' of early-learned verbs might be measured: the number of objects with which they are associated (in adult judgment) or co-occur (in speech to and by children). The results suggest that early-learned light verbs and heavy verbs differ in the breadth of the objects they are associated with: light verbs have weak associations with specific objects, whereas heavy verbs are strongly associated with specific objects. However, there is an indication that verbs have narrower associations to objects in speech to children. The methodological usefulness of this metric is discussed as are the implications of the patterns of distributions for children's learning of common verbs.

  6. [Association between self-directed learning behaviors, socio-demographic and academic variables among medical students].

    Science.gov (United States)

    Fasce H, Eduardo; Ortega B, Javiera; Pérez V, Cristhian; Márquez U, Carolina; Parra P, Paula; Ortiz M, Liliana; Matus, Olga

    2013-09-01

    Medical education must encourage autonomous learning behaviors among students. However the great income profile disparity among university students may influence their capacity to acquire such skills. To assess the association between self-directed learning, socio-demographic and academic variables. The self-directed learning readiness scale was applied to 202 medical students aged between 17 and 25 years (64% males). Simultaneously information about each surveyed participant was obtained from the databases of the medical school. There is an association between socio-demographic and academic variables with the general scale of self-directed learning and the subscales learning planning and willingness to learn. Participants coming from municipal schools have a greater willingness to learn than their counterparts coming from subsidized and private schools. High school grades are related to self-directed learning and the subscales learning planning and self-assessment. Among the surveyed medical students, there is a relationship between self-directed learning behaviors, the type of school where they come from and the grades that they obtained during high school.

  7. Active Learning "Not" Associated with Student Learning in a Random Sample of College Biology Courses

    Science.gov (United States)

    Andrews, T. M.; Leonard, M. J.; Colgrove, C. A.; Kalinowski, S. T.

    2011-01-01

    Previous research has suggested that adding active learning to traditional college science lectures substantially improves student learning. However, this research predominantly studied courses taught by science education researchers, who are likely to have exceptional teaching expertise. The present study investigated introductory biology courses…

  8. Probabilistic Category Learning in Developmental Dyslexia: Evidence from Feedback and Paired-Associate Weather Prediction Tasks

    Science.gov (United States)

    Gabay, Yafit; Vakil, Eli; Schiff, Rachel; Holt, Lori L.

    2015-01-01

    Objective Developmental dyslexia is presumed to arise from specific phonological impairments. However, an emerging theoretical framework suggests that phonological impairments may be symptoms stemming from an underlying dysfunction of procedural learning. Method We tested procedural learning in adults with dyslexia (n=15) and matched-controls (n=15) using two versions of the Weather Prediction Task: Feedback (FB) and Paired-associate (PA). In the FB-based task, participants learned associations between cues and outcomes initially by guessing and subsequently through feedback indicating the correctness of response. In the PA-based learning task, participants viewed the cue and its associated outcome simultaneously without overt response or feedback. In both versions, participants trained across 150 trials. Learning was assessed in a subsequent test without presentation of the outcome, or corrective feedback. Results The Dyslexia group exhibited impaired learning compared with the Control group on both the FB and PA versions of the weather prediction task. Conclusions The results indicate that the ability to learn by feedback is not selectively impaired in dyslexia. Rather it seems that the probabilistic nature of the task, shared by the FB and PA versions of the weather prediction task, hampers learning in those with dyslexia. Results are discussed in light of procedural learning impairments among participants with dyslexia. PMID:25730732

  9. The study of associative learning: mapping from psychological to neural levels of analysis.

    Science.gov (United States)

    Delamater, Andrew R; Lattal, K Matthew

    2014-02-01

    One of the major achievements of the last century of research in experimental psychology is the identification of a coherent set of theories and principles to characterize the nature of simple forms of associative learning. Major advances are also currently being made at a rapid pace in the neurobiology of associative learning, and, interestingly, we are beginning to see how a mapping from a psychological level of analysis to underlying neurobiological mechanisms is possible. This collection of papers honors the illustrative careers of four major learning theorists from the experimental psychology tradition (Robert Rescorla, Allan Wagner, Nicholas Mackintosh, Anthony Dickinson) who have helped shape our understanding of behavioral principles. The collection of works in this special issue reflects common interests among researchers working at both psychological and neurobiological levels of analysis towards a more comprehensive understanding of basic associative learning processes as they relate to several key issues identified and intensively studied by these influential learning theorists. These consist of the questions regarding (1) the critical conditions enabling learning, (2) the contents of learning, and (3) the rules that translate learning into performance. In one way or another, the separate contributions in this issue address these fundamental questions as they relate to a wide variety of currently exciting topics in the study of the neurobiology of learning and memory. Copyright © 2013 Elsevier Inc. All rights reserved.

  10. Choline acetyltransferase in the hippocampus is associated with learning strategy preference in adult male rats.

    Science.gov (United States)

    Hawley, Wayne R; Witty, Christine F; Daniel, Jill M; Dohanich, Gary P

    2015-08-01

    One principle of the multiple memory systems hypothesis posits that the hippocampus-based and striatum-based memory systems compete for control over learning. Consistent with this notion, previous research indicates that the cholinergic system of the hippocampus plays a role in modulating the preference for a hippocampus-based place learning strategy over a striatum-based stimulus--response learning strategy. Interestingly, in the hippocampus, greater activity and higher protein levels of choline acetyltransferase (ChAT), the enzyme that synthesizes acetylcholine, are associated with better performance on hippocampus-based learning and memory tasks. With this in mind, the primary aim of the current study was to determine if higher levels of ChAT and the high-affinity choline uptake transporter (CHT) in the hippocampus were associated with a preference for a hippocampus-based place learning strategy on a task that also could be solved by relying on a striatum-based stimulus--response learning strategy. Results confirmed that levels of ChAT in the dorsal region of the hippocampus were associated with a preference for a place learning strategy on a water maze task that could also be solved by adopting a stimulus-response learning strategy. Consistent with previous studies, the current results support the hypothesis that the cholinergic system of the hippocampus plays a role in balancing competition between memory systems that modulate learning strategy preference. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Corrective Surgery for Congenital Scoliosis Associated with Split Cord Malformation: It May Be Safe to Leave Diastematomyelia Untreated in Patients with Intact or Stable Neurological Status.

    Science.gov (United States)

    Shen, Jianxiong; Zhang, Jianguo; Feng, Fan; Wang, Yipeng; Qiu, Guixing; Li, Zheng

    2016-06-01

    The treatment of congenital scoliosis associated with split cord malformation (SCM) raises the issue of how to best manage such patients to avoid neurological deficit while achieving a satisfactory correction. This prospective clinical study was performed at our center from March 2000 through June 2013. We enrolled a total of 214 patients (61 male and 153 female) with congenital scoliosis associated with SCM who were undergoing spinal correction surgery. The mean age at surgery was 14.1 years. The inclusion criteria were congenital scoliosis with confirmed SCM; status as neurologically intact or stable over the preceding 2 years; and no neurological deterioration as evidenced on traction, side-bending, or fulcrum-bending radiographs. Patients with unstable neurological status or for whom vertebral column resection surgery was planned were excluded. All patients underwent scoliosis surgery without prophylactic detethering. On the basis of the Pang classification, 73 patients were in the type-I SCM group, and 141 were in the type-II SCM group. The groups did not differ significantly with respect to preoperative characteristics, operative time, blood loss, or number of levels fused. The mean follow-up was 37 months (range, 24 to 108 months). The rate of scoliosis correction was lower in the type-I group than in the type-II group (p patients experienced transient neurological complications, with no significant difference between the groups (p = 0.415). No patient experienced permanent neurological deficit during surgery or follow-up. Patients with congenital scoliosis associated with SCM, regardless of type, can safely and effectively undergo spinal deformity correction and achieve spinal balance without neurological intervention. For such patients with intact or stable neurological status, prophylactic detethering prior to scoliosis surgery may not be necessary. Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence

  12. Examining the nature of impairment in visual paired associate learning in amnestic mild cognitive impairment.

    Science.gov (United States)

    Harel, Brian T; Darby, David; Pietrzak, Robert H; Ellis, Kathryn A; Snyder, Peter J; Maruff, Paul

    2011-11-01

    Visual spatial learning is impaired in mild cognitive impairment (MCI) although the nature of this impairment is not clear. This study investigated the nature and magnitude of errors made by adults with amnestic MCI (aMCI) when learning pattern-location paired associations in a continuous manner. Visual associate learning was measured using the Continuous Paired Associate Learning (CPAL) task in which 30 adults who met clinical criteria for aMCI and 30 matched controls were required to learn a set of associations between patterns and locations across increasing memory loads (two, four, six, and eight). As hypothesized, the aMCI group made more total errors than controls for all memory loads above two. However, the rate of increase in errors with memory load in the aMCI group was approximately twice that for controls. In controls, errors on the CPAL task reflected almost exclusively difficulty in memory. In the aMCI group, errors on the CPAL reflected limitations in associative learning but also in short-term memory and response monitoring. These results suggest that impairments in specific aspects of executive function and working memory might contribute to poor performance on visual paired associate learning in aMCI.

  13. Depletion of the heaviest stable N isotope is associated with NH4+/NH3 toxicity in NH4+-fed plants

    Directory of Open Access Journals (Sweden)

    Martins-Loução Maria A

    2011-05-01

    transports N in the molecular form and is associated with fractionation and another that transports N in the ionic form and is not associated with fractionation.

  14. University of Central Florida and the American Association of State Colleges and Universities: Blended Learning Toolkit

    Science.gov (United States)

    EDUCAUSE, 2014

    2014-01-01

    The Blended Learning Toolkit supports the course redesign approach, and interest in its openly available clearinghouse of online tools, strategies, curricula, and other materials to support the adoption of blended learning continues to grow. When the resource originally launched in July 2011, 20 AASCU [American Association of State Colleges and…

  15. Effects of Learning Experience on Forgetting Rates of Item and Associative Memories

    Science.gov (United States)

    Yang, Jiongjiong; Zhan, Lexia; Wang, Yingying; Du, Xiaoya; Zhou, Wenxi; Ning, Xueling; Sun, Qing; Moscovitch, Morris

    2016-01-01

    Are associative memories forgotten more quickly than item memories, and does the level of original learning differentially influence forgetting rates? In this study, we addressed these questions by having participants learn single words and word pairs once (Experiment 1), three times (Experiment 2), and six times (Experiment 3) in a massed…

  16. Stable association of a Drosophila-derived microbiota with its animal partner and the nutritional environment throughout a fly population's life cycle.

    Science.gov (United States)

    Téfit, Mélisandre A; Gillet, Benjamin; Joncour, Pauline; Hughes, Sandrine; Leulier, François

    2017-09-12

    In the past years, the fruit fly Drosophila melanogaster has been extensively used to study the relationship between animals and their associated microbes. Compared to the one of wild populations, the microbiota of laboratory-reared flies is less diverse, and comprises fewer bacterial taxa; nevertheless, the main commensal bacteria found in fly microbiota always belong to the Acetobacteraceae and Lactobacillaceae families. The bacterial communities associated with the fly are environmentally acquired, and the partners engage in a perpetual re-association process. Adult flies constantly ingest and excrete microbes from and onto their feeding substrate, which are then transmitted to the next generation developing within this shared habitat. We wanted to analyze the potential changes in the bacterial community during its reciprocal transfer between the two compartments of the niche (i.e. the fly and the diet). To address this question, we used a diverse, wild-derived microbial community and analyzed its relationship with the fly population and the nutritive substrate in a given habitat. Here we show that the community was overall well maintained upon transmission to a new niche, to a new fly population and to their progeny, illustrating the stable association of a Drosophila-derived microbiota with its fly partner and the nutritional environment. These results highlight the preponderant role of the nutritional substrate in the dynamics of Drosophila/microbiota interactions, and the need to fully integrate this variable when performing such studies. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. 9. Challenges Associated with Learning Oral Diagnostic Sciences, A ...

    African Journals Online (AJOL)

    user

    categorize specified challenges of learning ODS in. Nigeria. METHODS. This was a cross sectional survey of undergraduate dental students (UDS) and resident doctors (RDS) in dental surgery in five institutions in Nigeria. (University of Ibadan and the University College. Hospital, University of Lagos and Lagos University.

  18. Greater mindful eating practice is associated with better reversal learning

    NARCIS (Netherlands)

    Janssen, Lieneke K.; Duif, Iris; Loon, Van Ilke; Vries, De Jeanne H.M.; Speckens, Anne E.M.; Cools, Roshan; Aarts, Esther

    2018-01-01

    Mindfulness-based interventions are thought to reduce compulsive behavior such as overeating by promoting behavioral flexibility. Here the main aim was to provide support for mindfulness-mediated improvements in reversal learning, a direct measure of behavioral flexibility. We investigated

  19. Business Models Associated with Distance Learning in Higher Education

    Science.gov (United States)

    Wang, Shouhong; Wang, Hai

    2017-01-01

    Textbook prices are continuously rising in higher education. This paper analyzes a business model which makes commercial textbooks more expensive, and explains why this issue tends to be more severe in the field of distance learning in higher education. It reports a case of adoption of open educational resources (OER) textbook for an online course…

  20. Motivated strategies for learning and their association with academic ...

    African Journals Online (AJOL)

    Students with prior educational experience and those who attended peermentoring sessions had significantly higher learning strategy scores. Significant but moderate relationships were found between academic performance and the motivation strategies subsumed within the categories 'task value' and 'self-efficacy for ...

  1. Unpredictably Stable

    DEFF Research Database (Denmark)

    Failla, Virgilio; Melillo, Francesca; Reichstein, Toke

    is tested on matched employer-employee data from the entire Danish population. The analysis reveals that self-employed stay longer in their employment status compared to individuals in paid-employment. This effect is not explained by reduced attractiveness to the wage sector (lock-in effect). We interpret......Does entrepreneurship lower the losses associated with labor market mismatching by lowering employment turnover? This paper examines whether a transition to self-employment induces a shift into an individual’s stayer-mover tendency. Using a propensity score-matching technique, the hypothesis...

  2. Cortico-hippocampal interaction and adaptive stimulus representation: A neurocomputational theory of associative learning and memory.

    NARCIS (Netherlands)

    Gluck, M.A.; Myers, C.E; Meeter, M.

    2005-01-01

    Computational models of the hippocampal region link psychological theories of associative learning with their underlying physiological and anatomical substrates. Our approach to theory development began with a broad description of the computations that depend on the hippocampal region in classical

  3. A high-capacity model for one shot association learning in the brain

    Directory of Open Access Journals (Sweden)

    Hafsteinn eEinarsson

    2014-11-01

    Full Text Available We present a high-capacity model for one-shot association learning(hetero-associative memory in sparse networks. We assume that basic patternsare pre-learned in networks and associations between two patterns are presentedonly once and have to be learned immediately. The model is a combination of anAmit-Fusi like network sparsely connected to a Willshaw type network. Thelearning procedure is palimpsest and comes from earlier work on one-shotpattern learning. However, in our setup we can enhance the capacity of thenetwork by iterative retrieval. This yields a model for sparse brain-likenetworks in which populations of a few thousand neurons are capable of learninghundreds of associations even if they are presented only once. The analysis ofthe model is based on a novel result by Janson et. al. on bootstrappercolation in random graphs.

  4. Host-dependent differences in resource use associated with Anilocra spp. parasitism in two coral reef fishes, as revealed by stable carbon and nitrogen isotope analyses

    Science.gov (United States)

    Welicky, Rachel; Demopoulos, Amanda W. J.; Sikkel, Paul C.

    2017-01-01

    The role of parasites in trophic ecology is poorly understood in marine ecosystems. Stable isotope analyses (SIA) have been widely used in studies of trophic ecology, but have rarely been applied to study the role of parasites. Considering that some parasites are associated with altered host foraging patterns, SIA can help elucidate whether parasitism influences host trophic interactions. French grunt (Haemulon flavolineatum), an abundant Caribbean coral reef fish, contributes greatly to trophic connectivity. They typically depart the reef at dusk, feed overnight in seagrass beds, and return to the reef at dawn. The large parasitic isopod Anilocra haemuli commonly infects French grunt, and infected fish are less likely to complete their diel migration, and are in poorer condition than uninfected conspecifics. Brown chromis (Chromis multilineata) are diurnally feeding planktivores and infection by Anilocra chromis does not influence host condition. To determine if Anilocra infection influences host diet and foraging locality, we conducted stable carbon and nitrogen isotope analyses on scale, muscle, heart and gill tissues of infected and uninfected French grunt and brown chromis. We determined that all French grunt had δ13C values representative of seagrass habitats, but infected French grunt were significantly enriched in 13C and 15N compared to uninfected conspecifics. This suggests that compared to uninfected conspecifics, infected French grunt forage in seagrass, but on isotopically enriched prey, and/or are in poorer condition, which can elevate δ13C and δ15N values. For brown chromis, infection did not significantly influence any δ13C and δ15N values; hence they all foraged in the same environment and on similar prey. This is the first study to use SIA to examine differences in resource use by Caribbean coral reef fishes associated with parasitism and to evaluate how closely related parasites might have host-dependent effects on host trophic ecology.

  5. BDNF val66met genotype and schizotypal personality traits interact to influence probabilistic association learning.

    Science.gov (United States)

    Skilleter, Ashley Jayne; Weickert, Cynthia Shannon; Moustafa, Ahmed Abdelhalim; Gendy, Rasha; Chan, Mico; Arifin, Nur; Mitchell, Philip Bowden; Weickert, Thomas Wesley

    2014-11-01

    The brain derived neurotrophic factor (BDNF) val66met polymorphism rs6265 influences learning and may represent a risk factor for schizophrenia. Healthy people with high schizotypal personality traits display cognitive deficits that are similar to but not as severe as those observed in schizophrenia and they can be studied without confounds of antipsychotics or chronic illness. How genetic variation in BDNF may impact learning in individuals falling along the schizophrenia spectrum is unknown. We predicted that schizotypal personality traits would influence learning and that schizotypal personality-based differences in learning would vary depending on the BDNF val66met genotype. Eighty-nine healthy adults completed the Schizotypal Personality Questionnaire (SPQ) and a probabilistic association learning test. Blood samples were genotyped for the BDNF val66met polymorphism. An ANOVA was performed with BDNF genotype (val homozygotes and met-carriers) and SPQ score (high/low) as grouping variables and probabilistic association learning as the dependent variable. Participants with low SPQ scores (fewer schizotypal personality traits) showed significantly better learning than those with high SPQ scores. BDNF met-carriers displaying few schizotypal personality traits performed best, whereas BDNF met-carriers displaying high schizotypal personality traits performed worst. Thus, the BDNF val66met polymorphism appears to influence probabilistic association learning differently depending on the extent of schizotypal personality traits displayed. Crown Copyright © 2014. Published by Elsevier B.V. All rights reserved.

  6. The Learning Healthcare System and Cardiovascular Care: A Scientific Statement From the American Heart Association.

    Science.gov (United States)

    Maddox, Thomas M; Albert, Nancy M; Borden, William B; Curtis, Lesley H; Ferguson, T Bruce; Kao, David P; Marcus, Gregory M; Peterson, Eric D; Redberg, Rita; Rumsfeld, John S; Shah, Nilay D; Tcheng, James E

    2017-04-04

    The learning healthcare system uses health information technology and the health data infrastructure to apply scientific evidence at the point of clinical care while simultaneously collecting insights from that care to promote innovation in optimal healthcare delivery and to fuel new scientific discovery. To achieve these goals, the learning healthcare system requires systematic redesign of the current healthcare system, focusing on 4 major domains: science and informatics, patient-clinician partnerships, incentives, and development of a continuous learning culture. This scientific statement provides an overview of how these learning healthcare system domains can be realized in cardiovascular disease care. Current cardiovascular disease care innovations in informatics, data uses, patient engagement, continuous learning culture, and incentives are profiled. In addition, recommendations for next steps for the development of a learning healthcare system in cardiovascular care are presented. © 2017 American Heart Association, Inc.

  7. Early student outcomes associated with a virtual community for learning.

    Science.gov (United States)

    Giddens, Jean Foret; Shuster, Geoff; Roehrig, Nicole

    2010-06-01

    Virtual communities represent a new and innovative approach to learning within nursing education. Because this is an emerging trend, little is known about the use of virtual communities and the impact on students and their learning. This article reports the results of a study designed to assess the initial perceived benefits of using a virtual community known as The Neighborhood in a single undergraduate baccalaureate nursing program during the first few years following development. Results showed greater benefits reported among underrepresented minority students and students who expected to receive lower than a course grade of A. In addition, findings suggest the strength of perceived benefits increases over time among all learners. These findings merely scratch the surface of additional work needed in this area. Copyright 2010, SLACK Incorporated.

  8. Associability-modulated loss learning is increased in posttraumatic stress disorder

    Science.gov (United States)

    Brown, Vanessa M; Zhu, Lusha; Wang, John M; Frueh, B Christopher

    2018-01-01

    Disproportionate reactions to unexpected stimuli in the environment are a cardinal symptom of posttraumatic stress disorder (PTSD). Here, we test whether these heightened responses are associated with disruptions in distinct components of reinforcement learning. Specifically, using functional neuroimaging, a loss-learning task, and a computational model-based approach, we assessed the mechanistic hypothesis that overreactions to stimuli in PTSD arise from anomalous gating of attention during learning (i.e., associability). Behavioral choices of combat-deployed veterans with and without PTSD were fit to a reinforcement learning model, generating trial-by-trial prediction errors (signaling unexpected outcomes) and associability values (signaling attention allocation to the unexpected outcomes). Neural substrates of associability value and behavioral parameter estimates of associability updating, but not prediction error, increased with PTSD during loss learning. Moreover, the interaction of PTSD severity with neural markers of associability value predicted behavioral choices. These results indicate that increased attention-based learning may underlie aspects of PTSD and suggest potential neuromechanistic treatment targets. PMID:29313489

  9. The role of prefrontal dopamine D1 receptors in the neural mechanisms of associative learning.

    Science.gov (United States)

    Puig, M Victoria; Miller, Earl K

    2012-06-07

    Dopamine is thought to play a major role in learning. However, while dopamine D1 receptors (D1Rs) in the prefrontal cortex (PFC) have been shown to modulate working memory-related neural activity, their role in the cellular basis of learning is unknown. We recorded activity from multiple electrodes while injecting the D1R antagonist SCH23390 in the lateral PFC as monkeys learned visuomotor associations. Blocking D1Rs impaired learning of novel associations and decreased cognitive flexibility but spared performance of already familiar associations. This suggests a greater role for prefrontal D1Rs in learning new, rather than performing familiar, associations. There was a corresponding greater decrease in neural selectivity and increase in alpha and beta oscillations in local field potentials for novel than for familiar associations. Our results suggest that weak stimulation of D1Rs observed in aging and psychiatric disorders may impair learning and PFC function by reducing neural selectivity and exacerbating neural oscillations associated with inattention and cognitive deficits. Copyright © 2012 Elsevier Inc. All rights reserved.

  10. The amygdala complex: multiple roles in associative learning and attention.

    OpenAIRE

    Gallagher, M; Holland, P C

    1994-01-01

    Although certain neurophysiological functions of the amygdala complex in learning seem well established, the purpose of this review is to propose that an additional conceptualization of amygdala function is now needed. The research we review provides evidence that a subsystem within the amygdala provides a coordinated regulation of attentional processes. An important aspect of this additional neuropsychology of the amygdala is that it may aid in understanding the importance of connections bet...

  11. IDH mutations are closely associated with mutations of DNMT3A, ASXL1 and SRSF2 in patients with myelodysplastic syndromes and are stable during disease evolution.

    Science.gov (United States)

    Lin, Chien-Chin; Hou, Hsin-An; Chou, Wen-Chien; Kuo, Yuan-Yeh; Liu, Chieh-Yu; Chen, Chien-Yuan; Lai, Yan-Jun; Tseng, Mei-Hsuan; Huang, Chi-Fei; Chiang, Ying-Chieh; Lee, Fen-Yu; Liu, Ming-Chih; Liu, Chia-Wen; Tang, Jih-Luh; Yao, Ming; Huang, Shang-Yi; Ko, Bor-Sheng; Wu, Shang-Ju; Tsay, Woei; Chen, Yao-Chang; Tien, Hwei-Fang

    2014-02-01

    Current information about clinical significance of IDH mutations in myelodysplastic syndromes (MDS), their association with other genetic alterations and the stability during disease progression is limited. In this study, IDH mutations were identified in 4.6% of 477 patients with MDS based on the FAB classification and in 2.2 % of 368 patients based on the 2008 WHO classification. IDH mutations were closely associated with older age, higher platelet counts, and mutations of DNMT3A (36.4% vs. 8.7%, P IDH2 mutation was a poor prognostic factor for overall survival in patients with lower-risk MDS, based on international prognosis scoring system (IPSS), FAB classification, WHO classification, or revised IPSS (all P ≦ 0.001), but not in higher-risk groups. Sequential studies in 151 patients demonstrated that all IDH-mutated patients retained the same mutation during disease evolution while none of the IDH-wild patients acquired a novel mutation during follow-ups. In conclusion, IDH mutation is a useful biomarker for risk stratification of patients with lower-risk MDS. IDH mutations are stable during the clinical course. The mutation, in association with other genetic alterations, may play a role in the development, but not progression of MDS. Copyright © 2013 Wiley Periodicals, Inc.

  12. Psychosocial and Adaptive Deficits Associated With Learning Disability Subtypes.

    Science.gov (United States)

    Backenson, Erica M; Holland, Sara C; Kubas, Hanna A; Fitzer, Kim R; Wilcox, Gabrielle; Carmichael, Jessica A; Fraccaro, Rebecca L; Smith, Amanda D; Macoun, Sarah J; Harrison, Gina L; Hale, James B

    2015-01-01

    Children with specific learning disabilities (SLD) have deficits in the basic psychological processes that interfere with learning and academic achievement, and for some SLD subtypes, these deficits can also lead to emotional and/or behavior problems. This study examined psychosocial functioning in 123 students, aged 6 to 11, who underwent comprehensive evaluations for learning and/or behavior problems in two Pacific Northwest school districts. Using concordance-discordance model (C-DM) processing strengths and weaknesses SLD identification criteria, results revealed working memory SLD (n = 20), processing speed SLD (n = 30), executive SLD (n = 32), and no disability groups (n = 41). Of the SLD subtypes, repeated measures MANOVA results revealed the processing speed SLD subtype exhibited the greatest psychosocial and adaptive impairment according to teacher behavior ratings. Findings suggest processing speed deficits may be behind the cognitive and psychosocial disturbances found in what has been termed "nonverbal" SLD. Limitations, implications, and future research needs are addressed. © Hammill Institute on Disabilities 2013.

  13. Associative learning of odor with food- or blood-meal by Culex quinquefasciatus Say (Diptera: Culicidae)

    Science.gov (United States)

    Tomberlin, Jeffery K.; Rains, Glen C.; Allan, Sandy A.; Sanford, Michelle R.; Lewis, W. Joe

    2006-11-01

    The ability of many insects to learn has been documented. However, a limited number of studies examining associative learning in medically important arthropods has been published. Investigations into the associative learning capabilities of Culex quinquefasciatus Say were conducted by adapting methods commonly used in experiments involving Hymenoptera. Male and female mosquitoes were able to learn a conditioned stimulus that consisted of an odor not normally encountered in nature (synthetic strawberry or vanilla extracts) in association with an unconditioned stimulus consisting of either a sugar (males and females) or blood (females) meal. Such information could lead to a better understanding of the ability of mosquitoes to locate and select host and food resources in nature.

  14. Neuronal representations of stimulus associations develop in the temporal lobe during learning.

    Science.gov (United States)

    Messinger, A; Squire, L R; Zola, S M; Albright, T D

    2001-10-09

    Visual stimuli that are frequently seen together become associated in long-term memory, such that the sight of one stimulus readily brings to mind the thought or image of the other. It has been hypothesized that acquisition of such long-term associative memories proceeds via the strengthening of connections between neurons representing the associated stimuli, such that a neuron initially responding only to one stimulus of an associated pair eventually comes to respond to both. Consistent with this hypothesis, studies have demonstrated that individual neurons in the primate inferior temporal cortex tend to exhibit similar responses to pairs of visual stimuli that have become behaviorally associated. In the present study, we investigated the role of these areas in the formation of conditional visual associations by monitoring the responses of individual neurons during the learning of new stimulus pairs. We found that many neurons in both area TE and perirhinal cortex came to elicit more similar neuronal responses to paired stimuli as learning proceeded. Moreover, these neuronal response changes were learning-dependent and proceeded with an average time course that paralleled learning. This experience-dependent plasticity of sensory representations in the cerebral cortex may underlie the learning of associations between objects.

  15. Learning the association between a context and a target location in infancy.

    Science.gov (United States)

    Bertels, Julie; San Anton, Estibaliz; Gebuis, Titia; Destrebecqz, Arnaud

    2017-07-01

    Extracting the statistical regularities present in the environment is a central learning mechanism in infancy. For instance, infants are able to learn the associations between simultaneously or successively presented visual objects (Fiser & Aslin, ; Kirkham, Slemmer & Johnson, ). The present study extends these results by investigating whether infants can learn the association between a target location and the context in which it is presented. With this aim, we used a visual associative learning procedure inspired by the contextual cuing paradigm, with infants from 8 to 12 months of age. In two experiments, in which we varied the complexity of the stimuli, we first habituated infants to several scenes where the location of a target (a cartoon character) was consistently associated with a context, namely a specific configuration of geometrical shapes. Second, we examined whether infants learned the covariation between the target location and the context by measuring looking times at scenes that either respected or violated the association. In both experiments, results showed that infants learned the target-context associations, as they looked longer at the familiar scenes than at the novel ones. In particular, infants selected clusters of co-occurring contextual shapes and learned the covariation between the target location and this subset. These results support the existence of a powerful and versatile statistical learning mechanism that may influence the orientation of infants' visual attention toward areas of interest in their environment during early developmental stages. A video abstract of this article can be viewed at: https://www.youtube.com/watch?v=9Hm1unyLBn0. © 2016 John Wiley & Sons Ltd.

  16. Fuzzy OLAP association rules mining-based modular reinforcement learning approach for multiagent systems.

    Science.gov (United States)

    Kaya, Mehmet; Alhajj, Reda

    2005-04-01

    Multiagent systems and data mining have recently attracted considerable attention in the field of computing. Reinforcement learning is the most commonly used learning process for multiagent systems. However, it still has some drawbacks, including modeling other learning agents present in the domain as part of the state of the environment, and some states are experienced much less than others, or some state-action pairs are never visited during the learning phase. Further, before completing the learning process, an agent cannot exhibit a certain behavior in some states that may be experienced sufficiently. In this study, we propose a novel multiagent learning approach to handle these problems. Our approach is based on utilizing the mining process for modular cooperative learning systems. It incorporates fuzziness and online analytical processing (OLAP) based mining to effectively process the information reported by agents. First, we describe a fuzzy data cube OLAP architecture which facilitates effective storage and processing of the state information reported by agents. This way, the action of the other agent, not even in the visual environment. of the agent under consideration, can simply be predicted by extracting online association rules, a well-known data mining technique, from the constructed data cube. Second, we present a new action selection model, which is also based on association rules mining. Finally, we generalize not sufficiently experienced states, by mining multilevel association rules from the proposed fuzzy data cube. Experimental results obtained on two different versions of a well-known pursuit domain show the robustness and effectiveness of the proposed fuzzy OLAP mining based modular learning approach. Finally, we tested the scalability of the approach presented in this paper and compared it with our previous work on modular-fuzzy Q-learning and ordinary Q-learning.

  17. Failing to learn from negative prediction errors: Obesity is associated with alterations in a fundamental neural learning mechanism.

    Science.gov (United States)

    Mathar, David; Neumann, Jane; Villringer, Arno; Horstmann, Annette

    2017-10-01

    Prediction errors (PEs) encode the difference between expected and actual action outcomes in the brain via dopaminergic modulation. Integration of these learning signals ensures efficient behavioral adaptation. Obesity has recently been linked to altered dopaminergic fronto-striatal circuits, thus implying impairments in cognitive domains that rely on its integrity. 28 obese and 30 lean human participants performed an implicit stimulus-response learning paradigm inside an fMRI scanner. Computational modeling and psycho-physiological interaction (PPI) analysis was utilized for assessing PE-related learning and associated functional connectivity. We show that human obesity is associated with insufficient incorporation of negative PEs into behavioral adaptation even in a non-food context, suggesting differences in a fundamental neural learning mechanism. Obese subjects were less efficient in using negative PEs to improve implicit learning performance, despite proper coding of PEs in striatum. We further observed lower functional coupling between ventral striatum and supplementary motor area in obese subjects subsequent to negative PEs. Importantly, strength of functional coupling predicted task performance and negative PE utilization. These findings show that obesity is linked to insufficient behavioral adaptation specifically in response to negative PEs, and to associated alterations in function and connectivity within the fronto-striatal system. Recognition of neural differences as a central characteristic of obesity hopefully paves the way to rethink established intervention strategies: Differential behavioral sensitivity to negative and positive PEs should be considered when designing intervention programs. Measures relying on penalization of unwanted behavior may prove less effective in obese subjects than alternative approaches. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Strategies to associate memories by unsupervised learning in neural networks

    Science.gov (United States)

    Agnes, E. J.; Mizusaki, B. E. P.; Erichsen, R., Jr.; Brunnet, L. G.

    2013-01-01

    In this work we study the effects of three different strategies to associate memories in a neural network composed by both excitatory and inhibitory spiking neurons, which are randomly connected through recurrent excitatory and inhibitory synapses. The system is intended to store a number of memories, associated to spatial external inputs. The strategies consist in the presentation of the input patterns through trials in: i) ordered sequence; ii) random sequence; iii) clustered sequences. In addition, an order parameter indicating the correlation between the trials' activities is introduced to compute associative memory capacities and the quality of memory retrieval.

  19. Associative learning phenomena in the snail (Helix aspersa): conditioned inhibition.

    Science.gov (United States)

    Acebes, Félix; Solar, Patricia; Moris, Joaquín; Loy, Ignacio

    2012-03-01

    Two experiments using garden snails (Helix aspersa) showed conditioned inhibition using both retardation and summation tests. Conditioned inhibition is a procedure by which a stimulus becomes a predictor of the absence of a relevant event--the unconditioned stimulus (US). Typically, conditioned inhibition consists of pairings between an initially neutral conditioned stimulus, CS(2), and an effective excitatory conditioned stimulus, CS(1), in the absence of the US. Retardation and summation tests are required in order to confirm that CS(2) has acquired inhibitory properties. Conditioned inhibition has previously been found in invertebrates; however, these demonstrations did not use the retardation and summation tests required for an unambiguous demonstration of inhibition, allowing for alternative explanations. The implications of our results for the fields of comparative cognition and invertebrate physiological models of learning are discussed.

  20. Is problem-based learning associated with students’ motivation? A quantitative and qualitative study

    NARCIS (Netherlands)

    M. Wijnen (Marit); S.M.M. Loyens (Sofie); L. Wijnia (Lisette); G. Smeets (Guus); M.J. Kroeze (Maarten); H.T. van der Molen (Henk)

    2017-01-01

    textabstractIn this study, a mixed-method design was employed to investigate the association between a student-centred, problem-based learning (PBL) method and law students’ motivation. Self-determination theory (SDT) states that autonomous motivation, which is associated with higher academic

  1. The Acquisition of Simple Associations as Observed in Color-Word Contingency Learning

    Science.gov (United States)

    Lin, Olivia Y.-H.; MacLeod, Colin M.

    2018-01-01

    Three experiments investigated the learning of simple associations in a color-word contingency task. Participants responded manually to the print colors of 3 words, with each word associated strongly to 1 of the 3 colors and weakly to the other 2 colors. Despite the words being irrelevant, response times to high-contingency stimuli and to…

  2. Learning Curve Characteristics for Caesarean Section Among Associate Clinicians : A Prospective Study from Sierra Leone

    NARCIS (Netherlands)

    Waalewijn, B.P.; van Duinen, A.; Koroma, A. P.; Rijken, M. J.; Elhassein, M.; Bolkan, H. A.

    2017-01-01

    Background: In response to the high maternal mortality ratio, Sierra Leone has adopted an associate clinician postgraduate surgical task-sharing training programme. Little is known about learning curve characteristics for caesarean sections among associate clinicians. The aim of this study is to

  3. Efficient learning of microbial genotype-phenotype association rules.

    Science.gov (United States)

    MacDonald, Norman J; Beiko, Robert G

    2010-08-01

    Finding biologically causative genotype-phenotype associations from whole-genome data is difficult due to the large gene feature space to mine, the potential for interactions among genes and phylogenetic correlations between genomes. Associations within phylogenetically distinct organisms with unusual molecular mechanisms underlying their phenotype may be particularly difficult to assess. We have developed a new genotype-phenotype association approach that uses Classification based on Predictive Association Rules (CPAR), and compare it with NETCAR, a recently published association algorithm. Our implementation of CPAR gave on average slightly higher classification accuracy, with approximately 100 time faster running times. Given the influence of phylogenetic correlations in the extraction of genotype-phenotype association rules, we furthermore propose a novel measure for downweighting the dependence among samples by modeling shared ancestry using conditional mutual information, and demonstrate its complementary nature to traditional mining approaches. Software implemented for this study is available under the Creative Commons Attribution 3.0 license from the author at http://kiwi.cs.dal.ca/Software/PICA

  4. The "proactive" model of learning: Integrative framework for model-free and model-based reinforcement learning utilizing the associative learning-based proactive brain concept.

    Science.gov (United States)

    Zsuga, Judit; Biro, Klara; Papp, Csaba; Tajti, Gabor; Gesztelyi, Rudolf

    2016-02-01

    Reinforcement learning (RL) is a powerful concept underlying forms of associative learning governed by the use of a scalar reward signal, with learning taking place if expectations are violated. RL may be assessed using model-based and model-free approaches. Model-based reinforcement learning involves the amygdala, the hippocampus, and the orbitofrontal cortex (OFC). The model-free system involves the pedunculopontine-tegmental nucleus (PPTgN), the ventral tegmental area (VTA) and the ventral striatum (VS). Based on the functional connectivity of VS, model-free and model based RL systems center on the VS that by integrating model-free signals (received as reward prediction error) and model-based reward related input computes value. Using the concept of reinforcement learning agent we propose that the VS serves as the value function component of the RL agent. Regarding the model utilized for model-based computations we turned to the proactive brain concept, which offers an ubiquitous function for the default network based on its great functional overlap with contextual associative areas. Hence, by means of the default network the brain continuously organizes its environment into context frames enabling the formulation of analogy-based association that are turned into predictions of what to expect. The OFC integrates reward-related information into context frames upon computing reward expectation by compiling stimulus-reward and context-reward information offered by the amygdala and hippocampus, respectively. Furthermore we suggest that the integration of model-based expectations regarding reward into the value signal is further supported by the efferent of the OFC that reach structures canonical for model-free learning (e.g., the PPTgN, VTA, and VS). (c) 2016 APA, all rights reserved).

  5. Observational Word Learning: Beyond Propose-But-Verify and Associative Bean Counting.

    Science.gov (United States)

    Roembke, Tanja; McMurray, Bob

    2016-04-01

    Learning new words is difficult. In any naming situation, there are multiple possible interpretations of a novel word. Recent approaches suggest that learners may solve this problem by tracking co-occurrence statistics between words and referents across multiple naming situations (e.g. Yu & Smith, 2007), overcoming the ambiguity in any one situation. Yet, there remains debate around the underlying mechanisms. We conducted two experiments in which learners acquired eight word-object mappings using cross-situational statistics while eye-movements were tracked. These addressed four unresolved questions regarding the learning mechanism. First, eye-movements during learning showed evidence that listeners maintain multiple hypotheses for a given word and bring them all to bear in the moment of naming. Second, trial-by-trial analyses of accuracy suggested that listeners accumulate continuous statistics about word/object mappings, over and above prior hypotheses they have about a word. Third, consistent, probabilistic context can impede learning, as false associations between words and highly co-occurring referents are formed. Finally, a number of factors not previously considered in prior analysis impact observational word learning: knowledge of the foils, spatial consistency of the target object, and the number of trials between presentations of the same word. This evidence suggests that observational word learning may derive from a combination of gradual statistical or associative learning mechanisms and more rapid real-time processes such as competition, mutual exclusivity and even inference or hypothesis testing.

  6. Reorganization and plastic changes of the human brain associated with skill learning and expertise

    Directory of Open Access Journals (Sweden)

    Yongmin eChang

    2014-02-01

    Full Text Available Novel experience and learning new skills are known as modulators of brain function. Advances in non-invasive brain imaging have provided new insight into structural and functional reorganization associated with skill learning and expertise. Especially, significant imaging evidences come from the domains of sports and music. Data from in vivo imaging studies in sports and music have provided vital information on plausible neural substrates contributing to brain reorganization underlying skill acquisition in humans. This mini review will attempt to take a narrow snapshot of imaging findings demonstrating functional and structural plasticity that mediate skill learning and expertise while identifying converging areas of interest and possible avenues for future research.

  7. SPAN: spike pattern association neuron for learning spatio-temporal sequences

    OpenAIRE

    Mohemmed, A; Schliebs, S; Matsuda, S; Kasabov, N

    2012-01-01

    Spiking Neural Networks (SNN) were shown to be suitable tools for the processing of spatio-temporal information. However, due to their inherent complexity, the formulation of efficient supervised learning algorithms for SNN is difficult and remains an important problem in the research area. This article presents SPAN — a spiking neuron that is able to learn associations of arbitrary spike trains in a supervised fashion allowing the processing of spatio-temporal information encoded in the prec...

  8. Nicotine disrupts safety learning by enhancing fear associated with a safety cue via the dorsal hippocampus.

    Science.gov (United States)

    Connor, David A; Kutlu, Munir G; Gould, Thomas J

    2017-07-01

    Learned safety, a learning process in which a cue becomes associated with the absence of threat, is disrupted in individuals with post-traumatic stress disorder (PTSD). A bi-directional relationship exists between smoking and PTSD and one potential explanation is that nicotine-associated changes in cognition facilitate PTSD emotional dysregulation by disrupting safety associations. Therefore, we investigated whether nicotine would disrupt learned safety by enhancing fear associated with a safety cue. In the present study, C57BL/6 mice were administered acute or chronic nicotine and trained over three days in a differential backward trace conditioning paradigm consisting of five trials of a forward conditioned stimulus (CS)+ (Light) co-terminating with a footshock unconditioned stimulus followed by a backward CS- (Tone) presented 20 s after cessation of the unconditioned stimulus. Summation testing found that acute nicotine disrupted learned safety, but chronic nicotine had no effect. Another group of animals administered acute nicotine showed fear when presented with the backward CS (Light) alone, indicating the formation of a maladaptive fear association with the backward CS. Finally, we investigated the brain regions involved by administering nicotine directly into the dorsal hippocampus, ventral hippocampus, and prelimbic cortex. Infusion of nicotine into the dorsal hippocampus disrupted safety learning.

  9. Associative learning, acquired equivalence, and flexible generalization of knowledge in mild Alzheimer disease.

    Science.gov (United States)

    Bódi, Nikoletta; Csibri, Eva; Myers, Catherine E; Gluck, Mark A; Kéri, Szabolcs

    2009-06-01

    Acquired equivalence is a phenomenon in which prior training to treat 2 stimuli as equivalent increases generalization between them. Previous studies demonstrated that the hippocampal complex might play an important role in acquired equivalence associative learning. In this study, we tested the possibility that acquired equivalence learning is a sensitive marker of mild Alzheimer disease (AD). In the associative learning test, antecedent stimuli were cartoon faces and consequent stimuli were different colored cartoon fishes. Each cartoon character had some pet fish and the task was to learn these face-fish associations using feedback provided after each decision. In the transfer phase, knowledge about face-fish pairs had to be generalized to new associations. AD patients exhibited mild impairments in the training phase, whereas they were profoundly impaired on the acquired equivalence test. Associative knowledge could not be transferred to a more flexible retrieval condition. These results suggest that acquired equivalence learning is specifically impaired in early AD, which may indicate the pathology of the hippocampal complex.

  10. Stable Isotope Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Tissue samples (skin, bone, blood, muscle) are analyzed for stable carbon, stable nitrogen, and stable sulfur analysis. Many samples are used in their entirety for...

  11. Fast but fleeting: adaptive motor learning processes associated with aging and cognitive decline.

    Science.gov (United States)

    Trewartha, Kevin M; Garcia, Angeles; Wolpert, Daniel M; Flanagan, J Randall

    2014-10-01

    Motor learning has been shown to depend on multiple interacting learning processes. For example, learning to adapt when moving grasped objects with novel dynamics involves a fast process that adapts and decays quickly-and that has been linked to explicit memory-and a slower process that adapts and decays more gradually. Each process is characterized by a learning rate that controls how strongly motor memory is updated based on experienced errors and a retention factor determining the movement-to-movement decay in motor memory. Here we examined whether fast and slow motor learning processes involved in learning novel dynamics differ between younger and older adults. In addition, we investigated how age-related decline in explicit memory performance influences learning and retention parameters. Although the groups adapted equally well, they did so with markedly different underlying processes. Whereas the groups had similar fast processes, they had different slow processes. Specifically, the older adults exhibited decreased retention in their slow process compared with younger adults. Within the older group, who exhibited considerable variation in explicit memory performance, we found that poor explicit memory was associated with reduced retention in the fast process, as well as the slow process. These findings suggest that explicit memory resources are a determining factor in impairments in the both the fast and slow processes for motor learning but that aging effects on the slow process are independent of explicit memory declines. Copyright © 2014 the authors 0270-6474/14/3413411-11$15.00/0.

  12. Does academic performance or personal growth share a stronger association with learning environment perception?

    Science.gov (United States)

    Colbert-Getz, Jorie M; Tackett, Sean; Wright, Scott M; Shochet, Robert S

    2016-08-28

    This study was conducted to characterize the relative strength of associations of learning environment perception with academic performance and with personal growth. In 2012-2014 second and third year students at Johns Hopkins University School of Medicine completed a learning environment survey and personal growth scale. Hierarchical linear regression analysis was employed to determine if the proportion of variance in learning environment scores accounted for by personal growth was significantly larger than the proportion accounted for by academic performance (course/clerkship grades). The proportion of variance in learning environment scores accounted for by personal growth was larger than the proportion accounted for by academic performance in year 2 [R(2)Δ of 0.09, F(1,175) = 14.99,  p Learning environment scores shared a small amount of variance with academic performance in years 2 and 3.  The amount of variance between learning environment scores and personal growth was small in year 2 and large in year 3. Since supportive learning environments are essential for medical education, future work must determine if enhancing personal growth prior to and during the clerkship year will increase learning environment perception.

  13. Good night, sleep tight: The effects of sleep deprivation on spatial associative learning in zebrafish.

    Science.gov (United States)

    Pinheiro-da-Silva, Jaquelinne; Tran, Steven; Silva, Priscila Fernandes; Luchiari, Ana Carolina

    2017-08-01

    Learning and memory are vital to an animal's survival, and numerous factors can disrupt cognitive performance. Sleep is an evolutionarily conserved physiological process known to be important for the consolidation of learning and memory. The zebrafish has emerged as a powerful model organism sharing organizational and functional characteristics with other vertebrates, providing great translational relevance. In our study, we used a simple spatial associative learning task to quantify the effects of sleep deprivation (partial vs. total) on learning performance in zebrafish, using an animated conspecific shoal image as a reward. Control animals maintained on a regular light:dark cycle were able to acquire the association between the unconditioned and conditioned stimulus, reinforcing zebrafish as a valid and reliable model for appetitive conditioning tasks. Notably, sleep deprivation did not alter the perception of and response to the conspecific image. In contrast, although partial sleep deprivation did not impair cognitive performance, total sleep deprivation significantly impaired performance on the associative learning task. Our results suggest that sleep is important for learning and memory, and that the effects of sleep deprivation on these processes can be investigated in zebrafish. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Addressing the Learning Outcomes and Assessment Methods Associated with Participation in Student Government Associations: A Qualitative Study of California Community Colleges

    Science.gov (United States)

    Nevin, Miles J.

    2017-01-01

    This document analysis synthesized student learning outcomes (SLOs) and assessment methods from a sample of 36 student government associations in the California Community College system. Student learning outcomes were grouped according to "governance, ethical and civic behavior", and "experiential learning functions." Using…

  15. Adiponectin is associated with increased mortality and heart failure in patients with stable ischemic heart disease: data from the Heart and Soul Study.

    Science.gov (United States)

    Beatty, Alexis L; Zhang, Mary H; Ku, Ivy A; Na, Beeya; Schiller, Nelson B; Whooley, Mary A

    2012-02-01

    Serum adiponectin protects against incident ischemic heart disease (IHD). However, in patients with existing IHD, higher adiponectin levels are paradoxically associated with worse outcomes. We investigated this paradox by evaluating the relationship between adiponectin and cardiovascular events in patients with existing IHD. We measured total serum adiponectin and cardiac disease severity by stress echocardiography in 981 outpatients with stable IHD who were recruited for the Heart and Soul Study between September 2000 and December 2002. Subsequent heart failure hospitalizations, myocardial infarction, and death were recorded. During an average of 7.1 years of follow-up, patients with adiponectin levels in the highest quartile were more likely than those in the lowest quartile to be hospitalized for heart failure (23% vs. 13%; demographics-adjusted hazard ratio (HR) 1.63, 95% confidence interval (CI) 1.04-2.56, p=0.03) or die (49% vs. 31%; HR 1.67, 95% CI 1.24-2.26, pheart failure, or death occurred in 56% (136/245) of participants in the highest quartile of adiponectin vs. 38% (94/246) of participants in the lowest quartile (HR 1.54, 95% CI 1.31-2.21, pheart failure and mortality among patients with existing IHD. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  16. Sleep directly following learning benefits consolidation of spatial associative memory

    NARCIS (Netherlands)

    Talamini, L.M.; Nieuwenhuis, I.L.C.; Takashima, A.

    2008-01-01

    The last decade has brought forth convincing evidence for a role of sleep in non-declarative memory. A similar function of sleep in episodic memory is supported by various correlational studies, but direct evidence is limited. Here we show that cued recall of face–location associations is

  17. Sleep directly following learning benefits consolidation of spatial associative memory

    NARCIS (Netherlands)

    Talamini, L.M.; Nieuwenhuis, I.L.C.; Takashima, A.; Jensen, O.

    2008-01-01

    The last decade has brought forth convincing evidence for a role of sleep in non-declarative memory. A similar function of sleep in episodic memory is supported by various correlational studies, but direct evidence is limited. Here we show that cued recall of face-location associations is

  18. Low paraoxonase 1 arylesterase activity and high von Willebrand factor levels are associated with severe coronary atherosclerosis in patients with non-diabetic stable coronary artery disease.

    Science.gov (United States)

    Ding, Jieying; Chen, Qizhi; Zhuang, Xing; Feng, Zhilei; Xu, Lili; Chen, Fuxiang

    2014-11-25

    Paraoxonase 1 (PON1) activity and von Willebrand factor (VWF) release are associated with lesion initiation in atherosclerosis. Diabetes can complicate coronary artery disease (CAD) due to the production of advanced glycation end products. This study evaluated PON1 activity and VWF levels in non-post-acute coronary syndrome, stable CAD (SCAD) patients without diabetes. Non-diabetic SCAD patients and patients experiencing acute stress periods were selected (n=130). Forty-seven cases with normal coronary angiography and 50 healthy individuals served as controls. The non-diabetic SCAD group was then stratified into single-vessel lesions, multiple-vessel lesions, and mild or severe luminal stenosis according to the number and the degree of luminal stenoses. Serum PON1 paraoxonase and arylesterase activities, and plasma VWF levels were measured, as well as serum total cholesterol, total triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and apolipoprotein A1. PON1 arylesterase activity was detected with an ordinary chemistry system using a novel phenylacetate derivative. Both PON1 paraoxonase and arylesterase were lower in the non-diabetic SCAD group, but VWF levels were higher (versus controls, all Pparaoxonase activity (OR=0.991), PON1 arylesterase activity (OR=0.981), and VWF (OR 2.854) influenced SCAD in multiple logistic regression. Decreased PON1 arylesterase activity and increased VWF levels were associated with severe atherosclerosis in non-diabetic SCAD patients. We also observed a slight negative correlation between VWF and PON1 paraoxonase/arylesterase. PON1 and VWF are detectable markers that may predict the severity of stenoses, ideally facilitating a non-diabetic SCAD diagnosis before the sudden onset of life-threatening symptoms.

  19. Elemental representation and configural mappings: combining elemental and configural theories of associative learning.

    Science.gov (United States)

    McLaren, I P L; Forrest, C L; McLaren, R P

    2012-09-01

    In this article, we present our first attempt at combining an elemental theory designed to model representation development in an associative system (based on McLaren, Kaye, & Mackintosh, 1989) with a configural theory that models associative learning and memory (McLaren, 1993). After considering the possible advantages of such a combination (and some possible pitfalls), we offer a hybrid model that allows both components to produce the phenomena that they are capable of without introducing unwanted interactions. We then successfully apply the model to a range of phenomena, including latent inhibition, perceptual learning, the Espinet effect, and first- and second-order retrospective revaluation. In some cases, we present new data for comparison with our model's predictions. In all cases, the model replicates the pattern observed in our experimental results. We conclude that this line of development is a promising one for arriving at general theories of associative learning and memory.

  20. Storage and recall capabilities of fuzzy morphological associative memories with adjunction-based learning.

    Science.gov (United States)

    Valle, Marcos Eduardo; Sussner, Peter

    2011-01-01

    We recently employed concepts of mathematical morphology to introduce fuzzy morphological associative memories (FMAMs), a broad class of fuzzy associative memories (FAMs). We observed that many well-known FAM models can be classified as belonging to the class of FMAMs. Moreover, we developed a general learning strategy for FMAMs using the concept of adjunction of mathematical morphology. In this paper, we describe the properties of FMAMs with adjunction-based learning. In particular, we characterize the recall phase of these models. Furthermore, we prove several theorems concerning the storage capacity, noise tolerance, fixed points, and convergence of auto-associative FMAMs. These theorems are corroborated by experimental results concerning the reconstruction of noisy images. Finally, we successfully employ FMAMs with adjunction-based learning in order to implement fuzzy rule-based systems in an application to a time-series prediction problem in industry. Copyright © 2010 Elsevier Ltd. All rights reserved.

  1. Chronological age and its impact on associative learning proficiency and brain structure in middle adulthood.

    Science.gov (United States)

    Diwadkar, Vaibhav A; Bellani, Marcella; Ahmed, Rizwan; Dusi, Nicola; Rambaldelli, Gianluca; Perlini, Cinzia; Marinelli, Veronica; Ramaseshan, Karthik; Ruggeri, Mirella; Bambilla, Paolo

    2016-01-15

    The rate of biological change in middle-adulthood is relatively under-studied. Here, we used behavioral testing in conjunction with structural magnetic resonance imaging to examine the effects of chronological age on associative learning proficiency and on brain regions that previous functional MRI studies have closely related to the domain of associative learning. Participants (n=66) completed a previously established associative learning paradigm, and consented to be scanned using structural magnetic resonance imaging. Age-related effects were investigated both across sub-groups in the sample (younger vs. older) and across the entire sample (using regression approaches). Chronological age had substantial effects on learning proficiency (independent of IQ and Education Level), with older adults showing a decrement compared to younger adults. In addition, decreases in estimated gray matter volume were observed in multiple brain regions including the hippocampus and the dorsal prefrontal cortex, both of which are strongly implicated in associative learning. The results suggest that middle adulthood may be a more dynamic period of life-span change than previously believed. The conjunctive application of narrowly focused tasks, with conjointly acquired structural MRI data may allow us to enrich the search for, and the interpretation of, age-related changes in cross-sectional samples. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. BDNF Val66Met Polymorphism Influences Visuomotor Associative Learning and the Sensitivity to Action Observation

    Science.gov (United States)

    Taschereau-Dumouchel, Vincent; Hétu, Sébastien; Michon, Pierre-Emmanuel; Vachon-Presseau, Etienne; Massicotte, Elsa; De Beaumont, Louis; Fecteau, Shirley; Poirier, Judes; Mercier, Catherine; Chagnon, Yvon C.; Jackson, Philip L.

    2016-01-01

    Motor representations in the human mirror neuron system are tuned to respond to specific observed actions. This ability is widely believed to be influenced by genetic factors, but no study has reported a genetic variant affecting this system so far. One possibility is that genetic variants might interact with visuomotor associative learning to configure the system to respond to novel observed actions. In this perspective, we conducted a candidate gene study on the Brain-derived neurotrophic factor (BDNF) Val66Met polymorphism, a genetic variant linked to motor learning in regions of the mirror neuron system, and tested the effect of this polymorphism on motor facilitation and visuomotor associative learning. In a single-pulse TMS study carried on 16 Met (Val/Met and Met/Met) and 16 Val/Val participants selected from a large pool of healthy volunteers, Met participants showed significantly less muscle-specific corticospinal sensitivity during action observation, as well as reduced visuomotor associative learning, compared to Val homozygotes. These results are the first evidence of a genetic variant tuning sensitivity to action observation and bring to light the importance of considering the intricate relation between genetics and associative learning in order to further understand the origin and function of the human mirror neuron system. PMID:27703276

  3. Associative learning changes cross-modal representations in the gustatory cortex.

    Science.gov (United States)

    Vincis, Roberto; Fontanini, Alfredo

    2016-08-30

    A growing body of literature has demonstrated that primary sensory cortices are not exclusively unimodal, but can respond to stimuli of different sensory modalities. However, several questions concerning the neural representation of cross-modal stimuli remain open. Indeed, it is poorly understood if cross-modal stimuli evoke unique or overlapping representations in a primary sensory cortex and whether learning can modulate these representations. Here we recorded single unit responses to auditory, visual, somatosensory, and olfactory stimuli in the gustatory cortex (GC) of alert rats before and after associative learning. We found that, in untrained rats, the majority of GC neurons were modulated by a single modality. Upon learning, both prevalence of cross-modal responsive neurons and their breadth of tuning increased, leading to a greater overlap of representations. Altogether, our results show that the gustatory cortex represents cross-modal stimuli according to their sensory identity, and that learning changes the overlap of cross-modal representations.

  4. Powerful Tests for Multi-Marker Association Analysis Using Ensemble Learning.

    Directory of Open Access Journals (Sweden)

    Badri Padhukasahasram

    Full Text Available Multi-marker approaches have received a lot of attention recently in genome wide association studies and can enhance power to detect new associations under certain conditions. Gene-, gene-set- and pathway-based association tests are increasingly being viewed as useful supplements to the more widely used single marker association analysis which have successfully uncovered numerous disease variants. A major drawback of single-marker based methods is that they do not look at the joint effects of multiple genetic variants which individually may have weak or moderate signals. Here, we describe novel tests for multi-marker association analyses that are based on phenotype predictions obtained from machine learning algorithms. Instead of assuming a linear or logistic regression model, we propose the use of ensembles of diverse machine learning algorithms for prediction. We show that phenotype predictions obtained from ensemble learning algorithms provide a new framework for multi-marker association analysis. They can be used for constructing tests for the joint association of multiple variants, adjusting for covariates and testing for the presence of interactions. To demonstrate the power and utility of this new approach, we first apply our method to simulated SNP datasets. We show that the proposed method has the correct Type-1 error rates and can be considerably more powerful than alternative approaches in some situations. Then, we apply our method to previously studied asthma-related genes in 2 independent asthma cohorts to conduct association tests.

  5. Multi-label Learning for Detection of CME-Associated Phenomena

    Science.gov (United States)

    Yang, Y. H.; Tian, H. M.; Peng, B.; Li, T. R.; Xie, Z. X.

    2017-09-01

    Coronal mass ejections (CMEs) are considered as one of the driving sources of space weather. They are usually associated with many physical phenomena, e.g. flares, coronal dimmings, and sigmoids. To detect these phenomena, traditional supervised-learning methods assumed that at most one event occurred in a CME; therefore each CME instance is associated with a single label and the phenomenon is processed in isolation. This simplifying assumption does not fit well, as CMEs might have multiple events simultaneously. We propose to detect multiple CME-associated events by multi-label learning methods. With the data available from the Atmospheric Imaging Assembly (AIA) and the Large Angle and Spectrometric Coronagraph (LASCO), texture features representing the events are extracted from all of the associated and not-associated CMEs and converted into feature vectors for multi-label learning use. Then a function is learned to predict the proper label sets for CMEs, such that eight events, i.e. coronal dimming, coronal hole, coronal jet, coronal wave, filament, filament eruption, flare, and sigmoid, are detected explicitly. To test the proposed detection algorithm, we adopt the four-fold cross-validation strategy on a set of 551 labeled CMEs from AIA. Experimental results demonstrate the good performance of the multi-label classification methods in terms of test error.

  6. Bayesian methods for addressing long-standing problems in associative learning: The case of PREE.

    Science.gov (United States)

    Blanco, Fernando; Moris, Joaquín

    2017-07-20

    Most associative models typically assume that learning can be understood as a gradual change in associative strength that captures the situation into one single parameter, or representational state. We will call this view single-state learning. However, there is ample evidence showing that under many circumstances different relationships that share features can be learned independently, and animals can quickly switch between expressing one or another. We will call this multiple-state learning. Theoretically, it is understudied because it needs a different data analysis approach from those usually employed. In this paper, we present a Bayesian model of the Partial Reinforcement Extinction Effect (PREE) that can test the predictions of the multiple-state view. This implies estimating the moment of change in the responses (from the acquisition to the extinction performance), both at the individual and at the group levels. We used this model to analyze data from a PREE experiment with three levels of reinforcement during acquisition (100%, 75% and 50%). We found differences in the estimated moment of switch between states during extinction, so that it was delayed after leaner partial reinforcement schedules. The finding is compatible with the multiple-state view. It is the first time, to our knowledge, that the predictions from the multiple-state view are tested directly. The paper also aims to show the benefits that Bayesian methods can bring to the associative learning field.

  7. Distinct roles of the RasGAP family proteins in C. elegans associative learning and memory.

    Science.gov (United States)

    Gyurkó, M Dávid; Csermely, Péter; Sőti, Csaba; Steták, Attila

    2015-10-15

    The Ras GTPase activating proteins (RasGAPs) are regulators of the conserved Ras/MAPK pathway. Various roles of some of the RasGAPs in learning and memory have been reported in different model systems, yet, there is no comprehensive study to characterize all gap genes in any organism. Here, using reverse genetics and neurobehavioural tests, we studied the role of all known genes of the rasgap family in C. elegans in associative learning and memory. We demonstrated that their proteins are implicated in different parts of the learning and memory processes. We show that gap-1 contribute redundantly with gap-3 to the chemosensation of volatile compounds, gap-1 plays a major role in associative learning, while gap-2 and gap-3 are predominantly required for short- and long-term associative memory. Our results also suggest that the C. elegans Ras orthologue let-60 is involved in multiple processes during learning and memory. Thus, we show that the different classes of RasGAP proteins are all involved in cognitive function and their complex interplay ensures the proper formation and storage of novel information in C. elegans.

  8. Differential contribution of hippocampal subfields to components of associative taste learning.

    Science.gov (United States)

    Chinnakkaruppan, Adaikkan; Wintzer, Marie E; McHugh, Thomas J; Rosenblum, Kobi

    2014-08-13

    The ability to associate the consumption of a taste with its positive or negative consequences is fundamental to survival and influences the behavior of species ranging from invertebrate to human. As a result, for both research and clinical reasons, there has been a great effort to understand the neuronal circuits, as well as the cellular and molecular mechanisms, underlying taste learning. From a neuroanatomical perspective, the contributions of the cortex and amygdala are well documented; however, the literature is riddled with conflicting results regarding the role of the hippocampus in different facets of taste learning. Here, we use conditional genetics in mice to block NMDA receptor-dependent plasticity individually in each of the three major hippocampal subfields, CA1, CA3, and the dentate gyrus, via deletion of the NR1 subunit. Across the CA1, CA3, and dentate gyrus NR1 knock-out lines, we uncover a pattern of differential deficits that establish the dispensability of hippocampal plasticity in incidental taste learning, the requirement of CA1 plasticity for associative taste learning, and a specific requirement for plasticity in the dentate gyrus when there is a long temporal gap between the taste and its outcome. Together, these data establish that the hippocampus is involved in associative taste learning and suggest an episodic component to this type of memory. Copyright © 2014 the authors 0270-6474/14/3411007-09$15.00/0.

  9. Adult Hippocampal Neurogenesis Modulates Fear Learning through Associative and Nonassociative Mechanisms

    Science.gov (United States)

    Seo, Dong-oh; Carillo, Mary Ann; Chih-Hsiung Lim, Sean; Tanaka, Kenji F.

    2015-01-01

    Adult hippocampal neurogenesis is believed to support hippocampus-dependent learning and emotional regulation. These putative functions of adult neurogenesis have typically been studied in isolation, and little is known about how they interact to produce adaptive behavior. We used trace fear conditioning as a model system to elucidate mechanisms through which adult hippocampal neurogenesis modulates processing of aversive experience. To achieve a specific ablation of neurogenesis, we generated transgenic mice that express herpes simplex virus thymidine kinase specifically in neural progenitors and immature neurons. Intracerebroventricular injection of the prodrug ganciclovir caused a robust suppression of neurogenesis without suppressing gliogenesis. Neurogenesis ablation via this method or targeted x-irradiation caused an increase in context conditioning in trace but not delay fear conditioning. Data suggest that this phenotype represents opposing effects of neurogenesis ablation on associative and nonassociative components of fear learning. Arrest of neurogenesis sensitizes mice to nonassociative effects of fear conditioning, as evidenced by increased anxiety-like behavior in the open field after (but not in the absence of) fear conditioning. In addition, arrest of neurogenesis impairs associative trace conditioning, but this impairment can be masked by nonassociative fear. The results suggest that adult neurogenesis modulates emotional learning via two distinct but opposing mechanisms: it supports associative trace conditioning while also buffering against the generalized fear and anxiety caused by fear conditioning. SIGNIFICANCE STATEMENT The role of adult hippocampal neurogenesis in fear learning is controversial, with some studies suggesting neurogenesis is needed for aspects of fear learning and others suggesting it is dispensable. We generated transgenic mice in which neural progenitors can be selectively and inducibly ablated. Our data suggest that adult

  10. Tuna and dolphin associations in the North-east Atlantic: Evidence of different ecological niches from stable isotope and heavy metal measurements

    Energy Technology Data Exchange (ETDEWEB)

    Das, K.; Lepoint, G.; Loizeau, V.; Debacker, V.; Dauby, P.; Bouquegneau, J.M

    2000-02-01

    Associations of tunas and dolphins in the wild are quite frequent events and the question arises how predators requiring similar diet in the same habitat share their environmental resources. As isotopic composition of an animal is related to that of its preys, stable isotope ({sup 13}C/{sup 12}C and {sup 15}N/{sup 14}N) analyses were performed in three predator species from the North-east Atlantic: the striped dolphin, Stenella coeruleoalba, the common dolphin Delphinus delphis and the albacore tuna, Thunnus alalunga, and compared to their previously described stomach content. Heavy metals (Cd, Zn, Cu and Fe) are mainly transferred through the diet and so, have been determined in the tissues of the animals. Tuna muscles display higher {delta}{sup 15}N than in common and striped dolphins (mean: 11.4 vs. 10.3%o and 10.4%o, respectively) which reflects their higher trophic level nutrition. Higher {delta}{sup 13}C are found in common (-18.4%o) and striped dolphin (-18.1%o) muscles than in albacore tuna (-19.3%o) probably in relation with its migratory pattern. The most striking feature is the presence of two levels of cadmium concentrations in the livers of the tunas (32 mg kg{sup -1} dry weight (DW) vs. 5 mg kg{sup -1} DW). These two groups also differ by their iron concentrations and their {delta}{sup 15}N and {delta}{sup 13}C liver values. These results suggest that in the Biscay Bay, tunas occupy two different ecological niches probably based on different squid inputs in their diet.

  11. Tuna and dolphin associations in the North-east Atlantic: Evidence of different ecological niches from stable isotope and heavy metal measurements

    International Nuclear Information System (INIS)

    Das, K.; Lepoint, G.; Loizeau, V.; Debacker, V.; Dauby, P.; Bouquegneau, J.M.

    2000-01-01

    Associations of tunas and dolphins in the wild are quite frequent events and the question arises how predators requiring similar diet in the same habitat share their environmental resources. As isotopic composition of an animal is related to that of its preys, stable isotope ( 13 C/ 12 C and 15 N/ 14 N) analyses were performed in three predator species from the North-east Atlantic: the striped dolphin, Stenella coeruleoalba, the common dolphin Delphinus delphis and the albacore tuna, Thunnus alalunga, and compared to their previously described stomach content. Heavy metals (Cd, Zn, Cu and Fe) are mainly transferred through the diet and so, have been determined in the tissues of the animals. Tuna muscles display higher δ 15 N than in common and striped dolphins (mean: 11.4 vs. 10.3%o and 10.4%o, respectively) which reflects their higher trophic level nutrition. Higher δ 13 C are found in common (-18.4%o) and striped dolphin (-18.1%o) muscles than in albacore tuna (-19.3%o) probably in relation with its migratory pattern. The most striking feature is the presence of two levels of cadmium concentrations in the livers of the tunas (32 mg kg -1 dry weight (DW) vs. 5 mg kg -1 DW). These two groups also differ by their iron concentrations and their δ 15 N and δ 13 C liver values. These results suggest that in the Biscay Bay, tunas occupy two different ecological niches probably based on different squid inputs in their diet

  12. Dental Students' Study Habits in Flipped/Blended Classrooms and Their Association with Active Learning Practices.

    Science.gov (United States)

    Gadbury-Amyot, Cynthia C; Redford, Gloria J; Bohaty, Brenda S

    2017-12-01

    In recognition of the importance for dental education programs to take a student-centered approach in which students are encouraged to take responsibility for their learning, a pediatric dentistry course redesign aimed at promoting greater active and self-directed learning was implemented at one U.S. dental school. The aim of this study was to examine the association between the students' self-reported study habits and active learning practices necessary for meaningful learning in the flipped/blended classroom. A convenience sample of two classes of second-year dental students in spring 2014 (SP14, n=106) and spring 2015 (SP15, n=106) was invited to participate in the study. Of the SP14 students, 84 participated, for a response rate of 79%; of the SP15 students, 94 participated, for a response rate of 87%. Students' self-reported responses to questions about study strategies with the prerecorded lecture materials and assigned reading materials were examined. Non-parametric analyses resulted in a cohort effect, so data are reported by class. In the SP15 class, 72% reported watching all/more than half of the prerecorded lectures versus 62% of the SP14 class, with a majority watching more than one lecture per week. In the SP15 cohort, 68% used active learning strategies when watching the lectures versus 58.3% of the SP14 cohort. The time of day preferred by the majority of both cohorts for interacting with course materials was 7-11 pm. Both SP14 and SP15 students reported being unlikely to read assigned materials prior to coming to class. Overall, the course redesign appeared to engage students in self-directed active learning. However, the degree to which active learning practices were taking place to achieve meaningful learning was questionable given students' self-reported study strategies. More work is needed to examine strategies for promoting study practices that will lead to meaningful learning.

  13. Quantum-Inspired Multidirectional Associative Memory With a Self-Convergent Iterative Learning.

    Science.gov (United States)

    Masuyama, Naoki; Loo, Chu Kiong; Seera, Manjeevan; Kubota, Naoyuki

    2018-04-01

    Quantum-inspired computing is an emerging research area, which has significantly improved the capabilities of conventional algorithms. In general, quantum-inspired hopfield associative memory (QHAM) has demonstrated quantum information processing in neural structures. This has resulted in an exponential increase in storage capacity while explaining the extensive memory, and it has the potential to illustrate the dynamics of neurons in the human brain when viewed from quantum mechanics perspective although the application of QHAM is limited as an autoassociation. We introduce a quantum-inspired multidirectional associative memory (QMAM) with a one-shot learning model, and QMAM with a self-convergent iterative learning model (IQMAM) based on QHAM in this paper. The self-convergent iterative learning enables the network to progressively develop a resonance state, from inputs to outputs. The simulation experiments demonstrate the advantages of QMAM and IQMAM, especially the stability to recall reliability.

  14. Stable convergence and stable limit theorems

    CERN Document Server

    Häusler, Erich

    2015-01-01

    The authors present a concise but complete exposition of the mathematical theory of stable convergence and give various applications in different areas of probability theory and mathematical statistics to illustrate the usefulness of this concept. Stable convergence holds in many limit theorems of probability theory and statistics – such as the classical central limit theorem – which are usually formulated in terms of convergence in distribution. Originated by Alfred Rényi, the notion of stable convergence is stronger than the classical weak convergence of probability measures. A variety of methods is described which can be used to establish this stronger stable convergence in many limit theorems which were originally formulated only in terms of weak convergence. Naturally, these stronger limit theorems have new and stronger consequences which should not be missed by neglecting the notion of stable convergence. The presentation will be accessible to researchers and advanced students at the master's level...

  15. Electrophysiological CNS-processes related to associative learning in humans.

    Science.gov (United States)

    Christoffersen, Gert R J; Schachtman, Todd R

    2016-01-01

    The neurophysiology of human associative memory has been studied with electroencephalographic techniques since the 1930s. This research has revealed that different types of electrophysiological processes in the human brain can be modified by conditioning: sensory evoked potentials, sensory induced gamma-band activity, periods of frequency-specific waves (alpha and beta waves, the sensorimotor rhythm and the mu-rhythm) and slow cortical potentials. Conditioning of these processes has been studied in experiments that either use operant conditioning or repeated contingent pairings of conditioned and unconditioned stimuli (classical conditioning). In operant conditioning, the appearance of a specific brain process is paired with an external stimulus (neurofeedback) and the feedback enables subjects to obtain varying degrees of control of the CNS-process. Such acquired self-regulation of brain activity has found practical uses for instance in the amelioration of epileptic seizures, Autism Spectrum Disorders (ASD) and Attention Deficit Hyperactivity Disorder (ADHD). It has also provided communicative means of assistance for tetraplegic patients through the use of brain computer interfaces. Both extra and intracortically recorded signals have been coupled with contingent external feedback. It is the aim for this review to summarize essential results on all types of electromagnetic brain processes that have been modified by classical or operant conditioning. The results are organized according to type of conditioned EEG-process, type of conditioning, and sensory modalities of the conditioning stimuli. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Coordinating associative and ecological accounts of learning in the garden snail Cornu aspersum.

    Science.gov (United States)

    Loy, I; Álvarez, B; Strempler-Rubio, E C; Rodríguez, M

    2017-06-01

    Pavlovian conditioning of tentacle lowering in the snail, Cornu aspersum, as an instance of associative learning, has proven effective to show evidence of paradigmatic associative phenomena (e.g., blocking) explained by current models of conditioning. Nevertheless, the available literature questions the biological function of the conditioned response (i.e., tentacle lowering) in snails since no advantages in terms of food finding had been observed. Ecological accounts of learning claim that learning abilities contribute to the adaptation to the environmental demands, and there is experimental evidence supporting this in several species (e.g., grasshoppers, fish, or antlions). However, there is a lack of evidence in snails, which is surprising given that the conditioned response of tentacle lowering is a robust finding that fits in with several predictions of associative learning theory (e.g., blocking or conditioned inhibition). The goal of this manuscript was to test whether food detection is affected by prior experience with the food, distance, and conditioning. We found that prior experience with a food source is necessary for snails to locate the same food item; that the optimal distance to test for food detection is between 5 and 7cm and that snails seem to use different food searching strategies after conditioning depending on the stimuli that are present. The data provided constitute a small contribution to the vindication of a greater coordination between the fruitful research tool provided by the associative account of learning and the evolutionary vocation of the ecological approach of learning. Copyright © 2017. Published by Elsevier B.V.

  17. Functional contributions and interactions between the human hippocampus and subregions of the striatum during arbitrary associative learning and memory

    Science.gov (United States)

    Mattfeld, Aaron T.; Stark, Craig E. L.

    2015-01-01

    The hippocampus and striatum are thought to have different functional roles in learning and memory. It is unknown under what experimental conditions their contributions are dissimilar or converge, and the extent to which they interact over the course of learning. In order to evaluate both the functional contributions of as well as the interactions between the human hippocampus and striatum, the present study used high-resolution functional magnetic resonance imaging (fMRI) and variations of a conditional visuomotor associative learning task that either taxed arbitrary associative learning (Experiment 1) or stimulus-response learning (Experiment 2). In the first experiment we observed changes in activity in the hippocampus and anterior caudate that reflect differences between the two regions consistent with distinct computational principles. In the second experiment we observed activity in the putamen that reflected content specific representations during the learning of arbitrary conditional visuomotor associations. In both experiments the hippocampus and ventral striatum demonstrated dynamic functional coupling during the learning of new arbitrary associations, but not during retrieval of well-learned arbitrary associations using control variants of the tasks that did not preferentially tax one system versus the other. These findings suggest that both the hippocampus and subregions of the dorsal striatum contribute uniquely to the learning of arbitrary associations while the hippocampus and ventral striatum interact over the course of learning. PMID:25560298

  18. Team learning and its association with the implementation of competence-based education

    NARCIS (Netherlands)

    Wijnia, L.; Kunst, E.M.; van Woerkom, M.; Poell, R.F.

    2016-01-01

    Competence-based education (CBE) is the leading paradigm for education reform of Vocational Education and Training in European countries. This study addresses the association of collective team identification, task interdependence, team learning, and team size, with the implementation of CBE (N =

  19. Learning Outcomes Associated with Classroom Implementation of a Biotechnology-Themed Video Game

    Science.gov (United States)

    Barko, Tim; Sadler, Troy D.

    2013-01-01

    The educational video game Mission Biotech provides a virtual experience for students in learning biotechnology materials and tools. This study explores the use of Mission Biotech and the associated curriculum by three high school teachers and their students. All three classes demonstrated gains on a curriculum-aligned test of science content.…

  20. Do Psychology Department Mission Statements Reflect the American Psychological Association Undergraduate Learning Goals?

    Science.gov (United States)

    Warchal, Judith R.; Ruiz, Ana I.; You, Di

    2017-01-01

    This study focuses on the inclusion of the American Psychological Association's learning goals in the mission statements of undergraduate psychology programs across the US. We reviewed the mission statements available on websites for 1336 psychology programs listed in the Carnegie classification. Results of a content analysis revealed that of the…

  1. Are Approaches to Learning in Kindergarten Associated with Academic and Social Competence Similarly?

    Science.gov (United States)

    Razza, Rachel A.; Martin, Anne; Brooks-Gunn, Jeanne

    2015-01-01

    Background: Approaches to learning (ATL) is a key domain of school readiness with important implications for children's academic trajectories. Interestingly, however, the impact of early ATL on children's social competence has not been examined. Objective: This study examines associations between children's ATL at age 5 and academic achievement…

  2. Children Learn Spurious Associations in Their Math Textbooks: Examples from Fraction Arithmetic

    Science.gov (United States)

    Braithwaite, David W.; Siegler, Robert S.

    2018-01-01

    Fraction arithmetic is among the most important and difficult topics children encounter in elementary and middle school mathematics. Braithwaite, Pyke, and Siegler (2017) hypothesized that difficulties learning fraction arithmetic often reflect reliance on associative knowledge--rather than understanding of mathematical concepts and procedures--to…

  3. History and Culture of Alara--The Action Learning and Action Research Association

    Science.gov (United States)

    Zuber-Skerritt, Ortrun; Passfield, Ron

    2016-01-01

    As co-founders of the Action Learning and Action Research Association (ALARA), we tell the story of this international network organisation through our personal experience. Our history traces the evolution of ALARA from origins at the first World Congress in 1990 in Brisbane, Australia, through development over two and a half decades, to its…

  4. Association of prenatal alcohol exposure with behavioral and learning problems in early adolescence.

    Science.gov (United States)

    Olson, H C; Streissguth, A P; Sampson, P D; Barr, H M; Bookstein, F L; Thiede, K

    1997-09-01

    To examine the association of moderate levels of prenatal alcohol exposure with learning and behavior in early adolescence. A population-based cohort of 464 children were followed longitudinally from birth to age 14 years. Alcohol exposure was assessed via in-depth maternal self-report in the fifth month of pregnancy. At age 14, learning and behavior were assessed with multiple measures, tapping parent, teenager, and psychologist viewpoints, drawn from adolescent laboratory examination and parent phone interview. The underlying pattern of association between prenatal alcohol and adolescent outcome was detected using partial least-squares statistical techniques; confounding factors were dealt with by regression methods. Analyses revealed a statistically significant, subtle relationship between greater prenatal alcohol use and increased behavior/learning difficulties during adolescence, even after accounting for other developmental influences. "Binge" maternal drinking and exposure early in pregnancy were associated with a profile of adolescent antisocial behavior, school problems, and self-perceived learning difficulties. Fetal alcohol exposure (even at "social drinking" levels) is associated with developmental difficulties in adolescence that are consistent with problems seen earlier in life. Clinicians should understand the potential role prenatal alcohol exposure plays in behavioral and cognitive problems.

  5. Associative Learning Predicts Intelligence above and beyond Working Memory and Processing Speed

    Science.gov (United States)

    Kaufman, Scott Barry; DeYoung, Colin G; Gray, Jeremy R.; Brown, Jamie; Mackintosh, Nicholas

    2009-01-01

    Recent evidence suggests the existence of multiple cognitive mechanisms that support the general cognitive ability factor (g). Working memory and processing speed are the two best established candidate mechanisms. Relatively little attention has been given to the possibility that associative learning is an additional mechanism contributing to g.…

  6. Learning Processes Associated with Panic-Related Symptoms in Families with and without Panic Disordered Mothers

    Science.gov (United States)

    de Albuquerque, Jiske E. G.; Munsch, Simone; Margraf, Jurgen; Schneider, Silvia

    2013-01-01

    The present study compared learning processes associated with panic-related symptoms in families with and without panic disordered mothers. Using a multi-informant approach, 86 mothers [of whom 58 had a primary diagnosis of panic disorder (PD)], their partners and teenage children (mean age, 16.67 years) reported about parents' behavior (modeling…

  7. A World of Learning: Practical Manual. Enhancing the Multiplier Effect of the Associated Schools Project.

    Science.gov (United States)

    United Nations Educational, Scientific, and Cultural Organization, Paris (France).

    This manual presents the major lessons learned about how national authorities, individual institutions, and individual educators can work to increase the impact of the Associated Schools Project (ASP) schools and spread it to other parts of the educational system. ASP is a project of the United Nations Educational, Scientific and Cultural…

  8. Falling into LINE: School Strategies for Overcoming Challenges Associated with Learning in Natural Environments (LINE)

    Science.gov (United States)

    Edwards-Jones, Andrew; Waite, Sue; Passy, Rowena

    2018-01-01

    As the benefits of outdoor learning have become of increasing interest to the education sector, so the importance of understanding and overcoming challenges associated with this pedagogy has gained greater significance. The Natural Connections Demonstration Project recruited primary, secondary, and special schools across south-west England with a…

  9. Physical activity and sedentary behavior associated with learning outcomes and cognition in adult distance learners

    NARCIS (Netherlands)

    Gijselaers, Jérôme; De Groot, Renate; Kirschner, Paul A.

    2013-01-01

    Gijselaers, H. J. M., De Groot, R. H. M., & Kirschner, P. A. (2013, 7 November). Physical activity and sedentary behavior associated with learning outcomes and cognition in adult distance learners. Paper presentation at the ICO [Interuniversity Center for Educational Research] National Fall School,

  10. Associations among Sleep Problems, Learning Difficulties and Substance Use in Adolescence

    Science.gov (United States)

    Fakier, Nuraan; Wild, Lauren G.

    2011-01-01

    This study investigated the relationships among sleep problems, learning difficulties and substance use in adolescence. Previous research suggests that these variables share an association with executive functioning deficits, and are intertwined. The sample comprised 427 adolescents (M age = 16 years) attending remedial schools and 276 adolescents…

  11. Association between mutation spectra and stable and unstable DNA adduct profiles in Salmonella for benzo[a]pyrene and dibenzo[a,l]pyrene

    Energy Technology Data Exchange (ETDEWEB)

    DeMarini, David M., E-mail: demarini.david@epa.gov [Integrated Systems Toxicology Division, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711 (United States); Hanley, Nancy M.; Warren, Sarah H.; Adams, Linda D.; King, Leon C. [Integrated Systems Toxicology Division, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711 (United States)

    2011-09-01

    Highlights: {yields} Benzo[a]pyrene (BP) induces stable DNA adducts and mutations primarily at guanine. {yields} Dibenzo[a,l]pyrene (DBP) induces them primarily at adenine. {yields} BP induces abasic sites, but DBP does not in the Salmonella mutagenicity assay. {yields} Stable DNA adducts alone appear to account for the mutation spectrum of DBP. {yields} Stable DNA adducts and possibly abasic sites account for the mutation spectrum of BP. - Abstract: Benzo[a]pyrene (BP) and dibenzo[a,l]pyrene (DBP) are two polycyclic aromatic hydrocarbons (PAHs) that exhibit distinctly different mutagenicity and carcinogenicity profiles. Although some studies show that these PAHs produce unstable DNA adducts, conflicting data and arguments have been presented regarding the relative roles of these unstable adducts versus stable adducts, as well as oxidative damage, in the mutagenesis and tumor-mutation spectra of these PAHs. However, no study has determined the mutation spectra along with the stable and unstable DNA adducts in the same system with both PAHs. Thus, we determined the mutagenic potencies and mutation spectra of BP and DBP in strains TA98, TA100 and TA104 of Salmonella, and we also measured the levels of abasic sites (aldehydic-site assay) and characterized the stable DNA adducts ({sup 32}P-postlabeling/HPLC) induced by these PAHs in TA104. Our results for the mutation spectra and site specificity of stable adducts were consistent with those from other systems, showing that DBP was more mutagenic than BP in TA98 and TA100. The mutation spectra of DBP and BP were significantly different in TA98 and TA104, with 24% of the mutations induced by BP in TA98 being complex frameshifts, whereas DBP produced hardly any of these mutations. In TA104, BP produced primarily GC to TA transversions, whereas DBP produced primarily AT to TA transversions. The majority (96%) of stable adducts induced by BP were at guanine, whereas the majority (80%) induced by DBP were at adenine

  12. Nicotinic modulation of hippocampal cell signaling and associated effects on learning and memory.

    Science.gov (United States)

    Kutlu, Munir Gunes; Gould, Thomas J

    2016-03-01

    The hippocampus is a key brain structure involved in synaptic plasticity associated with long-term declarative memory formation. Importantly, nicotine and activation of nicotinic acetylcholine receptors (nAChRs) can alter hippocampal plasticity and these changes may occur through modulation of hippocampal kinases and transcription factors. Hippocampal kinases such as cAMP-dependent protein kinase (PKA), calcium/calmodulin-dependent protein kinases (CAMKs), extracellular signal-regulated kinases 1 and 2 (ERK1/2), and c-jun N-terminal kinase 1 (JNK1), and the transcription factor cAMP-response element-binding protein (CREB) that are activated either directly or indirectly by nicotine may modulate hippocampal plasticity and in parallel hippocampus-dependent learning and memory. Evidence suggests that nicotine may alter hippocampus-dependent learning by changing the time and magnitude of activation of kinases and transcription factors normally involved in learning and by recruiting additional cell signaling molecules. Understanding how nicotine alters learning and memory will advance basic understanding of the neural substrates of learning and aid in understanding mental disorders that involve cognitive and learning deficits. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Finding patterns and learning words: Infant phonotactic knowledge is associated with vocabulary size.

    Science.gov (United States)

    Graf Estes, Katharine; Gluck, Stephanie Chen-Wu; Grimm, Kevin J

    2016-06-01

    Native language statistical regularities about allowable phoneme combinations (i.e., phonotactic patterns) may provide learners with cues to support word learning. The current research investigated the association between infants' native language phonotactic knowledge and their word learning progress, as measured by vocabulary size. In the experiment, 19-month-old infants listened to a corpus of nonce words that contained novel phonotactic patterns. All words began with "illegal" consonant clusters that cannot occur in native (English) words. The rationale for the task was that infants with fragile phonotactic knowledge should exhibit stronger learning of the novel illegal phonotactic patterns than infants with robust phonotactic knowledge. We found that infants with smaller vocabularies showed stronger phonotactic learning than infants with larger vocabularies even after accounting for general cognition. We propose that learning about native language structure may promote vocabulary development by providing a foundation for word learning; infants with smaller vocabularies may have weaker support from phonotactics than infants with larger vocabularies. Furthermore, stored vocabulary knowledge may promote the detection of phonotactic patterns even during infancy. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. Association of Medical School Pediatric Department Chairs Principles of Lifelong Learning in Pediatric Medicine.

    Science.gov (United States)

    Opipari, Valerie P; Daniels, Stephen R; Wilmott, Robert W; Jacobs, Richard F

    2016-11-01

    Pediatric general and subspecialty care requires continuous effort to maintain knowledge and competencies in clinical practice. Equally important are efforts by investigators and educators to maintain knowledge and competencies in the conduct of research and training. The Association of Medical School Pediatric Department Chairs initiated a survey in July 2015 to define principles of lifelong learning in pediatric medicine and determine the approaches and strategies used by chairs to assess knowledge and competence across the care, research, and teaching missions. A total of 101 of 142 chairs (71%) completed the survey. Six of 7 proposed principles were endorsed by 84% to 96% of Association of Medical School Pediatric Department Chairs members. The focus areas included individual accountability, individually relevant activities, use of evidence-based guidelines/national standards, gaining cognitive expertise, learning as a continuous effort, affordability, and focus on individual understanding. The chairs endorsed a requirement for evidence of lifelong learning, competence, and compliance by all faculty members in clinical (n = 89 [88%]), research (n = 63 [62%]), and educational (n = 85 [84%]) practice. The survey identified the strategies to assess lifelong learning and faculty competence and compliance in clinical, research, and educational roles. Across missions, chairs endorsed an expectation for individual responsibility supplemented by formal evaluation practices and institutional and regulatory office oversight. While chairs endorsed an important role for the American Board of Pediatrics in assessing and verifying lifelong learning, knowledge, and competence in general and specialty certification, most (n = 91 [90%]) endorsed a need to revise current board requirements to better emphasize closing gaps in knowledge and using approaches that are evidence-based. This study provides the perspectives of pediatric department chairs on principles

  15. Retrospective analysis of the learning curve associated with laparoscopic ovariectomy in dogs and associated perioperative complication rates.

    Science.gov (United States)

    Pope, Juliet Frances Anne; Knowles, Toby Grahame

    2014-08-01

    To assess the learning curve associated with laparoscopic ovariectomy (LOE) in 618 dogs and to report perioperative complication rates. Case series. Dogs (n = 618). Data retrieved from the medical records of bitches admitted for LOE over 42 months included date of surgery, breed, weight (kg), age (months), surgeon, suture material used, intraoperative complications and postoperative complications. Each LOE was defined as "successful" or "unsuccessful" by the absence or presence of an intraoperative complication and "failure" rate described using a CUSUM technique. Follow-up time ranged from 152 to 1,435 days (median, 737 days). Intraoperative complications occurred in 10 dogs (1.6%) and included: splenic laceration (6 dogs; 1%), urinary bladder perforation (3 dogs; 0.5%), and subcutaneous emphysema (1 dog; 0.2%). Postoperative complications occurred in 99 dogs (16%) and included: incisional inflammation treated with antibiotics (87 dogs [14%]; 96/1,854 incisions; 5.1%), incisional seroma (5 dogs [0.8%]; 5/1,854 incisions, 0.3%), incisional hernia (4 dogs [0.6%]; 4/1,854 incisions, 0.2%), and ovarian remnant syndrome (3 dogs; 0.5%). CUSUM charts indicated an initial "learning curve" of ∼80 LOE. LOE is a technique with an initial learning curve but once surgical proficiency is reached after ∼80 procedures then intraoperative complication rates associated with the procedure can be low. © Copyright 2014 by The American College of Veterinary Surgeons.

  16. Positive and negative feedback learning and associated dopamine and serotonin transporter binding after methamphetamine.

    Science.gov (United States)

    Stolyarova, Alexandra; O'Dell, Steve J; Marshall, John F; Izquierdo, Alicia

    2014-09-01

    Learning from mistakes and prospectively adjusting behavior in response to reward feedback is an important facet of performance monitoring. Dopamine (DA) pathways play an important role in feedback learning and a growing literature has also emerged on the importance of serotonin (5HT) in reward learning, particularly during punishment or reward omission (negative feedback). Cognitive impairments resulting from psychostimulant exposure may arise from altered patterns in feedback learning, which in turn may be modulated by DA and 5HT transmission. We analyzed long-term, off-drug changes in learning from positive and negative feedback and associated striatal DA transporter (DAT) and frontocortical 5HT transporter (SERT) binding in rats pretreated with methamphetamine (mAMPH). Specifically, we assessed the reversal phase of pairwise visual discrimination learning in rats receiving single dose- (mAMPHsingle) vs. escalating-dose exposure (mAMPHescal). Using fine-grained trial-by-trial analyses, we found increased sensitivity to and reliance on positive feedback in mAMPH-pretreated animals, with the mAMPHsingle group showing more pronounced use of this type of feedback. In contrast, overall negative feedback sensitivity was not altered following any mAMPH treatment. In addition to validating the enduring effects of mAMPH on early reversal learning, we found more consecutive error commissions before the first correct response in mAMPH-pretreated rats. This behavioral rigidity was negatively correlated with subregional frontocortical SERT whereas positive feedback sensitivity negatively correlated with striatal DAT binding. These results provide new evidence for the overlapping, yet dissociable roles of DA and 5HT systems in overcoming perseveration and in learning new reward rules. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Associative learning during early adulthood enhances later memory retention in honeybees.

    Directory of Open Access Journals (Sweden)

    Andrés Arenas

    Full Text Available BACKGROUND: Cognitive experiences during the early stages of life play an important role in shaping the future behavior in mammals but also in insects, in which precocious learning can directly modify behaviors later in life depending on both the timing and the rearing environment. However, whether olfactory associative learning acquired early in the adult stage of insects affect memorizing of new learning events has not been studied yet. METHODOLOGY: Groups of adult honeybee workers that experienced an odor paired with a sucrose solution 5 to 8 days or 9 to 12 days after emergence were previously exposed to (i a rewarded experience through the offering of scented food, or (ii a non-rewarded experience with a pure volatile compound in the rearing environment. PRINCIPAL FINDINGS: Early rewarded experiences (either at 1-4 or 5-8 days of adult age enhanced retention performance in 9-12-day-conditioned bees when they were tested at 17 days of age. The highest retention levels at this age, which could not be improved with prior rewarded experiences, were found for memories established at 5-8 days of adult age. Associative memories acquired at 9-12 days of age showed a weak effect on retention for some pure pre-exposed volatile compounds; whereas the sole exposure of an odor at any younger age did not promote long-term effects on learning performance. CONCLUSIONS: The associative learning events that occurred a few days after adult emergence improved memorizing in middle-aged bees. In addition, both the timing and the nature of early sensory inputs interact to enhance retention of new learning events acquired later in life, an important matter in the social life of honeybees.

  18. Effect of student emotion-associations on architectural color design of educational spaces in 3D Virtual Learning Environments

    OpenAIRE

    Saleeb, Noha; Dafoulas, George

    2010-01-01

    Research has been previously dedicated to investigating effects of traditional classroom colors on students’ enjoyment, interactions and learning experiences. Students’ emotional reactions towards different colors were also depicted and analyzed. However sparse research has been conducted representing analogous studies of students’ color-emotional associations towards e-learning spaces in 3D virtual learning environments. This study investigates positive and negative emotional associations ex...

  19. Characteristics of health care organizations associated with learning and development: lessons from a pilot study.

    Science.gov (United States)

    Nyström, Monica

    2009-01-01

    Characteristics of health care organizations associated with an ability to learn from experiences and to develop and manage change were explored in this study. Understanding of these characteristics is necessary to identify factors influencing success in learning from the past and achieving future health care quality objectives. A literature review of the quality improvement, strategic organizational development and change management, organizational learning, and microsystems fields identified 20 organizational characteristics, grouped under (a) organizational systems, (b) key actors, and (c) change management processes. Qualitative methods, using interviews, focus group reports, and archival records, were applied to find associations between identified characteristics and 6 Swedish health care units externally evaluated as delivering high-quality care. Strong support for a characteristic was defined as units having more than 4 sources describing the characteristic as an important success factor. Eighteen characteristics had strong support from at least 2 units. The strongest evidence was found for the following: (i) key actors have long-term commitment, provide support, and make sense of ambiguous situations; (ii) organizational systems encourage employee commitment, participation, and involvement; and (iii) change management processes are employed systematically. Based on the results, a new model of "characteristics associated with learning and development in health care organizations" is proposed.

  20. Dissociating Crossmodal and Verbal Demands in Paired Associate Learning (PAL): What Drives the PAL-Reading Relationship?

    Science.gov (United States)

    Litt, Robin A.; de Jong, Peter F.; van Bergen, Elsje; Nation, Kate

    2013-01-01

    Recent research suggests that visual-verbal paired associate learning (PAL) may tap a crossmodal associative learning mechanism that plays a distinct role in reading development. However, evidence from children with dyslexia indicates that deficits in visual-verbal PAL are strongly linked to the verbal demands of the task. The primary aim of this…

  1. Hyper-Binding across Time: Age Differences in the Effect of Temporal Proximity on Paired-Associate Learning

    Science.gov (United States)

    Campbell, Karen L.; Trelle, Alexandra; Hasher, Lynn

    2014-01-01

    Older adults show hyper- (or excessive) binding effects for simultaneously and sequentially presented distraction. Here, we addressed the potential role of hyper-binding in paired-associate learning. Older and younger adults learned a list of word pairs and then received an associative recognition task in which rearranged pairs were formed from…

  2. Framework and catalogue of tools for Participatory monitoring for Farmer Family Learning Groups and Marketing Associations

    DEFF Research Database (Denmark)

    Vaarst, Mette; Nalunga, Jane; Tibasiima, Thaddeo

    2016-01-01

    external facilitators of FFLGs, four FFLG officers from the four organisations in ECOSAF, 21 Marketing Association officers, and staff members and volunteers from NOGAMU, SATNET and Organic Denmark. In the process we have worked together from each our context, and exchanged ideas on farmer group...... of this project (2013-2015) was Farmer Family Learning Groups (FFLG) as a method for developing long-term food security through social capital building. Furthermore, another project based on the FFLG approach but focusing on the formation of Marketing Associations (MAs) contributed to this booklet. This project...... development, participation and monitoring. Participatory monitoring in Farmer Family Learning Groups and Marketing Associations is for the people and the groups who have set goals for themselves and need to monitor themselves whether they are getting closer to the goals which they have set. These groups...

  3. Neural Pattern Similarity in the Left IFG and Fusiform Is Associated with Novel Word Learning

    Science.gov (United States)

    Qu, Jing; Qian, Liu; Chen, Chuansheng; Xue, Gui; Li, Huiling; Xie, Peng; Mei, Leilei

    2017-01-01

    Previous studies have revealed that greater neural pattern similarity across repetitions is associated with better subsequent memory. In this study, we used an artificial language training paradigm and representational similarity analysis to examine whether neural pattern similarity across repetitions before training was associated with post-training behavioral performance. Twenty-four native Chinese speakers were trained to learn a logographic artificial language for 12 days and behavioral performance was recorded using the word naming and picture naming tasks. Participants were scanned while performing a passive viewing task before training, after 4-day training and after 12-day training. Results showed that pattern similarity in the left pars opercularis (PO) and fusiform gyrus (FG) before training was negatively associated with reaction time (RT) in both word naming and picture naming tasks after training. These results suggest that neural pattern similarity is an effective neurofunctional predictor of novel word learning in addition to word memory. PMID:28878640

  4. Neural Pattern Similarity in the Left IFG and Fusiform Is Associated with Novel Word Learning

    Directory of Open Access Journals (Sweden)

    Jing Qu

    2017-08-01

    Full Text Available Previous studies have revealed that greater neural pattern similarity across repetitions is associated with better subsequent memory. In this study, we used an artificial language training paradigm and representational similarity analysis to examine whether neural pattern similarity across repetitions before training was associated with post-training behavioral performance. Twenty-four native Chinese speakers were trained to learn a logographic artificial language for 12 days and behavioral performance was recorded using the word naming and picture naming tasks. Participants were scanned while performing a passive viewing task before training, after 4-day training and after 12-day training. Results showed that pattern similarity in the left pars opercularis (PO and fusiform gyrus (FG before training was negatively associated with reaction time (RT in both word naming and picture naming tasks after training. These results suggest that neural pattern similarity is an effective neurofunctional predictor of novel word learning in addition to word memory.

  5. Medical Student Perceptions of the Learning Environment: Learning Communities Are Associated With a More Positive Learning Environment in a Multi-Institutional Medical School Study.

    Science.gov (United States)

    Smith, Sunny D; Dunham, Lisette; Dekhtyar, Michael; Dinh, An; Lanken, Paul N; Moynahan, Kevin F; Stuber, Margaret L; Skochelak, Susan E

    2016-09-01

    Many medical schools have implemented learning communities (LCs) to improve the learning environment (LE) for students. The authors conducted this study to determine whether a relationship exists between medical student perceptions of the LE and presence of LCs during the preclerkship years. Students from 24 schools participating in the American Medical Association Learning Environment Study completed the 17-item Medical Student Learning Environment Survey (MSLES) at the end of their first and second years of medical school between 2011 and 2013. Mean total MSLES scores and individual item scores at the end of the first and second years in schools with and without LCs were compared with t tests, and effect sizes were calculated. Mixed-effects longitudinal models were used to control for student demographics and random school and student effects on the relationship between LC status and MSLES score. A total of 4,980 students (81% of 6,148 matriculants) from 18 schools with LCs and 6 without LCs participated. Mean [SD] MSLES scores were significantly higher in LC schools compared with non-LC schools at the end of year one (3.72 [0.44] versus 3.57 [0.43], P < .001) and year two (3.69 [0.49] versus 3.42 [0.54], P < .001). The effect size increased from 0.35 (small) at the end of year one to 0.53 (medium) at the end of year two. This large multi-institutional cohort study found that LCs at medical schools were associated with more positive perceptions of the LE by preclerkship students.

  6. Larger error signals in major depression are associated with better avoidance learning

    Directory of Open Access Journals (Sweden)

    James F eCavanagh

    2011-11-01

    Full Text Available The medial prefrontal cortex (mPFC is particularly reactive to signals of error, punishment, and conflict in the service of behavioral adaptation and it is consistently implicated in the etiology of Major Depressive Disorder (MDD. This association makes conceptual sense, given that MDD has been associated with hyper-reactivity in neural systems associated with punishment processing. Yet in practice, depression-related variance in measures of mPFC functioning often fails to relate to performance. For example, neuroelectric reflections of mediofrontal error signals are often found to be larger in MDD, but a deficit in post-error performance suggests that these error signals are not being used to rapidly adapt behavior. Thus, it remains unknown if depression-related variance in error signals reflects a meaningful alteration in the use of error or punishment information. However, larger mediofrontal error signals have also been related to another behavioral tendency: increased accuracy in avoidance learning. The integrity of this error-avoidance system remains untested in MDD. In this study, EEG was recorded as 21 symptomatic, drug-free participants with current or past MDD and 24 control participants performed a probabilistic reinforcement learning task. Depressed participants had larger mPFC EEG responses to error feedback than controls. The direct relationship between error signal amplitudes and avoidance learning accuracy was replicated. Crucially, this relationship was stronger in depressed participants for high conflict lose-lose situations, demonstrating a selective alteration of avoidance learning. This investigation provided evidence that larger error signal amplitudes in depression are associated with increased avoidance learning, identifying a candidate mechanistic model for hypersensitivity to negative outcomes in depression.

  7. stableGP

    Data.gov (United States)

    National Aeronautics and Space Administration — The code in the stableGP package implements Gaussian process calculations using efficient and numerically stable algorithms. Description of the algorithms is in the...

  8. Skin autofluorescence is elevated in patients with stable coronary artery disease and is associated with serum levels of neopterin and the soluble receptor for advanced glycation end products

    NARCIS (Netherlands)

    Mulder, Douwe J.; van Haelst, Paul L.; Gross, Sascha; de Leeuw, Karina; Bijzet, Johannes; Graaff, Reindert; Gans, Rijk O.; Zijlstra, Felix; Smit, Andries J.

    Aims: To investigate whether skin autofluorescence (AF), a non-invasive marker for advanced glycation end products (AGEs), is elevated in stable coronary artery disease (sCAD) and to investigate its relationship with serum levels of the soluble receptor for AGEs (sRAGE), neopterin and C-reactive

  9. Comparative analysis of the heat stable proteome of radicles of Medicago truncatula seeds during germination identifies late embryogenesis abundant proteins associated with desiccation tolerance

    NARCIS (Netherlands)

    Boudet, J.; Buitink, J.; Hoekstra, F.A.; Rogniaux, H.; Larré, C.; Satour, P.; Leprince, O.

    2006-01-01

    A proteomic analysis was performed on the heat stable protein fraction of imbibed radicles of Medicago truncatula seeds to investigate whether proteins can be identified that are specifically linked to desiccation tolerance (DT). Radicles were compared before and after emergence (2.8 mm long) in

  10. The rationale and design of the PERindopril GENEtic association study (PERGENE): a pharmacogenetic analysis of angiotensin-converting enzyme inhibitor therapy in patients with stable coronary artery disease

    NARCIS (Netherlands)

    Brugts, J. J.; de Maat, M. P. M.; Boersma, E.; Witteman, J. C. M.; van Duijn, C.; Uitterlinden, A. G.; Bertrand, M.; Remme, W.; Fox, K.; Ferrari, R.; Danser, A. H. J.; Simoons, M. L.; Remme, W. J.; Aldershville, J.; Hildebrandt, P.; Bassand, J. P.; Cokkinos, D.; Toutouzas, P.; Eha, J.; Erhardt, L.; Erikssen, J.; Grybauskas, R.; Kalnins, U.; Karsch, K.; Sechtem, U.; Keltai, M.; Klein, W.; Luescher, T.; Mulcahy, D.; Nieminen, M.; Oto, A.; Ozsaruhan, O.; Paulus, W.; Providencia, L.; Riecansky, I.; Ruzyllo, W.; Santini, U.; Tavazzi, L.; Soler-Soler, J.; Widimsky, P.; Julian, D.; Dargie, H.; Kobler, W.; Duprez, D.; Steg, G.; Thygesen, K.; Drexel, H.; Gombotz, G.; Stoeckl, G.; Heyndrickx, G. H.; Legrand, V.; Materne, P.; van Mieghem, W.; Bocek, P.; Branny, M.; Cech, M.; Charouzek, J.; Drazka, J.; Fabik, L.; Florian, J.; Francek, L.; Groch, L.; Havranek, P.; Herman, A.; Hradec, J.; Jansky, P.; Jirmar, R.; Jokl, I.; Krejcova, H.; Kvasnak, M.; Maratka, T.; Marcinek, G.; Moravcova, J.; Nedbal, P.; Peterka, K.; Povolny, J.; Rosolova, H.; Semrad, B.; Sochor, K.; Spacek, R.; Spinar, J.; Stipal, R.; Stuchlik, K.; Sulda, M.; Ulman, J.; Vaclavicek, A.; Vojtisek, P.; Bjerregard Andersen, H.; Dorff, B.; Kristensen, K.; Madsen, J. K.; Markenvard, J.; Meibom, J.; Norgaard, A.; Scheibel, M.; Leht, A.; Teesalu, R.; Vahulaa, V.; Itkonen, A.; Juvonen, J.; Karmakoski, J.; Kilkki, E.; Koskela, E.; Kotila, M. J.; Melin, J.; Nieminen, M. S.; Savola, R.; Terho, T.; Voipio Pulkki, L. M.; Apffel, F.; Attali, P.; Baron, B.; Berthier, Y.; Dambrine, P.; Danchin, N.; Decoulx, E.; Deshayes, P.; Fouche, R.; Genest, M.; Godard, S.; Guillot, J. P.; Hanania, G.; Lelguen, C.; Leroy, F.; Mansourati, J.; Mery, D.; Michel, A. N.; Quiret, J. C.; Raynaud, P.; Rondepierre, D.; Roynard, J. L.; van Belle, E.; Veyrat, A.; Gaudron, P.; Karsch, K. R.; Lauer, B.; Rettig Stsrmer, G.; Riessen, R.; Rutsch, W.; Sigel, H. A.; Simon, R.; Stork, S.; von Schacky, C.; Winkelmann, B. R.; Christakos, S.; Feggos, S.; Geleris, P.; Georgiadis, S.; Gialafos, J.; Goudevenos, I.; Kardara, D.; Kardaras, F.; Karidis, C.; Kelesides, C.; Kyriakidis, M.; Koliopoulos, N.; Kremastinos, D.; Liberi, S.; Manolis, A. N.; Pyrgakis, V.; Papasteriadis, E.; Papazoglou, N.; Skoufas, P.; Stamatelopoulos, S.; Stambola, S.; Stavridis, A.; Syribeis, S.; Vardas, P.; Vassiliadis, I.; Voudris, V.; Zacharoulis, A.; Zobolos, S.; Zouras, C.; Berenyi, I.; Bocsa, Z.; Csendes, E.; Edes, I.; Gelesz, E.; Janosi, A.; Kalo, E.; Karpati, P.; Kornel, S.; Pap, I.; Pinter, I.; Polak, G.; Reiber, I.; Rusznak, M.; Simon, A.; Tarjan, J.; Tihanyi, L.; Timar, S.; Toth, K.; Veress, G.; Barton, J.; Crean, P.; Daly, K.; Kearney, P.; Meany, T. B.; Quigley, P.; Azzolini, P.; Barone, G.; Barsotti, A.; Bellone, E.; Borghetti, A.; Branzi, A.; Brunelli, C.; Capponi, E.; Capucci, A.; Casaccia, M.; Casali, G.; Cecchetti, E.; Ceci, V.; Celegon, L.; Chimini, C.; Colombo, A.; Corsini, G.; Cucchini, F.; Dalla Volta, S.; de Luca, I.; de Servi, S.; Delise, P.; Di Donato, M.; Di Giacomo, U.; Di Pasquale, G.; Fiorentini, C.; Gaddi, O.; Giannetto, M.; Giannuzzi, P.; Giordano, A.; Giovannini, E.; Iacono, A.; Inama, G.; Ippoliti, G.; Leghissa, R.; Lorusso, R.; Marzilli, M.; Minutiello, L.; Moretti, G.; Mosele, G. M.; Pasotti, C.; Pettinati, G.; Pezzano, A.; Polimeni, M. R.; Portaluppi, F.; Proto, C.; Riva, S.; Sanguinetti, M.; Santini, M.; Severi, S.; Sinagra, G.; Tantalo, L.; Vajola, S. F.; Vincenzi, M.; Volterrani, M.; Zavatteri, G.; Zogno, M.; Gailiss, E.; Gersamija, A.; Ozolina, M. A.; Skards, J.; Baubiniene, A.; Berukstis, E.; Grigoniene, L.; Grybauskas, A. N.; Kibarskis, A.; Kirkutis, A.; Marcinkus, R.; Milvidaite, I.; Vasiliauskas, D.; Aalders, J. C. A.; Bruggeling, W. A. J.; Bucx, J. J. J.; de Feyter, P. J.; de Leeuw, M. J.; de Waard, D. E. P.; de Weerd, G. J.; de Zwaan, C.; Dijkgraaf, R.; Droste, H. T.; Freericks, M. P.; Hagoort Kok, A. W.; Jap, W. T. J.; Jochemsen, G. M.; Kiemeney, K.; Kuijer, P. J. P.; Mannaerts, H. F. J.; Piek, J. J.; Saelman, J. P. M.; Slob, F. D.; Smits, W. C. G.; Spierenburg, H. A. M.; Suttorp, M. J.; Tan, T. B.; van Beek, G. J.; van Daele, M. E. R. M.; van den Merkhof, L. F. M.; van den Toren, E. W.; van Hessen, M. W. J.; van Langeveld, R. A. M.; van Loo, L. W. H.; van Nierop, P. R.; van Rey, F. J. W.; van Straalen, M. J.; Vos, J.; Werner, H. A.; Westendorp, J. J. C.; Zwiers, G.; Achremczyk, P.; Adamus, J.; Baska, J.; Bolinska Soltysiak, H.; Bubinski, R.; Ceremuzynski, L.; Cieslinski, A.; Dariusz, D.; Deptulski, T.; Drewla, P.; Drozdowski, P.; Dubiel, J. S.; Dudek, D.; Galewicz, M.; Ghlebus, K.; Halawa, B.; Jakubowska Majnigier, M.; Janion, M.; Jaworska, K.; Kaszewska, I.; Kleinrok, A.; Kornacewicz Jach, Z.; Krawczyk, W.; Krynicki, R.; Krzciuk, M.; Krzeminska Pakula, M.

    2009-01-01

    BACKGROUND: Angiotensin-converting enzyme (ACE) inhibitors reduce clinical symptoms and improve outcome in patients with hypertension, heart failure, and stable coronary artery disease (CAD) and are among the most frequently used drugs in these patient groups. For hypertension, treatment is guided

  11. Selectivity in associative learning: A cognitive stage framework for blocking and cue competition phenomena

    Directory of Open Access Journals (Sweden)

    Yannick eBoddez

    2014-11-01

    Full Text Available Blocking is the most important phenomenon in the history of associative learning theory: For over 40 years, blocking has inspired a whole generation of learning models. Blocking is part of a family of effects that are typically termed cue competition effects. Common amongst all cue competition effects is that a cue-outcome relation is poorly learned or poorly expressed because the cue is trained in the presence of an alternative predictor or cause of the outcome. We provide an overview of the cognitive processes involved in cue competition effects in humans and propose a stage framework that brings these processes together. The framework contends that the behavioral display of cue competition is cognitively construed following three stages that include (1 an encoding stage, (2 a retention stage, and (3 a performance stage. We argue that the stage framework supports a comprehensive understanding of cue competition effects.

  12. The real-time learning mechanism of the Scientific Research Associates Advanced Robotic System (SRAARS)

    Science.gov (United States)

    Chen, Alexander Y.

    1990-01-01

    Scientific research associates advanced robotic system (SRAARS) is an intelligent robotic system which has autonomous learning capability in geometric reasoning. The system is equipped with one global intelligence center (GIC) and eight local intelligence centers (LICs). It controls mainly sixteen links with fourteen active joints, which constitute two articulated arms, an extensible lower body, a vision system with two CCD cameras and a mobile base. The on-board knowledge-based system supports the learning controller with model representations of both the robot and the working environment. By consecutive verifying and planning procedures, hypothesis-and-test routines and learning-by-analogy paradigm, the system would autonomously build up its own understanding of the relationship between itself (i.e., the robot) and the focused environment for the purposes of collision avoidance, motion analysis and object manipulation. The intelligence of SRAARS presents a valuable technical advantage to implement robotic systems for space exploration and space station operations.

  13. Associations and propositions: the case for a dual-process account of learning in humans.

    Science.gov (United States)

    McLaren, I P L; Forrest, C L D; McLaren, R P; Jones, F W; Aitken, M R F; Mackintosh, N J

    2014-02-01

    We review evidence that supports the conclusion that people can and do learn in two distinct ways - one associative, the other propositional. No one disputes that we solve problems by testing hypotheses and inducing underlying rules, so the issue amounts to deciding whether there is evidence that we (and other animals) also rely on a simpler, associative system, that detects the frequency of occurrence of different events in our environment and the contingencies between them. There is neuroscientific evidence that associative learning occurs in at least some animals (e.g., Aplysia californica), so it must be the case that associative learning has evolved. Since both associative and propositional theories can in principle account for many instances of successful learning, the problem is then to show that there are at least some cases where the two classes of theory predict different outcomes. We offer a demonstration of cue competition effects in humans under incidental conditions as evidence against the argument that all such effects are based on cognitive inference. The latter supposition would imply that if the necessary information is unavailable to inference then no cue competition should occur. We then discuss the case of unblocking by reinforcer omission, where associative theory predicts an irrational solution to the problem, and consider the phenomenon of the Perruchet effect, in which conscious expectancy and conditioned response dissociate. Further discussion makes use of evidence that people will sometimes provide one solution to a problem when it is presented to them in summary form, and another when they are presented in rapid succession with trial-by trial information. We also demonstrate that people trained on a discrimination may show a peak shift (predicted by associative theory), but given the time and opportunity to detect the relationships between S+ and S-, show rule-based behavior instead. Finally, we conclude by presenting evidence that

  14. Associative Mechanisms Allow for Social Learning and Cultural Transmission of String Pulling in an Insect.

    Science.gov (United States)

    Alem, Sylvain; Perry, Clint J; Zhu, Xingfu; Loukola, Olli J; Ingraham, Thomas; Søvik, Eirik; Chittka, Lars

    2016-10-01

    Social insects make elaborate use of simple mechanisms to achieve seemingly complex behavior and may thus provide a unique resource to discover the basic cognitive elements required for culture, i.e., group-specific behaviors that spread from "innovators" to others in the group via social learning. We first explored whether bumblebees can learn a nonnatural object manipulation task by using string pulling to access a reward that was presented out of reach. Only a small minority "innovated" and solved the task spontaneously, but most bees were able to learn to pull a string when trained in a stepwise manner. In addition, naïve bees learnt the task by observing a trained demonstrator from a distance. Learning the behavior relied on a combination of simple associative mechanisms and trial-and-error learning and did not require "insight": naïve bees failed a "coiled-string experiment," in which they did not receive instant visual feedback of the target moving closer when tugging on the string. In cultural diffusion experiments, the skill spread rapidly from a single knowledgeable individual to the majority of a colony's foragers. We observed that there were several sequential sets ("generations") of learners, so that previously naïve observers could first acquire the technique by interacting with skilled individuals and, subsequently, themselves become demonstrators for the next "generation" of learners, so that the longevity of the skill in the population could outlast the lives of informed foragers. This suggests that, so long as animals have a basic toolkit of associative and motor learning processes, the key ingredients for the cultural spread of unusual skills are already in place and do not require sophisticated cognition.

  15. Multiproxy Holocene paleoclimate records from the southern Peruvian Andes - what new can we learn from the stable carbon isotope composition of high altitude organic matter deposits?

    Science.gov (United States)

    Skrzypek, Grzegorz; Engel, Zbyněk

    2015-04-01

    Interpretation of the Central Andean paleoclimate over the last millennia still represents a research challenge demanding deeper studies [1,2]. Several high-resolution paleoclimate proxies for the last 10,000 years have been developed for the northern hemisphere. However, similar proxies are very limited for South America, particularly for high altitudes where, for example, tree-ring chronologies are not available and instrumental records are very limited. Consequently, our knowledge of high altitude climate changes in arid regions of the Peruvian Andes mainly relies on ice-core and lake deposit studies. In our study, we used a new alternative proxy for interpretation of palaeoclimate conditions based on a peat core taken from the Carhuasanta Valley at the foot of Nevado Mismi in the southern Peruvian Andes (15° 30'S, 71° 43'W, 4809m a.s.l.). The stable carbon isotope composition (δ13C) of Distichia peat reflects mainly the relative variation of the mean air temperature during subsequent growing seasons [3], and allows reconstructions of palaeotemperature changes. In contrast, peat organic carbon concentration (C % wt) records mainly wetness in the valley, directly corresponding to the changes in runoff in the upper part of the catchment. The most prominent climate changes recorded in the peat over last 4ka occurred between 3040 and 2750 cal. yrs BP. The initial warming turned to a very rapid cooling to temperatures at least 2° C lower than the mean for the Late Holocene. Initially drier conditions within this event turned to a short wet phase after 2780 cal. yrs BP, when the temperature increased again. This event coincides with significant changes in peat and ice core records in the Central Andes that match the timing of the global climate event around 2.8 cal. ka BP. Climatic conditions in the study area became relatively dry and stable after the event for about 800 years. Highly variable temperatures and humidity prevailed during the last 2000 years, when

  16. Precise-Spike-Driven Synaptic Plasticity: Learning Hetero-Association of Spatiotemporal Spike Patterns

    Science.gov (United States)

    Yu, Qiang; Tang, Huajin; Tan, Kay Chen; Li, Haizhou

    2013-01-01

    A new learning rule (Precise-Spike-Driven (PSD) Synaptic Plasticity) is proposed for processing and memorizing spatiotemporal patterns. PSD is a supervised learning rule that is analytically derived from the traditional Widrow-Hoff rule and can be used to train neurons to associate an input spatiotemporal spike pattern with a desired spike train. Synaptic adaptation is driven by the error between the desired and the actual output spikes, with positive errors causing long-term potentiation and negative errors causing long-term depression. The amount of modification is proportional to an eligibility trace that is triggered by afferent spikes. The PSD rule is both computationally efficient and biologically plausible. The properties of this learning rule are investigated extensively through experimental simulations, including its learning performance, its generality to different neuron models, its robustness against noisy conditions, its memory capacity, and the effects of its learning parameters. Experimental results show that the PSD rule is capable of spatiotemporal pattern classification, and can even outperform a well studied benchmark algorithm with the proposed relative confidence criterion. The PSD rule is further validated on a practical example of an optical character recognition problem. The results again show that it can achieve a good recognition performance with a proper encoding. Finally, a detailed discussion is provided about the PSD rule and several related algorithms including tempotron, SPAN, Chronotron and ReSuMe. PMID:24223789

  17. Distinct patterns of functional and structural neuroplasticity associated with learning Morse code.

    Science.gov (United States)

    Schmidt-Wilcke, T; Rosengarth, K; Luerding, R; Bogdahn, U; Greenlee, M W

    2010-07-01

    Learning is based on neuroplasticity, i.e. on the capability of the brain to adapt to new experiences. Different mechanisms of neuroplasticity have been described, ranging from synaptic remodeling to changes in complex neural circuitry. To further study the relationship between changes in neural activity and changes in gray matter density associated with learning, we performed a combined longitudinal functional and morphometric magnetic resonance imaging (MRI) study on healthy volunteers who learned to decipher Morse code. We investigated 16 healthy subjects using functional MR imaging (fMRI) and voxel-based morphometry (VBM) before and after they had learned to decipher Morse code. The same set of Morse-code signals was presented to participants pre- and post-training. We found an increase in task-specific neural activity in brain regions known to be critically involved in language perception and memory, such as the inferior parietal cortex bilaterally and the medial parietal cortex during Morse code deciphering. Furthermore we found an increase in gray matter density in the left occipitotemporal region, extending into the fusiform gyrus. Anatomically neighboring sites of functional and structural neuroplasticity were revealed in the left occipitotemporal/inferior temporal cortex, but these regions only marginally overlapped. Implications of this morpho-functional dissociation for learning concepts are discussed. Copyright (c) 2010 Elsevier Inc. All rights reserved.

  18. Precise-spike-driven synaptic plasticity: learning hetero-association of spatiotemporal spike patterns.

    Directory of Open Access Journals (Sweden)

    Qiang Yu

    Full Text Available A new learning rule (Precise-Spike-Driven (PSD Synaptic Plasticity is proposed for processing and memorizing spatiotemporal patterns. PSD is a supervised learning rule that is analytically derived from the traditional Widrow-Hoff rule and can be used to train neurons to associate an input spatiotemporal spike pattern with a desired spike train. Synaptic adaptation is driven by the error between the desired and the actual output spikes, with positive errors causing long-term potentiation and negative errors causing long-term depression. The amount of modification is proportional to an eligibility trace that is triggered by afferent spikes. The PSD rule is both computationally efficient and biologically plausible. The properties of this learning rule are investigated extensively through experimental simulations, including its learning performance, its generality to different neuron models, its robustness against noisy conditions, its memory capacity, and the effects of its learning parameters. Experimental results show that the PSD rule is capable of spatiotemporal pattern classification, and can even outperform a well studied benchmark algorithm with the proposed relative confidence criterion. The PSD rule is further validated on a practical example of an optical character recognition problem. The results again show that it can achieve a good recognition performance with a proper encoding. Finally, a detailed discussion is provided about the PSD rule and several related algorithms including tempotron, SPAN, Chronotron and ReSuMe.

  19. Span: spike pattern association neuron for learning spatio-temporal spike patterns.

    Science.gov (United States)

    Mohemmed, Ammar; Schliebs, Stefan; Matsuda, Satoshi; Kasabov, Nikola

    2012-08-01

    Spiking Neural Networks (SNN) were shown to be suitable tools for the processing of spatio-temporal information. However, due to their inherent complexity, the formulation of efficient supervised learning algorithms for SNN is difficult and remains an important problem in the research area. This article presents SPAN - a spiking neuron that is able to learn associations of arbitrary spike trains in a supervised fashion allowing the processing of spatio-temporal information encoded in the precise timing of spikes. The idea of the proposed algorithm is to transform spike trains during the learning phase into analog signals so that common mathematical operations can be performed on them. Using this conversion, it is possible to apply the well-known Widrow-Hoff rule directly to the transformed spike trains in order to adjust the synaptic weights and to achieve a desired input/output spike behavior of the neuron. In the presented experimental analysis, the proposed learning algorithm is evaluated regarding its learning capabilities, its memory capacity, its robustness to noisy stimuli and its classification performance. Differences and similarities of SPAN regarding two related algorithms, ReSuMe and Chronotron, are discussed.

  20. Precise-spike-driven synaptic plasticity: learning hetero-association of spatiotemporal spike patterns.

    Science.gov (United States)

    Yu, Qiang; Tang, Huajin; Tan, Kay Chen; Li, Haizhou

    2013-01-01

    A new learning rule (Precise-Spike-Driven (PSD) Synaptic Plasticity) is proposed for processing and memorizing spatiotemporal patterns. PSD is a supervised learning rule that is analytically derived from the traditional Widrow-Hoff rule and can be used to train neurons to associate an input spatiotemporal spike pattern with a desired spike train. Synaptic adaptation is driven by the error between the desired and the actual output spikes, with positive errors causing long-term potentiation and negative errors causing long-term depression. The amount of modification is proportional to an eligibility trace that is triggered by afferent spikes. The PSD rule is both computationally efficient and biologically plausible. The properties of this learning rule are investigated extensively through experimental simulations, including its learning performance, its generality to different neuron models, its robustness against noisy conditions, its memory capacity, and the effects of its learning parameters. Experimental results show that the PSD rule is capable of spatiotemporal pattern classification, and can even outperform a well studied benchmark algorithm with the proposed relative confidence criterion. The PSD rule is further validated on a practical example of an optical character recognition problem. The results again show that it can achieve a good recognition performance with a proper encoding. Finally, a detailed discussion is provided about the PSD rule and several related algorithms including tempotron, SPAN, Chronotron and ReSuMe.

  1. Disruption of paired-associate learning in rat offspring perinatally exposed to dioxins.

    Science.gov (United States)

    Kakeyama, Masaki; Endo, Toshihiro; Zhang, Yan; Miyazaki, Wataru; Tohyama, Chiharu

    2014-03-01

    The prevalence of cognitive abnormalities in children has partly been ascribed to environmental chemical exposure. Appropriate animal models and tools for evaluating higher brain function are required to examine this problem. A recently developed behavioral test in which rats learn six unique flavor-location pairs in a test arena was used to evaluate paired-associate learning, a hallmark of the higher cognitive function that is essential to language learning in humans. Pregnant Long-Evans rats were dosed by gavage with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) or 2,3,7,8-tetrabromodibenzo-p-dioxin (TBDD) at a dose of 0, 200, or 800 ng/kg (referred as Control, TCDD-200, TCDD-800, TBDD-200, or TBDD-800, hereafter) on gestational day 15, and the offspring was tested during adulthood. Paired-associate learning was found to be impaired in the TCDD-200 and TBDD-200 groups, but not in either group exposed to 800 ng/kg, the observations of which were ensured by non-cued trials. As for the emotional aspect, during habituation, the TCDD-200 and TBDD-200 groups showed significantly longer latencies to enter the test arena from a start box than the Control, TCDD-800, and TBDD-800 groups, suggesting that the TCDD-200 and TBDD-200 groups manifested anxiety-like behavior. Thus, both the chlorinated dioxin and its brominated congener affected higher brain function to a similar extent in a nearly identical manner. Use of the behavioral test that can evaluate paired-associate learning in rats demonstrated that in utero and lactational exposure to not only TCDD but also TBDD perturbed higher brain function in rat offspring in a nonmonotonic manner.

  2. Differential effects of BDNF val(66)met in repetitive associative learning paradigms.

    Science.gov (United States)

    Freundlieb, Nils; Backhaus, Winifried; Brüggemann, Norbert; Gerloff, Christian; Klein, Christine; Pinnschmidt, Hans O; Hummel, Friedhelm C

    2015-09-01

    In healthy young subjects, the brain derived neurotropic factor (BDNF) val(66)met polymorphism negatively affects behavioural outcome in short-term motor cortex or hippocampus-based learning paradigms. In repetitive training paradigms over several days this effect can be overcome, in tests involving other brain areas even positive effects were found. To further specify the role of this polymorphism in cognitive processes, we used an associative vocabulary learning paradigm over four consecutive days and tested 38 young healthy subjects and 29 healthy elderly subjects. As a control paradigm, we designed a nonverbal haptic Braille letter-learning paradigm based on the same principles. Behavioural outcome was then associated with the BDNF-genotype. In the vocabulary learning task, met carrier (met/val and met/met) benefitted more from the repetitive training than val/val subjects. This was paralleled by a higher reduction of delayed answers during the course of the study, an effect that was also present in the haptic paradigm. However, in a group of healthy elderly subjects, no similar tendency was found. We conclude that the BDNF val(66)met polymorphism alters highly circumscribed answer behaviours in young healthy subjects. This might partly explain the high variability of previously published results. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. Event timing in associative learning: from biochemical reaction dynamics to behavioural observations.

    Directory of Open Access Journals (Sweden)

    Ayse Yarali

    Full Text Available Associative learning relies on event timing. Fruit flies for example, once trained with an odour that precedes electric shock, subsequently avoid this odour (punishment learning; if, on the other hand the odour follows the shock during training, it is approached later on (relief learning. During training, an odour-induced Ca(++ signal and a shock-induced dopaminergic signal converge in the Kenyon cells, synergistically activating a Ca(++-calmodulin-sensitive adenylate cyclase, which likely leads to the synaptic plasticity underlying the conditioned avoidance of the odour. In Aplysia, the effect of serotonin on the corresponding adenylate cyclase is bi-directionally modulated by Ca(++, depending on the relative timing of the two inputs. Using a computational approach, we quantitatively explore this biochemical property of the adenylate cyclase and show that it can generate the effect of event timing on associative learning. We overcome the shortage of behavioural data in Aplysia and biochemical data in Drosophila by combining findings from both systems.

  4. Corticosterone impairs flexible adjustment of spatial navigation in an associative place-reward learning task.

    Science.gov (United States)

    Rusu, Silviu I; Lankelma, Jan V; Jackson, Jadin C; Van Mourik-Donga, Laura A; Joëls, Marian; Pennartz, Cyriel M A

    2018-02-14

    Cognitive challenges are often accompanied by a discharge of stress hormones, which in turn modulate multiple brain areas. Among these, the medial temporal lobe and the prefrontal cortex are critically involved in high-order cognitive functions such as learning, memory, and decision-making. Previous studies assessing the effects of corticosterone on spatial memory found an increase or a decrease in performance depending on the timing of stress hormone discharge relative to the behavioral task. Most of these studies, however, made use of aversively motivated behaviors, whereas less is known about corticosteroid effects on flexible learning during reward-driven spatial navigation. To study how corticosterone modulates flexible spatial learning, we tested rats on a place-reward association task where hormone treatment was administered immediately after a session presenting a change in reward locations. The corticosterone-treated group showed delayed learning during the initial sessions and suboptimal memory consolidation throughout testing. Repeated training on the novel reward positions improved performance and eliminated differences from the control group. We conclude that a marked increase in plasma corticosterone levels immediately after training impairs the flexible formation of new place-reward associations.

  5. The value of a mature, stable, and transparent regulatory framework in facilitating ER programs lessons learned in decommissioning of uranium recovery and other facilities in the USA - 59411

    International Nuclear Information System (INIS)

    McConnell, Keith I.; Camper, Larry

    2012-01-01

    Document available in abstract form only. Full text of publication follows: The history of decommissioning activities in the United States has demonstrated the value of a mature, stable and transparent regulatory framework in facilitating the timely completion of environmental remediation. Two examples are given as case studies. The first example relates to the history of uranium concentrate (yellowcake) production in the U.S. to support the initial development of civilian nuclear power in the U.S. in the 1950's, 60's, 70's and 80's. This yellowcake production, which took place mostly in the western U.S., was undertaken before laws and regulations to prevent contamination and protect public health and safety were fully developed. Significant contamination occurred in terms of both surface and ground water contamination. Although most conventional mills producing uranium during these early years entered decommissioning in the 70's and 80's, the vast majority are still remediating their sites because of persistent contamination in ground water. Had an effective regulatory framework been in place, much of this contamination would have been prevented and remediation accomplished more effectively. In contrast to this experience, a second example is provided related to development of the regulatory framework for decommissioning of non-uranium recovery facilities in the U.S. in the late 1990's and early 2000's

  6. Marine Biogenic Minerals Hold Clues About Changes in Ocean Chemistry and Climate: Some Important Lessons Learned from Studies of Stable and Radioactive Isotopes of Be and Al

    Directory of Open Access Journals (Sweden)

    Devendra Lal

    2002-01-01

    Full Text Available The elements Be and Al exhibit very short residence time in ocean waters, and therefore serve as useful tracers for the study of biogeochemical processes in seawater. A unique feature of these tracers is that nuclear interactions of cosmic rays in the atmosphere produce appreciable amounts of two radioactive isotopes, 10Be (with a half-life of 1.5 my and 26Al (with a half-life of 0.7 my, which are introduced in the hydrosphere, cryosphere, and lithosphere via precipitation. Thus, these elements are labeled by their respective radioactive isotopes, which help quantitative tagging of their biogeochemical cycles. Finally, as we report here, several marine organisms incorporate them in their skeletal shells in certain fixed proportions to their concentrations in the seawater, so that it seems possible to study changes in the ocean chemistry and climate over the past several million years. We summarize here the recent discovery by Dong et al.[9] of significant enrichments of intrinsic Be and Al in marine foraminiferal calcite and coral aragonite, and of Al in opal (radiolarians and aragonite (corals, which should make it possible to determine 10Be/Be and 26Al/Al in oceans in the past. We also summarize their measured 10Be/9Be in foraminiferal calcite in Pacific Ocean cores, which reveal that the concentrations and ratios of the stable and cosmogenic isotopes of Be and Al have varied significantly in the past 30 ky. The implications of these results are discussed.

  7. Head Position Change Is Not Associated with Acute Changes in Bilateral Cerebral Oxygenation in Stable Preterm Infants during the First 3 Days of Life.

    Science.gov (United States)

    Liao, Steve Ming-Che; Rao, Rakesh; Mathur, Amit M

    2015-06-01

    Several recent intraventricular hemorrhage prevention bundles include midline head positioning to prevent potential disturbances in cerebral hemodynamics. We aimed to study the impact of head position change on regional cerebral saturations (SctO2) in preterm infants (position change were compared using paired t-test. In relatively stable preterm infants (gestational age 26.5 ± 1.7 weeks, birth weight 930 ± 220 g; n = 20), bilateral SctO2 remained within normal range (71.1-75.3%) when the head was turned from midline position to either side. Stable preterm infants tolerated brief changes in head position from midline without significant alternation in bilateral SctO2; the impact on critically ill infants needs further evaluation. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  8. Comparing elemental and configural associative theories in human causal learning: a case for attention.

    Science.gov (United States)

    Lachnit, Harald; Schultheis, Holger; König, Stephan; Ungör, Metin; Melchers, Klaus

    2008-04-01

    In two causal learning experiments with human participants, the authors compared various associative theories that assumed either elemental (unique cue, modified unique cue, replaced elements model, and Harris' model) or configural processing of stimuli (Pearce's theory and a modification of it). The authors used modified patterning problems initially suggested by Redhead and Pearce (1995). Predictions for all theories were generated by computer simulations. Both configural theories and the unique cue approach failed to account for the observations. The replaced elements model was able to account for part of the data, but only if the replacement parameters could vary across discrimination problems. The Harris model and the modified unique cue approach, assuming that the salience of stimuli decreases with an increasing number of stimuli in a compound, successfully accounted for all of our data. This success implies that attentional factors should be explicitly taken into account in associative learning theory.

  9. Networks of Learning : Professional Association and the Continuing Education of Teachers of Mathematics in Pakistan

    DEFF Research Database (Denmark)

    Baber, Sikunder Ali

    Importance of the professional development of teachers has been recognized and research has contributed greatly in terms of proposing variety of approaches for the development of teachers,both pre-service and in-service. Among them, networking among teachers, teacher educators,curriculum developers...... and policy makers have been recently receiving attention an innovative and flexible professional development forum for creating ownership among these stakeholders' regarding implementing change and reforms in educational landscape in different countries. The paper draws on the notion of "networking......" and shows how a number of professional associations have become as networks of learning to encourage the continuing professional education of both pre-service and in-service teachers in the context of Pakistan. A case of the Mathematics Association of Pakistan (MAP) as a Network of Learning is presented...

  10. Identification of a mutation associated with permethrin resistance in the para-type sodium channel of the stable fly (Diptera: Muscidae).

    Science.gov (United States)

    Olafson, Pia U; Pitzer, Jimmy B; Kaufman, Phillip E

    2011-02-01

    The insect sodium channel is of particular interest for evaluating resistance to pyrethroids because it is the target molecule for this major class of neurotoxic insecticides. The stable fly, Stomoxys calcitrans (L.) (Diptera: Muscidae), sodium channel coding sequence representing domains IS6 through IVS6 was isolated, and the sequence encoding domain II was compared among individuals of a laboratory strain selected for resistance to permethrin and the unselected, parental generation. A point mutation resulting in a leucine-to-histidine amino acid change was identified (Leul014His), and its location corresponded with that observed for knockdown resistance (kdr) mutations in other insects. As a result, the allele was designated kdr-his. A molecular assay was developed to assess the frequency of this mutation in genomic DNA of individual stable flies from the laboratory selections, which provided further evidence that the kdr-his allele accounts for the observed level ofpermethrin resistance in the selected strain. The assay was then used to evaluate the frequency of the mutation from five field-collected populations originating from three horse farms near Ocala, FL; one horse farm near Gainesville, FL; and one dairy farm near Hague, FL. Frequency of the kdr-his allele ranged from 0.46 to 0.78, supporting further investigation of allele prevalence throughout the stable fly season and in response to field insecticide application.

  11. Synaptic neurotransmission depression in ventral tegmental dopamine neurons and cannabinoid-associated addictive learning.

    Science.gov (United States)

    Liu, Zhiqiang; Han, Jing; Jia, Lintao; Maillet, Jean-Christian; Bai, Guang; Xu, Lin; Jia, Zhengping; Zheng, Qiaohua; Zhang, Wandong; Monette, Robert; Merali, Zul; Zhu, Zhou; Wang, Wei; Ren, Wei; Zhang, Xia

    2010-12-20

    Drug addiction is an association of compulsive drug use with long-term associative learning/memory. Multiple forms of learning/memory are primarily subserved by activity- or experience-dependent synaptic long-term potentiation (LTP) and long-term depression (LTD). Recent studies suggest LTP expression in locally activated glutamate synapses onto dopamine neurons (local Glu-DA synapses) of the midbrain ventral tegmental area (VTA) following a single or chronic exposure to many drugs of abuse, whereas a single exposure to cannabinoid did not significantly affect synaptic plasticity at these synapses. It is unknown whether chronic exposure of cannabis (marijuana or cannabinoids), the most commonly used illicit drug worldwide, induce LTP or LTD at these synapses. More importantly, whether such alterations in VTA synaptic plasticity causatively contribute to drug addictive behavior has not previously been addressed. Here we show in rats that chronic cannabinoid exposure activates VTA cannabinoid CB1 receptors to induce transient neurotransmission depression at VTA local Glu-DA synapses through activation of NMDA receptors and subsequent endocytosis of AMPA receptor GluR2 subunits. A GluR2-derived peptide blocks cannabinoid-induced VTA synaptic depression and conditioned place preference, i.e., learning to associate drug exposure with environmental cues. These data not only provide the first evidence, to our knowledge, that NMDA receptor-dependent synaptic depression at VTA dopamine circuitry requires GluR2 endocytosis, but also suggest an essential contribution of such synaptic depression to cannabinoid-associated addictive learning, in addition to pointing to novel pharmacological strategies for the treatment of cannabis addiction.

  12. Synaptic Neurotransmission Depression in Ventral Tegmental Dopamine Neurons and Cannabinoid-Associated Addictive Learning

    Science.gov (United States)

    Liu, Zhiqiang; Han, Jing; Jia, Lintao; Maillet, Jean-Christian; Bai, Guang; Xu, Lin; Jia, Zhengping; Zheng, Qiaohua; Zhang, Wandong; Monette, Robert; Merali, Zul; Zhu, Zhou; Wang, Wei; Ren, Wei; Zhang, Xia

    2010-01-01

    Drug addiction is an association of compulsive drug use with long-term associative learning/memory. Multiple forms of learning/memory are primarily subserved by activity- or experience-dependent synaptic long-term potentiation (LTP) and long-term depression (LTD). Recent studies suggest LTP expression in locally activated glutamate synapses onto dopamine neurons (local Glu-DA synapses) of the midbrain ventral tegmental area (VTA) following a single or chronic exposure to many drugs of abuse, whereas a single exposure to cannabinoid did not significantly affect synaptic plasticity at these synapses. It is unknown whether chronic exposure of cannabis (marijuana or cannabinoids), the most commonly used illicit drug worldwide, induce LTP or LTD at these synapses. More importantly, whether such alterations in VTA synaptic plasticity causatively contribute to drug addictive behavior has not previously been addressed. Here we show in rats that chronic cannabinoid exposure activates VTA cannabinoid CB1 receptors to induce transient neurotransmission depression at VTA local Glu-DA synapses through activation of NMDA receptors and subsequent endocytosis of AMPA receptor GluR2 subunits. A GluR2-derived peptide blocks cannabinoid-induced VTA synaptic depression and conditioned place preference, i.e., learning to associate drug exposure with environmental cues. These data not only provide the first evidence, to our knowledge, that NMDA receptor-dependent synaptic depression at VTA dopamine circuitry requires GluR2 endocytosis, but also suggest an essential contribution of such synaptic depression to cannabinoid-associated addictive learning, in addition to pointing to novel pharmacological strategies for the treatment of cannabis addiction. PMID:21187978

  13. Fusing Data Mining, Machine Learning and Traditional Statistics to Detect Biomarkers Associated with Depression.

    Directory of Open Access Journals (Sweden)

    Joanna F Dipnall

    Full Text Available Atheoretical large-scale data mining techniques using machine learning algorithms have promise in the analysis of large epidemiological datasets. This study illustrates the use of a hybrid methodology for variable selection that took account of missing data and complex survey design to identify key biomarkers associated with depression from a large epidemiological study.The study used a three-step methodology amalgamating multiple imputation, a machine learning boosted regression algorithm and logistic regression, to identify key biomarkers associated with depression in the National Health and Nutrition Examination Study (2009-2010. Depression was measured using the Patient Health Questionnaire-9 and 67 biomarkers were analysed. Covariates in this study included gender, age, race, smoking, food security, Poverty Income Ratio, Body Mass Index, physical activity, alcohol use, medical conditions and medications. The final imputed weighted multiple logistic regression model included possible confounders and moderators.After the creation of 20 imputation data sets from multiple chained regression sequences, machine learning boosted regression initially identified 21 biomarkers associated with depression. Using traditional logistic regression methods, including controlling for possible confounders and moderators, a final set of three biomarkers were selected. The final three biomarkers from the novel hybrid variable selection methodology were red cell distribution width (OR 1.15; 95% CI 1.01, 1.30, serum glucose (OR 1.01; 95% CI 1.00, 1.01 and total bilirubin (OR 0.12; 95% CI 0.05, 0.28. Significant interactions were found between total bilirubin with Mexican American/Hispanic group (p = 0.016, and current smokers (p<0.001.The systematic use of a hybrid methodology for variable selection, fusing data mining techniques using a machine learning algorithm with traditional statistical modelling, accounted for missing data and complex survey sampling

  14. Synaptic neurotransmission depression in ventral tegmental dopamine neurons and cannabinoid-associated addictive learning.

    Directory of Open Access Journals (Sweden)

    Zhiqiang Liu

    2010-12-01

    Full Text Available Drug addiction is an association of compulsive drug use with long-term associative learning/memory. Multiple forms of learning/memory are primarily subserved by activity- or experience-dependent synaptic long-term potentiation (LTP and long-term depression (LTD. Recent studies suggest LTP expression in locally activated glutamate synapses onto dopamine neurons (local Glu-DA synapses of the midbrain ventral tegmental area (VTA following a single or chronic exposure to many drugs of abuse, whereas a single exposure to cannabinoid did not significantly affect synaptic plasticity at these synapses. It is unknown whether chronic exposure of cannabis (marijuana or cannabinoids, the most commonly used illicit drug worldwide, induce LTP or LTD at these synapses. More importantly, whether such alterations in VTA synaptic plasticity causatively contribute to drug addictive behavior has not previously been addressed. Here we show in rats that chronic cannabinoid exposure activates VTA cannabinoid CB1 receptors to induce transient neurotransmission depression at VTA local Glu-DA synapses through activation of NMDA receptors and subsequent endocytosis of AMPA receptor GluR2 subunits. A GluR2-derived peptide blocks cannabinoid-induced VTA synaptic depression and conditioned place preference, i.e., learning to associate drug exposure with environmental cues. These data not only provide the first evidence, to our knowledge, that NMDA receptor-dependent synaptic depression at VTA dopamine circuitry requires GluR2 endocytosis, but also suggest an essential contribution of such synaptic depression to cannabinoid-associated addictive learning, in addition to pointing to novel pharmacological strategies for the treatment of cannabis addiction.

  15. Visual paired-associate learning: in search of material-specific effects in adult patients who have undergone temporal lobectomy.

    Science.gov (United States)

    Smith, Mary Lou; Bigel, Marla; Miller, Laurie A

    2011-02-01

    The mesial temporal lobes are important for learning arbitrary associations. It has previously been demonstrated that left mesial temporal structures are involved in learning word pairs, but it is not yet known whether comparable lesions in the right temporal lobe impair visually mediated associative learning. Patients who had undergone left (n=16) or right (n=18) temporal lobectomy for relief of intractable epilepsy and healthy controls (n=13) were administered two paired-associate learning tasks assessing their learning and memory of pairs of abstract designs or pairs of symbols in unique locations. Both patient groups had deficits in learning the designs, but only the right temporal group was impaired in recognition. For the symbol location task, differences were not found in learning, but again a recognition deficit was found for the right temporal group. The findings implicate the mesial temporal structures in relational learning. They support a material-specific effect for recognition but not for learning and recall of arbitrary visual and visual-spatial associative information. Copyright © 2010 Elsevier Inc. All rights reserved.

  16. Pavlovian reward learning elicits attentional capture by reward-associated stimuli.

    Science.gov (United States)

    Mine, Chisato; Saiki, Jun

    2018-03-14

    Feature-reward association elicits value-driven attentional capture (VDAC) regardless of the task relevance of associated features. What are the necessary conditions for feature-reward associations in VDAC? Recent studies claim that VDAC is based on Pavlovian conditioning. In this study, we manipulated the temporal relationships among feature, response, and reward in reward learning to elucidate the necessary components of VDAC. We presented reward-associated features in a variety of locations in a flanker task to form a color-reward association (training phase) and then tested VDAC in a subsequent visual search task (test phase). In Experiment 1, we showed reward-associated features in a task display requiring response selection and observed VDAC, consistent with most previous studies. In Experiment 2, features presented at a fixation display before a task display also induced VDAC. Moreover, in Experiment 3, we reduced the time interval between features and rewards so that features appeared after a task display and we obtained marginally significant VDAC. However, no VDAC was observed when features and rewards were simultaneously presented in a feedback display in Experiments 4 and 5, suggesting that a direct association between feature and reward is not sufficient for VDAC. These results are in favor of the idea that response selection does not mediate feature-reward association in VDAC. Moreover, the evidence suggests that the time interval of feature and reward is flexible with some restriction in the learning of feature-reward association. The present study supports the hypothesis that theories of Pavlovian conditioning can account for feature-reward association in VDAC.

  17. Evidence for multiple processes contributing to the Perruchet effect: Response priming and associative learning.

    Science.gov (United States)

    Weidemann, Gabrielle; McAndrew, Amy; Livesey, Evan J; McLaren, Ian P L

    2016-10-01

    The Perruchet effect constitutes a robust demonstration that it is possible to dissociate conditioned responding and expectancy in a random partial reinforcement design across a variety of human associative learning paradigms. This dissociation has been interpreted as providing evidence for multiple processes supporting learning, with expectancy driven by cognitive processes that lead to a Gambler's fallacy, and the pattern of conditioned responding (CRs) the result of an associative learning process. An alternative explanation is that the pattern of CRs is the result of exposure to the unconditioned stimulus (US). In 3 human eyeblink conditioning experiments we examined these competing explanations of the Perruchet effect by employing a differential conditioning design and varying the degree to which the 2 conditioned stimuli (CS) were discriminable. Across all of these experiments there was evidence for a component of the CRs being strongly influenced by recent reinforcement, in a way that was not demonstrably influenced by manipulations of CS discriminability, which suggests a response priming mechanism contributes to the Perruchet effect. However, the complete pattern of results and an analysis of the results from previously published studies are also consistent with there being an associative contribution to the effect. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  18. The speed of learning instructed stimulus-response association rules in human: experimental data and model.

    Science.gov (United States)

    Bugmann, Guido; Goslin, Jeremy; Duchamp-Viret, Patricia

    2013-11-06

    Humans can learn associations between visual stimuli and motor responses from just a single instruction. This is known to be a fast process, but how fast is it? To answer this question, we asked participants to learn a briefly presented (200ms) stimulus-response rule, which they then had to rapidly apply after a variable delay of between 50 and 1300ms. Participants showed a longer response time with increased variability for short delays. The error rate was low and did not vary with the delay, showing that participants were able to encode the rule correctly in less than 250ms. This time is close to the fastest synaptic learning speed deemed possible by diffusive influx of AMPA receptors. Learning continued at a slower pace in the delay period and was fully completed in average 900ms after rule presentation onset, when response latencies dropped to levels consistent with basic reaction times. A neural model was proposed that explains the reduction of response times and of their variability with the delay by (i) a random synaptic learning process that generates weights of average values increasing with the learning time, followed by (ii) random crossing of the firing threshold by a leaky integrate-and-fire neuron model, and (iii) assuming that the behavioural response is initiated when all neurons in a pool of m neurons have fired their first spike after input onset. Values of m=2 or 3 were consistent with the experimental data. The proposed model is the simplest solution consistent with neurophysiological knowledge. Additional experiments are suggested to test the hypothesis underlying the model and also to explore forgetting effects for which there were indications for the longer delay conditions. This article is part of a Special Issue entitled Neural Coding 2012. © 2013 Elsevier B.V. All rights reserved.

  19. Neural compensation in adulthood following very preterm birth demonstrated during a visual paired associates learning task

    Directory of Open Access Journals (Sweden)

    Philip J. Brittain

    2014-01-01

    Full Text Available Very preterm birth (VPT; < 33 weeks of gestation is associated with an increased risk of learning disability, which contributes to more VPT-born children repeating grades and underachieving in school. Learning problems associated with VPT birth may be caused by pathophysiological alterations in neurodevelopment resulting from perinatal brain insult; however, adaptive neuroplastic processes may subsequently occur in the developing preterm brain which ameliorate, to an extent, the potential sequelae of altered neurophysiology. Here, we used functional magnetic resonance imaging (fMRI to compare neuronal activation in 24 VPT individuals and 22 controls (CT in young adulthood during a learning task consisting of the encoding and subsequent recognition of repeated visual paired associates. Structural MRI data were also collected and analysed in order to explore possible structure-function associations. Whilst the two groups did not differ in their learning ability, as demonstrated by their capacity to recognize previously-seen and previously–unseen visual pairs, between-group differences in linear patterns of Blood Oxygenation Level Dependant (BOLD activity were observed across the four repeated blocks of the task for both the encoding and recognition conditions, suggesting that the way learning takes place differs between the two groups. During encoding, significant between-group differences in patterns of BOLD activity were seen in clusters centred on the cerebellum, the anterior cingulate gyrus, the midbrain/substantia nigra, medial temporal (including parahippocampal gyrus and inferior and superior frontal gyri. During the recognition condition, significant between-group differences in patterns of BOLD activity were seen in clusters centred on the claustrum and the posterior cerebellum. Structural analysis revealed smaller grey matter volume in right middle temporal gyrus in VPT individuals compared to controls, however volume in this region

  20. Associative learning as higher order cognition: Learning in human and nonhuman animals from the perspective of propositional theories and relational frame theory.

    Science.gov (United States)

    De Houwer, Jan; Hughes, Sean; Barnes-Holmes, Dermot

    2016-08-01

    We aim to provide a new perspective on the old debate about whether evidence for higher order cognition in nonhuman animals can be reinterpreted in terms of associative learning. Our starting point is the idea that associative learning is best thought of as an effect (i.e., the impact of paired events on behavior) rather than a specific mental process (e.g., the formation of associations). This idea allows us to consider (a) propositional theories according to which associative learning is mediated by higher order mental processes akin to problem solving and (b) relational frame theory that allows one to think of seemingly simple associative learning effects as instances of a complex phenomenon known as arbitrarily applicable relational responding. Based on these 2 theories, we argue that (a) higher order cognition and associative learning are not necessarily mutually exclusive and (b) a more sophisticated conceptualization of higher order cognition is warranted. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  1. Appetitive Olfactory Learning and Long-Term Associative Memory in Caenorhabditis elegans

    Directory of Open Access Journals (Sweden)

    Ichiro N. Maruyama

    2017-05-01

    Full Text Available Because of the relative simplicity of its nervous system, Caenorhabditis elegans is a useful model organism to study learning and memory at cellular and molecular levels. For appetitive conditioning in C. elegans, food has exclusively been used as an unconditioned stimulus (US. It may be difficult to analyze neuronal circuits for associative memory since food is a multimodal combination of olfactory, gustatory, and mechanical stimuli. Here, we report classical appetitive conditioning and associative memory in C. elegans, using 1-nonanol as a conditioned stimulus (CS, and potassium chloride (KCl as a US. Before conditioning, C. elegans innately avoided 1-nonanol, an aversive olfactory stimulus, and was attracted by KCl, an appetitive gustatory stimulus, on assay agar plates. Both massed training without an intertrial interval (ITI and spaced training with a 10-min ITI induced significant levels of memory of association regarding the two chemicals. Memory induced by massed training decayed within 6 h, while that induced by spaced training was retained for more than 6 h. Animals treated with inhibitors of transcription or translation formed the memory induced by spaced training less efficiently than untreated animals, whereas the memory induced by massed training was not significantly affected by such treatments. By definition, therefore, memories induced by massed training and spaced training are classified as short-term memory (STM and long-term memory (LTM, respectively. When animals conditioned by spaced training were exposed to 1-nonanol alone, their learning index was lower than that of untreated animals, suggesting that extinction learning occurs in C. elegans. In support of these results, C. elegans mutants defective in nmr-1, encoding an NMDA receptor subunit, formed both STM and LTM less efficiently than wild-type animals, while mutations in crh-1, encoding a ubiquitous transcription factor CREB required for memory consolidation, affected

  2. Presynaptic GABAB Receptors Regulate Hippocampal Synapses during Associative Learning in Behaving Mice.

    Directory of Open Access Journals (Sweden)

    M Teresa Jurado-Parras

    Full Text Available GABAB receptors are the G-protein-coupled receptors for GABA, the main inhibitory neurotransmitter in the central nervous system. Pharmacological activation of GABAB receptors regulates neurotransmission and neuronal excitability at pre- and postsynaptic sites. Electrophysiological activation of GABAB receptors in brain slices generally requires strong stimulus intensities. This raises the question as to whether behavioral stimuli are strong enough to activate GABAB receptors. Here we show that GABAB1a-/- mice, which constitutively lack presynaptic GABAB receptors at glutamatergic synapses, are impaired in their ability to acquire an operant learning task. In vivo recordings during the operant conditioning reveal a deficit in learning-dependent increases in synaptic strength at CA3-CA1 synapses. Moreover, GABAB1a-/- mice fail to synchronize neuronal activity in the CA1 area during the acquisition process. Our results support that activation of presynaptic hippocampal GABAB receptors is important for acquisition of a learning task and for learning-associated synaptic changes and network dynamics.

  3. Evolution of social learning when high expected payoffs are associated with high risk of failure

    Science.gov (United States)

    Arbilly, Michal; Motro, Uzi; Feldman, Marcus W.; Lotem, Arnon

    2011-01-01

    In an environment where the availability of resources sought by a forager varies greatly, individual foraging is likely to be associated with a high risk of failure. Foragers that learn where the best sources of food are located are likely to develop risk aversion, causing them to avoid the patches that are in fact the best; the result is sub-optimal behaviour. Yet, foragers living in a group may not only learn by themselves, but also by observing others. Using evolutionary agent-based computer simulations of a social foraging game, we show that in an environment where the most productive resources occur with the lowest probability, socially acquired information is strongly favoured over individual experience. While social learning is usually regarded as beneficial because it filters out maladaptive behaviours, the advantage of social learning in a risky environment stems from the fact that it allows risk aversion to be circumvented and the best food source to be revisited despite repeated failures. Our results demonstrate that the consequences of individual risk aversion may be better understood within a social context and suggest one possible explanation for the strong preference for social information over individual experience often observed in both humans and animals. PMID:21508013

  4. Individual differences in task-specific paired associates learning in older adults: the role of processing speed and working memory.

    Science.gov (United States)

    Kurtz, Tanja; Mogle, Jacqueline; Sliwinski, Martin J; Hofer, Scott M

    2013-01-01

    BACKGROUND/STUDY CONTEXT: The role of processing speed and working memory was investigated in terms of individual differences in task-specific paired associates learning in a sample of older adults. Task-specific learning, as distinct from content-oriented item-specific learning, refers to gains in performance due to repeated practice on a learning task in which the to-be-learned material changes over trials. Learning trajectories were modeled within an intensive repeated-measures design based on participants obtained from an opt-in Internet-based sampling service (M(age) = 65.3, SD = 4.81). Participants completed an eight-item paired associates task daily over a 7-day period. Results indicated that a three-parameter hyperbolic model (i.e., initial level, learning rate, and asymptotic performance) best described learning trajectory. After controlling for age-related effects, both higher working memory and higher processing speed had a positive effect on all three learning parameters. These results emphasize the role of cognitive abilities for individual differences in task-specific learning of older adults.

  5. ALOUD biological: Adult Learning Open University Determinants study - Association of biological determinants with study success in formal lifelong learners

    NARCIS (Netherlands)

    Gijselaers, Jérôme; De Groot, Renate; Kirschner, Paul A.

    2012-01-01

    Gijselaers, H. J. M., De Groot, R. H. M., & Kirschner, P. A. (2012, 15 March). ALOUD biological: Adult Learning Open University Determinants study - Association of biological determinants with study success in formal lifelong learners. Presentation given at the plenary meeting of Learning &

  6. Beliefs Associated with Support for Child-Centred Learning Environment among Hong Kong Pre-Service Early Childhood Teachers

    Science.gov (United States)

    Cheung, Sum Kwing; Ling, Elsa Ka-wei; Leung, Suzannie Kit Ying

    2017-01-01

    The physical, social and temporal dimensions of the classroom environment have an important role in children's learning. This study examines the level of support for child-centred learning, and its associated beliefs, that is provided by Hong Kong's pre-service early childhood teachers. Two hundred and seventy-five students from a pre-service…

  7. Learning-Dependent Changes of Associations between Unfamiliar Words and Perceptual Features: A 15-Day Longitudinal Study

    Science.gov (United States)

    Kambara, Toshimune; Tsukiura, Takashi; Shigemune, Yayoi; Kanno, Akitake; Nouchi, Rui; Yomogida, Yukihito; Kawashima, Ryuta

    2013-01-01

    This study examined behavioral changes in 15-day learning of word-picture (WP) and word-sound (WS) associations, using meaningless stimuli. Subjects performed a learning task and two recognition tasks under the WP and WS conditions every day for 15 days. Two main findings emerged from this study. First, behavioral data of recognition accuracy and…

  8. Dreaming of a learning task is associated with enhanced sleep-dependent memory consolidation.

    Science.gov (United States)

    Wamsley, Erin J; Tucker, Matthew; Payne, Jessica D; Benavides, Joseph A; Stickgold, Robert

    2010-05-11

    It is now well established that postlearning sleep is beneficial for human memory performance. Meanwhile, human and animal studies have demonstrated that learning-related neural activity is re-expressed during posttraining nonrapid eye movement (NREM) sleep. NREM sleep processes appear to be particularly beneficial for hippocampus-dependent forms of memory. These observations suggest that learning triggers the reactivation and reorganization of memory traces during sleep, a systems-level process that in turn enhances behavioral performance. Here, we hypothesized that dreaming about a learning experience during NREM sleep would be associated with improved performance on a hippocampus-dependent spatial memory task. Subjects were trained on a virtual navigation task and then retested on the same task 5 hr after initial training. Improved performance at retest was strongly associated with task-related dream imagery during an intervening afternoon nap. Task-related thoughts during wakefulness, in contrast, did not predict improved performance. These observations suggest that sleep-dependent memory consolidation in humans is facilitated by the offline reactivation of recently formed memories, and furthermore that dream experiences reflect this memory processing. That similar effects were not observed during wakefulness suggests that these mnemonic processes are specific to the sleep state. (c) 2010 Elsevier Ltd. All rights reserved.

  9. Health of white sucker within the St. Louis River area of concern associated with habitat usage as assessed using stable isotopes

    Science.gov (United States)

    Blazer, V.S.; Hoffman, J.; Walsh, H.L.; Braham, R.P.; Hahn, C.; Collins, P.; Jorgenson, Z.; Ledder, T.

    2014-01-01

    In Spring 2011, 200 adult white sucker were collected in four areas of the St. Louis River area of concern (AOC), located in Minnesota and Wisconsin, USA. The areas included the upper AOC as a reference area, the upper estuary, St. Louis Bay and Superior Bay. Grossly visible abnormalities were documented and preserved for microscopic analyses, as were five to eight representative pieces of liver tissue. A piece of dorsal muscle was preserved for stable isotope analyses and otoliths removed for age determination. The incidence of raised skin lesions (mucoid plaques) was high (31 %), however, microscopically only 4.5 % of the white suckers had neoplasia (papillomas). The remaining lesions were epidermal hyperplasia. Superior Bay had the lowest percentage of skin/lip lesions (10 %), while St. Louis Bay had the highest (44 %). St. Louis Bay also had the highest incidence of skin neoplasms (12 %). No hepatocellular neoplasms were documented, however bile duct tumors were observed in 4.5 % of the suckers. Foci of cellular alteration were observed in fish from all sites except the upper AOC. Stable isotope data indicated that most of the suckers relied on the St. Louis River AOC for the majority (>75 %) of their diet, indicating they were resident within the AOC and not in Lake Superior. The amount of diet obtained from the upper estuary was a significant predictor of skin lesion incidence. Hence, habitat use within the AOC appears to be an important risk factor for skin and possibly, liver lesions.

  10. Early exposure to volatile anesthetics impairs long-term associative learning and recognition memory.

    Science.gov (United States)

    Lee, Bradley H; Chan, John Thomas; Hazarika, Obhi; Vutskits, Laszlo; Sall, Jeffrey W

    2014-01-01

    Anesthetic exposure early in life affects neural development and long-term cognitive function, but our understanding of the types of memory that are altered is incomplete. Specific cognitive tests in rodents that isolate different memory processes provide a useful approach for gaining insight into this issue. Postnatal day 7 (P7) rats were exposed to either desflurane or isoflurane at 1 Minimum Alveolar Concentration for 4 h. Acute neuronal death was assessed 12 h later in the thalamus, CA1-3 regions of hippocampus, and dentate gyrus. In separate behavioral experiments, beginning at P48, subjects were evaluated in a series of object recognition tests relying on associative learning, as well as social recognition. Exposure to either anesthetic led to a significant increase in neuroapoptosis in each brain region. The extent of neuronal death did not differ between groups. Subjects were unaffected in simple tasks of novel object and object-location recognition. However, anesthetized animals from both groups were impaired in allocentric object-location memory and a more complex task requiring subjects to associate an object with its location and contextual setting. Isoflurane exposure led to additional impairment in object-context association and social memory. Isoflurane and desflurane exposure during development result in deficits in tasks relying on associative learning and recognition memory. Isoflurane may potentially cause worse impairment than desflurane.

  11. Early exposure to volatile anesthetics impairs long-term associative learning and recognition memory.

    Directory of Open Access Journals (Sweden)

    Bradley H Lee

    Full Text Available Anesthetic exposure early in life affects neural development and long-term cognitive function, but our understanding of the types of memory that are altered is incomplete. Specific cognitive tests in rodents that isolate different memory processes provide a useful approach for gaining insight into this issue.Postnatal day 7 (P7 rats were exposed to either desflurane or isoflurane at 1 Minimum Alveolar Concentration for 4 h. Acute neuronal death was assessed 12 h later in the thalamus, CA1-3 regions of hippocampus, and dentate gyrus. In separate behavioral experiments, beginning at P48, subjects were evaluated in a series of object recognition tests relying on associative learning, as well as social recognition.Exposure to either anesthetic led to a significant increase in neuroapoptosis in each brain region. The extent of neuronal death did not differ between groups. Subjects were unaffected in simple tasks of novel object and object-location recognition. However, anesthetized animals from both groups were impaired in allocentric object-location memory and a more complex task requiring subjects to associate an object with its location and contextual setting. Isoflurane exposure led to additional impairment in object-context association and social memory.Isoflurane and desflurane exposure during development result in deficits in tasks relying on associative learning and recognition memory. Isoflurane may potentially cause worse impairment than desflurane.

  12. The Relationship between Associative Learning, Transfer Generalization, and Homocysteine Levels in Mild Cognitive Impairment

    Science.gov (United States)

    Moustafa, Ahmed A.; Hewedi, Doaa H.; Eissa, Abeer M.; Myers, Catherine E.; Sadek, Hisham A.

    2012-01-01

    Previous studies have shown that high total homocysteine levels are associated with Alzheimer's disease (AD) and mild cognitive impairment (MCI). In this study, we test the relationship between cognitive function and total homocysteine levels in healthy subjects (Global Dementia Rating, CDR = 0) and individuals with MCI (CDR = 0.5). We have used a cognitive task that tests learning and generalization of rules, processes that have been previously shown to rely on the integrity of the striatal and hippocampal regions, respectively. We found that total homocysteine levels are higher in MCI individuals than in healthy controls. Unlike what we expected, we found no difference between MCI subjects and healthy controls in learning and generalization. We conducted further analysis after diving MCI subjects in two groups, depending on their Global Deterioration Scale (GDS) scores: individuals with very mild cognitive decline (vMCD, GDS = 2) and mild cognitive decline (MCD, GDS = 3). There was no difference among the two MCI and healthy control groups in learning performance. However, we found that individuals with MCD make more generalization errors than healthy controls and individuals with vMCD. We found no difference in the number of generalization errors between healthy controls and MCI individuals with vMCD. In addition, interestingly, we found that total homocysteine levels correlate positively with generalization errors, but not with learning errors. Our results are in agreement with prior results showing a link between hippocampal function, generalization performance, and total homocysteine levels. Importantly, our study is perhaps among the first to test the relationship between learning (and generalization) of rules and homocysteine levels in healthy controls and individuals with MCI. PMID:23029537

  13. The Transition to Minimal Consciousness through the Evolution of Associative Learning

    Science.gov (United States)

    Bronfman, Zohar Z.; Ginsburg, Simona; Jablonka, Eva

    2016-01-01

    The minimal state of consciousness is sentience. This includes any phenomenal sensory experience – exteroceptive, such as vision and olfaction; interoceptive, such as pain and hunger; or proprioceptive, such as the sense of bodily position and movement. We propose unlimited associative learning (UAL) as the marker of the evolutionary transition to minimal consciousness (or sentience), its phylogenetically earliest sustainable manifestation and the driver of its evolution. We define and describe UAL at the behavioral and functional level and argue that the structural-anatomical implementations of this mode of learning in different taxa entail subjective feelings (sentience). We end with a discussion of the implications of our proposal for the distribution of consciousness in the animal kingdom, suggesting testable predictions, and revisiting the ongoing debate about the function of minimal consciousness in light of our approach. PMID:28066282

  14. The Transition to Minimal Consciousness through the Evolution of Associative Learning.

    Science.gov (United States)

    Bronfman, Zohar Z; Ginsburg, Simona; Jablonka, Eva

    2016-01-01

    The minimal state of consciousness is sentience. This includes any phenomenal sensory experience - exteroceptive, such as vision and olfaction; interoceptive, such as pain and hunger; or proprioceptive, such as the sense of bodily position and movement. We propose unlimited associative learning (UAL) as the marker of the evolutionary transition to minimal consciousness (or sentience) , its phylogenetically earliest sustainable manifestation and the driver of its evolution. We define and describe UAL at the behavioral and functional level and argue that the structural-anatomical implementations of this mode of learning in different taxa entail subjective feelings (sentience). We end with a discussion of the implications of our proposal for the distribution of consciousness in the animal kingdom, suggesting testable predictions, and revisiting the ongoing debate about the function of minimal consciousness in light of our approach.

  15. Learning of arbitrary association between visual and auditory novel stimuli in adults: the "bond effect" of haptic exploration.

    Directory of Open Access Journals (Sweden)

    Benjamin Fredembach

    Full Text Available BACKGROUND: It is well-known that human beings are able to associate stimuli (novel or not perceived in their environment. For example, this ability is used by children in reading acquisition when arbitrary associations between visual and auditory stimuli must be learned. The studies tend to consider it as an "implicit" process triggered by the learning of letter/sound correspondences. The study described in this paper examined whether the addition of the visuo-haptic exploration would help adults to learn more effectively the arbitrary association between visual and auditory novel stimuli. METHODOLOGY/PRINCIPAL FINDINGS: Adults were asked to learn 15 new arbitrary associations between visual stimuli and their corresponding sounds using two learning methods which differed according to the perceptual modalities involved in the exploration of the visual stimuli. Adults used their visual modality in the "classic" learning method and both their visual and haptic modalities in the "multisensory" learning one. After both learning methods, participants showed a similar above-chance ability to recognize the visual and auditory stimuli and the audio-visual associations. However, the ability to recognize the visual-auditory associations was better after the multisensory method than after the classic one. CONCLUSION/SIGNIFICANCE: This study revealed that adults learned more efficiently the arbitrary association between visual and auditory novel stimuli when the visual stimuli were explored with both vision and touch. The results are discussed from the perspective of how they relate to the functional differences of the manual haptic modality and the hypothesis of a "haptic bond" between visual and auditory stimuli.

  16. Factors associated with pharmacy students' attitudes towards learning communication skills - A study among Nordic pharmacy students.

    Science.gov (United States)

    Svensberg, Karin; Brandlistuen, Ragnhild Eek; Björnsdottir, Ingunn; Sporrong, Sofia Kälvemark

    2018-03-01

    Good communication skills are essential for pharmacy students to help patients with their medicines. Students' attitudes towards communication skills learning will influence their willingness to engage in communication training, and their skills when dealing with patients later on in their professional life. The aim of this study was to explore Nordic pharmacy students' attitudes to communication skills learning, and the associations between those attitudes and various student characteristics. A cross-sectional questionnaire-based study was conducted in 11 Nordic pharmacy schools between April 2015 and January 2016. The overall response rate for the final study population was 77% (367 out of 479 students). Pharmacy students who had fulfilled all mandatory communication training and most of their pharmacy practical experience periods were included. The communication skills attitudes scale was the main outcome. Linear regression models were fitted with the outcome variable and various student characteristics as the predictors, using generalized estimating equations to account for clustering within pharmacy schools. Nordic pharmacy students in general have moderately positive attitudes towards learning communication skills. Positive attitudes towards learning communication skills among pharmacy students were associated with being female (β adjusted 0.42, 95% CI 0.20 to 0.63, p communication skills improvement (β adjusted 0.50, 95% CI 0.30 to 0.71, pcommunication skills are not the result of personality (β adjusted  -0.24, 95% CI -0.44 to -0.04, p=0.017). The study provides important information for faculty members responsible for curriculum improvements and teachers to refine their teaching of communication skills. From this, the teaching can be better tailored to suit different students. The students' chances of being able to effectively help patients in the future will be increased by that. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Stable isotopes labelled compounds

    International Nuclear Information System (INIS)

    1982-09-01

    The catalogue on stable isotopes labelled compounds offers deuterium, nitrogen-15, and multiply labelled compounds. It includes: (1) conditions of sale and delivery, (2) the application of stable isotopes, (3) technical information, (4) product specifications, and (5) the complete delivery programme

  18. Stable Boundary Layer Issues

    NARCIS (Netherlands)

    Steeneveld, G.J.

    2012-01-01

    Understanding and prediction of the stable atmospheric boundary layer is a challenging task. Many physical processes are relevant in the stable boundary layer, i.e. turbulence, radiation, land surface coupling, orographic turbulent and gravity wave drag, and land surface heterogeneity. The

  19. Evolutionary Stable Strategy

    Indian Academy of Sciences (India)

    IAS Admin

    After Maynard-Smith and Price [1] mathematically derived why a given behaviour or strategy was adopted by a certain proportion of the population at a given time, it was shown that a strategy which is currently stable in a population need not be stable in evolutionary time (across generations). Additionally it was sug-.

  20. Low Cognitive Impulsivity Is Associated with Better Gain and Loss Learning in a Probabilistic Decision-Making Task

    Science.gov (United States)

    Cáceres, Pablo; San Martín, René

    2017-01-01

    Many advances have been made over the last decades in describing, on the one hand, the link between reward-based learning and decision-making, and on the other hand, the link between impulsivity and decision-making. However, the association between reward-based learning and impulsivity remains poorly understood. In this study, we evaluated the association between individual differences in loss-minimizing and gain-maximizing behavior in a learning-based probabilistic decision-making task and individual differences in cognitive impulsivity. We found that low cognitive impulsivity was associated both with a better performance minimizing losses and maximizing gains during the task. These associations remained significant after controlling for mathematical skills and gender as potential confounders. We discuss potential mechanisms through which cognitive impulsivity might interact with reward-based learning and decision-making. PMID:28261137

  1. Adolescent changes in dopamine D1 receptor expression in orbitofrontal cortex and piriform cortex accompany an associative learning deficit.

    Directory of Open Access Journals (Sweden)

    Anna K Garske

    Full Text Available The orbitofrontal cortex (OFC and piriform cortex are involved in encoding the predictive value of olfactory stimuli in rats, and neural responses to olfactory stimuli in these areas change as associations are learned. This experience-dependent plasticity mirrors task-related changes previously observed in mesocortical dopamine neurons, which have been implicated in learning the predictive value of cues. Although forms of associative learning can be found at all ages, cortical dopamine projections do not mature until after postnatal day 35 in the rat. We hypothesized that these changes in dopamine circuitry during the juvenile and adolescent periods would result in age-dependent differences in learning the predictive value of environmental cues. Using an odor-guided associative learning task, we found that adolescent rats learn the association between an odor and a palatable reward significantly more slowly than either juvenile or adult rats. Further, adolescent rats displayed greater distractibility during the task than either juvenile or adult rats. Using real-time quantitative PCR and immunohistochemical methods, we observed that the behavioral deficit in adolescence coincides with a significant increase in D1 dopamine receptor expression compared to juvenile rats in both the OFC and piriform cortex. Further, we found that both the slower learning and increased distractibility exhibited in adolescence could be alleviated by experience with the association task as a juvenile, or by an acute administration of a low dose of either the dopamine D1 receptor agonist SKF-38393 or the D2 receptor antagonist eticlopride. These results suggest that dopaminergic modulation of cortical function may be important for learning the predictive value of environmental stimuli, and that developmental changes in cortical dopaminergic circuitry may underlie age-related differences in associative learning.

  2. Rapid learning of associations between sound and action through observed movement. A TMS study.

    Science.gov (United States)

    Launay, Jacques; Dean, Roger T; Bailes, Freya

    2016-03-01

    Research has established that there is a cognitive link between perception and production of the same movement. However, there has been relatively little research into the relevance of this for non-expert perceivers, such as music listeners who do not play instruments themselves. In two experiments we tested whether participants can quickly learn new associations between sounds and observed movement without performing those movements themselves. We measured motor evoked potentials (MEPs) in the first dorsal interosseous muscle of participants' right hands while test tones were heard and single transcranial magnetic stimulation (TMS) pulses were used to trigger motor activity. In Experiment 1 participants in a 'human' condition (n=4) learnt to associate the test tone with finger movement of the experimenter, while participants in a 'computer' condition (n=4) learnt that the test tone was triggered by a computer. Participants in the human condition showed a larger increase in MEPs compared with those in the computer condition. In a second experiment pairing between sounds and movement occurred without participants repeatedly observing the movement and we found no such difference between the human (n=4) and computer (n=4) conditions. These results suggest that observers can quickly learn to associate sound with movement, so it should not be necessary to have played an instrument to experience some motor resonance when hearing that instrument.

  3. Protein kinase C activation induces conductance changes in Hermissenda photoreceptors like those seen in associative learning.

    Science.gov (United States)

    Farley, J; Auerbach, S

    Phosphorylation of ion channels has been suggested as one molecular mechanism responsible for learning-produced long-term changes in neuronal excitability. Persistent training-produced changes in two distinct K+ currents (IA (ref. 2), IK-Ca (refs 3,4)) and a voltage-dependent calcium current (ICa; refs 3,4) have previously been shown to occur in type B photoreceptors of Hermissenda, as a result of associative learning. But the identity of the phosphorylation pathway(s) responsible for these changes has not as yet been determined. Injections of cyclic AMP-dependent protein kinase reduce a K+ current (IK) in B cells which is different from those changed by training, but fails to reduce IA and IK-Ca. Phosphorylase b kinase (an exogenous calcium/calmodulin-dependent kinase) reduces IA, but whether IK-Ca and ICa are changed in the manner of associative training is not yet known. Another protein kinase present in high concentrations in both mammalian brain and molluscan nervous systems is protein kinase C, which is both calcium- and phospholipid-sensitive. We now present evidence that activation of protein kinase C by the tumour promoter phorbol ester (PDB) and intracellular injection of the enzyme induce conductance changes similar to those caused by associative training in Hermissenda B cells (that is a reduction of IA and IK-Ca, and enhancement of ICa). These results represent the first direct demonstration that protein kinase C affects membrane K+ ion conductance mechanisms.

  4. Neural compensation in adulthood following very preterm birth demonstrated during a visual paired associates learning task.

    Science.gov (United States)

    Brittain, Philip J; Froudist Walsh, Sean; Nam, Kie-Woo; Giampietro, Vincent; Karolis, Vyacheslav; Murray, Robin M; Bhattacharyya, Sagnik; Kalpakidou, Anastasia; Nosarti, Chiara

    2014-01-01

    Very preterm birth (VPT; brain insult; however, adaptive neuroplastic processes may subsequently occur in the developing preterm brain which ameliorate, to an extent, the potential sequelae of altered neurophysiology. Here, we used functional magnetic resonance imaging (fMRI) to compare neuronal activation in 24 VPT individuals and 22 controls (CT) in young adulthood during a learning task consisting of the encoding and subsequent recognition of repeated visual paired associates. Structural MRI data were also collected and analysed in order to explore possible structure-function associations. Whilst the two groups did not differ in their learning ability, as demonstrated by their capacity to recognize previously-seen and previously-unseen visual pairs, between-group differences in linear patterns of Blood Oxygenation Level Dependant (BOLD) activity were observed across the four repeated blocks of the task for both the encoding and recognition conditions, suggesting that the way learning takes place differs between the two groups. During encoding, significant between-group differences in patterns of BOLD activity were seen in clusters centred on the cerebellum, the anterior cingulate gyrus, the midbrain/substantia nigra, medial temporal (including parahippocampal) gyrus and inferior and superior frontal gyri. During the recognition condition, significant between-group differences in patterns of BOLD activity were seen in clusters centred on the claustrum and the posterior cerebellum. Structural analysis revealed smaller grey matter volume in right middle temporal gyrus in VPT individuals compared to controls, however volume in this region was not significantly associated with functional activation. These results demonstrate that although cognitive task performance between VPT individuals and controls may be comparable on certain measures, differences in BOLD signal may also be evident, some of which could represent compensatory neural processes following VPT

  5. [Optogenetic activation of dorsal hippocampal astrocytic Rac1 blocks the learning of associative memory].

    Science.gov (United States)

    Guo, Xiao-Mu; Liao, Zhao-Hui; Tao, Ye-Zheng; Wang, Fei-Fei; Ma, Lan

    2017-06-25

    Rac1 belongs to the family of Rho GTPases, and plays important roles in the brain function. It affects the cell migration and axon guidance via regulating the cytoskeleton and cellular morphology. However, the effect of its dynamic activation in regulating physiological function remains unclear. Recently, a photoactivatable analogue of Rac1 (PA-Rac1) has been developed, allowing the activation of Rac1 by the specific wavelength of light in living cells. Thus, we constructed recombinant adeno-associated virus (AAV) of PA-Rac1 and its light-insensitive mutant PA-Rac1-C450A under the control of the mouse glial fibrillary acidic protein (mGFAP) promoter to manipulate Rac1 activity in astrocytes by optical stimulation. Primary culture of hippocampal astrocytes was infected with the recombinant AAV-PA-Rac1 or AAV-PA-Rac1-C450A. Real-time fluorescence imaging showed that the cell membrane of the astrocyte expressing PA-Rac1 protruded near the light spot, while the astrocyte expressing PA-Rac1-C450A did not. We injected AAV-PA-Rac1 and AAV-PA-Rac1-C450A into dorsal hippocampus to investigate the role of the activation of Rac1 in regulating the associative learning. With optical stimulation, the PA-Rac1 group, rather than the PA-Rac1-C450A group, showed slower learning curve during the fear conditioning compared with the control group, indicating that activating astrocytic Rac1 blocks the formation of contextual memory. Our data suggest that the activation of Rac1 in dorsal hippocampal astrocyte plays an important role in the associative learning.

  6. Individual personality differences in goats predict their performance in visual learning and non-associative cognitive tasks.

    Science.gov (United States)

    Nawroth, Christian; Prentice, Pamela M; McElligott, Alan G

    2017-01-01

    Variation in common personality traits, such as boldness or exploration, is often associated with risk-reward trade-offs and behavioural flexibility. To date, only a few studies have examined the effects of consistent behavioural traits on both learning and cognition. We investigated whether certain personality traits ('exploration' and 'sociability') of individuals were related to cognitive performance, learning flexibility and learning style in a social ungulate species, the goat (Capra hircus). We also investigated whether a preference for feature cues rather than impaired learning abilities can explain performance variation in a visual discrimination task. We found that personality scores were consistent across time and context. Less explorative goats performed better in a non-associative cognitive task, in which subjects had to follow the trajectory of a hidden object (i.e. testing their ability for object permanence). We also found that less sociable subjects performed better compared to more sociable goats in a visual discrimination task. Good visual learning performance was associated with a preference for feature cues, indicating personality-dependent learning strategies in goats. Our results suggest that personality traits predict the outcome in visual discrimination and non-associative cognitive tasks in goats and that impaired performance in a visual discrimination tasks does not necessarily imply impaired learning capacities, but rather can be explained by a varying preference for feature cues. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Fusing Data Mining, Machine Learning and Traditional Statistics to Detect Biomarkers Associated with Depression

    Science.gov (United States)

    Dipnall, Joanna F.

    2016-01-01

    Background Atheoretical large-scale data mining techniques using machine learning algorithms have promise in the analysis of large epidemiological datasets. This study illustrates the use of a hybrid methodology for variable selection that took account of missing data and complex survey design to identify key biomarkers associated with depression from a large epidemiological study. Methods The study used a three-step methodology amalgamating multiple imputation, a machine learning boosted regression algorithm and logistic regression, to identify key biomarkers associated with depression in the National Health and Nutrition Examination Study (2009–2010). Depression was measured using the Patient Health Questionnaire-9 and 67 biomarkers were analysed. Covariates in this study included gender, age, race, smoking, food security, Poverty Income Ratio, Body Mass Index, physical activity, alcohol use, medical conditions and medications. The final imputed weighted multiple logistic regression model included possible confounders and moderators. Results After the creation of 20 imputation data sets from multiple chained regression sequences, machine learning boosted regression initially identified 21 biomarkers associated with depression. Using traditional logistic regression methods, including controlling for possible confounders and moderators, a final set of three biomarkers were selected. The final three biomarkers from the novel hybrid variable selection methodology were red cell distribution width (OR 1.15; 95% CI 1.01, 1.30), serum glucose (OR 1.01; 95% CI 1.00, 1.01) and total bilirubin (OR 0.12; 95% CI 0.05, 0.28). Significant interactions were found between total bilirubin with Mexican American/Hispanic group (p = 0.016), and current smokers (p<0.001). Conclusion The systematic use of a hybrid methodology for variable selection, fusing data mining techniques using a machine learning algorithm with traditional statistical modelling, accounted for missing data and

  8. Global hypoxia induced impairment in learning and spatial memory is associated with precocious hippocampal aging.

    Science.gov (United States)

    Biswal, Suryanarayan; Sharma, Deepti; Kumar, Kushal; Nag, Tapas Chandra; Barhwal, Kalpana; Hota, Sunil Kumar; Kumar, Bhuvnesh

    2016-09-01

    Both chronological aging and chronic hypoxia stress have been reported to cause degeneration of hippocampal CA3 neurons and spatial memory impairment through independent pathways. However, the possible occurrence of precocious biological aging on exposure to single episode of global hypoxia resulting in impairment of learning and memory remains to be established. The present study thus aimed at bridging this gap in existing literature on hypoxia induced biological aging. Male Sprague Dawley rats were exposed to simulated hypobaric hypoxia (25,000ft) for different durations and were compared with aged rats. Behavioral studies in Morris Water Maze showed decline in learning abilities of both chronologically aged as well as hypoxic rats as evident from increased latency and pathlength to reach target platform. These behavioral changes in rats exposed to global hypoxia were associated with deposition of lipofuscin and ultrastructural changes in the mitochondria of hippocampal neurons that serve as hallmarks of aging. A single episode of chronic hypobaric hypoxia exposure also resulted in the up-regulation of pro-aging protein, S100A9 and down regulation of Tau, SNAP25, APOE and Sod2 in the hippocampus similar to that in aged rats indicating hypoxia induced accelerated aging. The present study therefore provides evidence for role of biological aging of hippocampal neurons in hypoxia induced impairment of learning and memory. Copyright © 2016. Published by Elsevier Inc.

  9. Long-term associative learning predicts verbal short-term memory performance.

    Science.gov (United States)

    Jones, Gary; Macken, Bill

    2018-02-01

    Studies using tests such as digit span and nonword repetition have implicated short-term memory across a range of developmental domains. Such tests ostensibly assess specialized processes for the short-term manipulation and maintenance of information that are often argued to enable long-term learning. However, there is considerable evidence for an influence of long-term linguistic learning on performance in short-term memory tasks that brings into question the role of a specialized short-term memory system separate from long-term knowledge. Using natural language corpora, we show experimentally and computationally that performance on three widely used measures of short-term memory (digit span, nonword repetition, and sentence recall) can be predicted from simple associative learning operating on the linguistic environment to which a typical child may have been exposed. The findings support the broad view that short-term verbal memory performance reflects the application of long-term language knowledge to the experimental setting.

  10. Dopamine Regulates Aversive Contextual Learning and Associated In Vivo Synaptic Plasticity in the Hippocampus

    Directory of Open Access Journals (Sweden)

    John I. Broussard

    2016-03-01

    Full Text Available Dopamine release during reward-driven behaviors influences synaptic plasticity. However, dopamine innervation and release in the hippocampus and its role during aversive behaviors are controversial. Here, we show that in vivo hippocampal synaptic plasticity in the CA3-CA1 circuit underlies contextual learning during inhibitory avoidance (IA training. Immunohistochemistry and molecular techniques verified sparse dopaminergic innervation of the hippocampus from the midbrain. The long-term synaptic potentiation (LTP underlying the learning of IA was assessed with a D1-like dopamine receptor agonist or antagonist in ex vivo hippocampal slices and in vivo in freely moving mice. Inhibition of D1-like dopamine receptors impaired memory of the IA task and prevented the training-induced enhancement of both ex vivo and in vivo LTP induction. The results indicate that dopamine-receptor signaling during an aversive contextual task regulates aversive memory retention and regulates associated synaptic mechanisms in the hippocampus that likely underlie learning.

  11. Distinct effects of dopamine vs STN stimulation therapies in associative learning and retention in Parkinson disease.

    Science.gov (United States)

    Ventre-Dominey, Jocelyne; Mollion, Hélène; Thobois, Stephane; Broussolle, Emmanuel

    2016-04-01

    Evidence has been provided in Parkinson's disease patients of cognitive impairments including visual memory and learning which can be partially compensated by dopamine medication or subthalamic nucleus stimulation. The effects of these two therapies can differ according to the learning processes involving the dorsal vs ventral part of the striatum. Here we aimed to investigate and compare the outcomes of dopamine vs stimulation treatment in Parkinson patient's ability to acquire and maintain over successive days their performance in visual working memory. Parkinson patients performed conditional associative learning embedded in visual (spatial and non spatial) working memory tasks over two consecutive days either ON or OFF dopaminergic drugs or STN stimulation depending on the group of patients studied. While Parkinson patients were more accurate and faster in memory tasks ON vs OFF stimulation independent of the day of testing, performance in medicated patients differed depending on the medication status during the initial task acquisition. Patients who learnt the task ON medication the first day were able to maintain or even improve their memory performance both OFF and ON medication on the second day after consolidation. These effects were observed only in patients with dopamine replacement with or without motor fluctuations. This enhancement in memory performance after having learnt under dopamine medication and not under STN stimulation was mostly significant in visuo-spatial working memory tasks suggesting that dopamine replacement in the depleted dorsal striatum is essential for retention and consolidation of learnt skill. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Explaining Compound Generalization in Associative and Causal Learning Through Rational Principles of Dimensional Generalization

    Science.gov (United States)

    Soto, Fabian A.; Gershman, Samuel J.; Niv, Yael

    2014-01-01

    How do we apply learning from one situation to a similar, but not identical, situation? The principles governing the extent to which animals and humans generalize what they have learned about certain stimuli to novel compounds containing those stimuli vary depending on a number of factors. Perhaps the best studied among these factors is the type of stimuli used to generate compounds. One prominent hypothesis is that different generalization principles apply depending on whether the stimuli in a compound are similar or dissimilar to each other. However, the results of many experiments cannot be explained by this hypothesis. Here we propose a rational Bayesian theory of compound generalization that uses the notion of consequential regions, first developed in the context of rational theories of multidimensional generalization, to explain the effects of stimulus factors on compound generalization. The model explains a large number of results from the compound generalization literature, including the influence of stimulus modality and spatial contiguity on the summation effect, the lack of influence of stimulus factors on summation with a recovered inhibitor, the effect of spatial position of stimuli on the blocking effect, the asymmetrical generalization decrement in overshadowing and external inhibition, and the conditions leading to a reliable external inhibition effect. By integrating rational theories of compound and dimensional generalization, our model provides the first comprehensive computational account of the effects of stimulus factors on compound generalization, including spatial and temporal contiguity between components, which have posed longstanding problems for rational theories of associative and causal learning. PMID:25090430

  13. Reversal learning strategy in adolescence is associated with prefrontal cortex activation.

    Science.gov (United States)

    Boehme, Rebecca; Lorenz, Robert C; Gleich, Tobias; Romund, Lydia; Pelz, Patricia; Golde, Sabrina; Flemming, Eva; Wold, Andrew; Deserno, Lorenz; Behr, Joachim; Raufelder, Diana; Heinz, Andreas; Beck, Anne

    2017-01-01

    Adolescence is a critical maturation period for human cognitive control and executive function. In this study, a large sample of adolescents (n = 85) performed a reversal learning task during functional magnetic resonance imaging. We analyzed behavioral data using a reinforcement learning model to provide individually fitted parameters and imaging data with regard to reward prediction errors (PE). Following a model-based approach, we formed two groups depending on whether individuals tended to update expectations predominantly for the chosen stimulus or also for the unchosen one. These groups significantly differed in their problem behavior score obtained using the child behavior checklist (CBCL) and in a measure of their developmental stage. Imaging results showed that dorsolateral striatal areas covaried with PE. Participants who relied less on learning based on task structure showed less prefrontal activation compared with participants who relied more on task structure. An exploratory analysis revealed that PE-related activity was associated with pubertal development in prefrontal areas, insula and anterior cingulate. These findings support the hypothesis that the prefrontal cortex is implicated in mediating flexible goal-directed behavioral control. © 2016 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  14. Predicting central line-associated bloodstream infections and mortality using supervised machine learning.

    Science.gov (United States)

    Parreco, Joshua P; Hidalgo, Antonio E; Badilla, Alejandro D; Ilyas, Omar; Rattan, Rishi

    2018-02-21

    The purpose of this study was to compare machine learning techniques for predicting central line-associated bloodstream infection (CLABSI). The Multiparameter Intelligent Monitoring in Intensive Care III database was queried for all ICU admissions. The variables included six different severities of illness scores calculated on the first day of ICU admission with their components and comorbidities. The outcomes of interest were in-hospital mortality, central line placement, and CLABSI. Predictive models were created for these outcomes using classifiers with different algorithms: logistic regression, gradient boosted trees, and deep learning. There were 57,786 total hospital admissions and the mortality rate was 10.1%. There were 38.4% patients with a central line and the rate of CLABSI was 1.5%. The classifiers using deep learning performed with the highest AUC for mortality, 0.885±0.010 (p<0.01) and central line placement, 0.816±0.006 (p<0.01). The classifier using logistic regression for predicting CLABSI performed with an AUC of 0.722±0.048 (p<0.01). This study demonstrates models for identifying patients who will develop CLABSI. Early identification of these patients has implications for quality, cost, and outcome improvements. Copyright © 2018 Elsevier Inc. All rights reserved.

  15. Group social rank is associated with performance on a spatial learning task.

    Science.gov (United States)

    Langley, Ellis J G; van Horik, Jayden O; Whiteside, Mark A; Madden, Joah R

    2018-02-01

    Dominant individuals differ from subordinates in their performances on cognitive tasks across a suite of taxa. Previous studies often only consider dyadic relationships, rather than the more ecologically relevant social hierarchies or networks, hence failing to account for how dyadic relationships may be adjusted within larger social groups. We used a novel statistical method: randomized Elo-ratings, to infer the social hierarchy of 18 male pheasants, Phasianus colchicus , while in a captive, mixed-sex group with a linear hierarchy. We assayed individual learning performance of these males on a binary spatial discrimination task to investigate whether inter-individual variation in performance is associated with group social rank. Task performance improved with increasing trial number and was positively related to social rank, with higher ranking males showing greater levels of success. Motivation to participate in the task was not related to social rank or task performance, thus indicating that these rank-related differences are not a consequence of differences in motivation to complete the task. Our results provide important information about how variation in cognitive performance relates to an individual's social rank within a group. Whether the social environment causes differences in learning performance or instead, inherent differences in learning ability predetermine rank remains to be tested.

  16. COMT Val158Met genotype is associated with reward learning: A replication study and meta-analysis

    Science.gov (United States)

    Corral-Frías, Nadia S.; Pizzagalli, Diego A.; Carré, Justin; Michalski, Lindsay J; Nikolova, Yuliya S.; Perlis, Roy H.; Fagerness, Jesen; Lee, Mary R.; Conley, Emily Drabant; Lancaster, Thomas M.; Haddad, Stephen; Wolf, Aaron; Smoller, Jordan W.; Hariri, Ahmad R.; Bogdan, Ryan

    2016-01-01

    Identifying mechanisms through which individual differences in reward learning emerge offers an opportunity to understand both a fundamental form of adaptive responding as well as etiological pathways through which aberrant reward learning may contribute to maladaptive behaviors and psychopathology. One candidate mechanism through which individual differences in reward learning may emerge is variability in dopaminergic reinforcement signaling. A common functional polymorphism within the catechol-O-methyl transferase gene (COMT; rs4680, Val158Met) has been linked to reward learning where homozygosity for the Met allele (associated with heightened prefrontal dopamine function and decreased dopamine synthesis in the midbrain) has been associated with relatively increased reward learning. Here, we used a probabilistic reward learning task to asses response bias, a behavioral form of reward learning, across 3 separate samples that were combined for analyses (age: 21.80 ± 3.95; n=392; 268 female; European-American, n=208). We replicate prior reports that COMT rs4680 Met allele homozygosity is associated with increased reward learning in European-American participants (β=0.20, t= 2.75, p< 0.01; ΔR2= 0.04). Moreover, a meta-analysis of 4 studies, including the current one, confirmed the association between COMT rs4680 genotype and reward learning (95% CI −0.11 to −0.03; z=3.2; p<0.01). These results suggest that variability in dopamine signaling associated with COMT rs4680 influences individual differences in reward which may potentially contribute to psychopathology characterized by reward dysfunction. PMID:27138112

  17. Normal modified stable processes

    DEFF Research Database (Denmark)

    Barndorff-Nielsen, Ole Eiler; Shephard, N.

    2002-01-01

    This paper discusses two classes of distributions, and stochastic processes derived from them: modified stable (MS) laws and normal modified stable (NMS) laws. This extends corresponding results for the generalised inverse Gaussian (GIG) and generalised hyperbolic (GH) or normal generalised inverse...... Gaussian (NGIG) laws. The wider framework thus established provides, in particular, for added flexibility in the modelling of the dynamics of financial time series, of importance especially as regards OU based stochastic volatility models for equities. In the special case of the tempered stable OU process...

  18. Applications of stable isotopes

    International Nuclear Information System (INIS)

    Letolle, R.; Mariotti, A.; Bariac, T.

    1991-06-01

    This report reviews the historical background and the properties of stable isotopes, the methods used for their measurement (mass spectrometry and others), the present technics for isotope enrichment and separation, and at last the various present and foreseeable application (in nuclear energy, physical and chemical research, materials industry and research; tracing in industrial, medical and agronomical tests; the use of natural isotope variations for environmental studies, agronomy, natural resources appraising: water, minerals, energy). Some new possibilities in the use of stable isotope are offered. A last chapter gives the present state and forecast development of stable isotope uses in France and Europe

  19. Associations between otitis media and child behavioural and learning difficulties: Results from a Danish cohort.

    Science.gov (United States)

    Niclasen, J; Obel, C; Homøe, P; Kørvel-Hanquist, A; Dammeyer, J

    2016-05-01

    Findings from studies investigating early childhood episodes of otitis media (OM) and developmental outcomes are inconclusive. This may in part be because large-scale prospective studies controlling for relevant confounding factors are sparse. The present study investigates associations between OM in early childhood and later behavioural and learning difficulties controlling for relevant confounding factors. The study applied data from the Aarhus Birth Cohort's 10-12-year-old follow-up (N=7578). Associations between retrospective parent-reported OM (no OM; 1-3 episodes of OM with/without tympanostomy tubes; 4+ OM episodes without tympanostomy tubes and; 4+ OM episodes with tympanostomy tubes) one the one hand, and parent- and teacher-reported scores on the Strengths and Difficulties Questionnaire (SDQ) and parent-reported academic difficulties on the other hand, were investigated. The following variables were controlled for: parental educational level, maternal and paternal school problems, parental post-natal smoking, breastfeeding, and age at which the child started walking. All analyses were stratified by gender. Large differences in background characteristics were observed for the group of children with 4+ OM episodes with tympanostomy tubes compared to the no OM group. After controlling for relevant confounders, negative associations were consistently observed for the group of children with 4+ episodes of OM with tympanostomy tubes compared to the group of children without OM. This was particularly so for girls. The findings suggest an association between 4+ episodes of early OM with tympanostomy tubes and behavioural and learning difficulties later in childhood. The large inter-group differences, i.e. impact of residual and unmeasured confounding factors, may in part explain the observed associations and underline the need to include these in future studies. Copyright © 2016. Published by Elsevier Ireland Ltd.

  20. Chromosomes A07 and A05 associated with stable and major QTLs for pod weight and size in cultivated peanut (Arachis hypogaea L.).

    Science.gov (United States)

    Luo, Huaiyong; Guo, Jianbin; Ren, Xiaoping; Chen, Weigang; Huang, Li; Zhou, Xiaojing; Chen, Yuning; Liu, Nian; Xiong, Fei; Lei, Yong; Liao, Boshou; Jiang, Huifang

    2018-02-01

    Co-localized intervals and candidate genes were identified for major and stable QTLs controlling pod weight and size on chromosomes A07 and A05 in an RIL population across four environments. Cultivated peanut (Arachis hypogaea L.) is an important legume crops grown in > 100 countries. Hundred-pod weight (HPW) is an important yield trait in peanut, but its underlying genetic mechanism was not well studied. In this study, a mapping population (Xuhua 13 × Zhonghua 6) with 187 recombinant inbred lines (RILs) was developed to map quantitative trait loci (QTLs) for HPW together with pod length (PL) and pod width (PW) by both unconditional and conditional QTL analyses. A genetic map covering 1756.48 cM was constructed with 817 markers. Additive effects, epistatic interactions, and genotype-by-environment interactions were analyzed using the phenotyping data generated across four environments. Twelve additive QTLs were identified on chromosomes A05, A07, and A08 by unconditional analysis, and five of them (qPLA07, qPLA05.1, qPWA07, qHPWA07.1, and qHPWA05.2) showed major and stable expressions in all environments. Conditional QTL mapping found that PL had stronger influences on HPW than PW. Notably, qHPWA07.1, qPLA07, and qPWA07 that explained 17.93-43.63% of the phenotypic variations of the three traits were co-localized in a 5 cM interval (1.48 Mb in physical map) on chromosome A07 with 147 candidate genes related to catalytic activity and metabolic process. In addition, qHPWA05.2 and qPLA05.1 were co-localized with minor QTL qPWA05.2 to a 1.3 cM genetic interval (280 kb in physical map) on chromosome A05 with 12 candidate genes. This study provides a comprehensive characterization of the genetic components controlling pod weight and size as well as candidate QTLs and genes for improving pod yield in future peanut breeding.

  1. Individual differences in personality in laying hens are related to learning a colour cue association.

    Science.gov (United States)

    de Haas, Elske N; Lee, Caroline; Hernandez, Carlos E; Naguib, Marc; Rodenburg, T Bas

    2017-01-01

    Personality can influence how animals perceive and learn cues. The behaviour and physiological responses animals show during stressful events is indicative of their personality. Acute induced stress prior to a cognitive test are known to affect the judgement of a stimulus, but personality of an individual could also affect learning of a specific cognitive paradigm. Here, we assessed if adult laying hens' behaviour and physiological responses, as indicators of their personality, were related to their cognitive performance. We assessed their behavioural responses to a tonic immobility test, an open field test, and a manual restraint test, and measured plasma corticosterone levels after manual restraint. After that, hens (n=20) were trained in a pre-set training schedule to associate a colour-cue with a reward. In a two-choice go-go test, hens needed to choose between a baited or non-baited food container displayed randomly on the left or right side of an arena. Success in learning was related to personality, with better performance of hens which showed a reactive personality type by a long latency to walk, struggle or vocalize during the tests. Only eight out of 20 hens reached the training criteria. The non-learners showed a strong side preference during all training days. Side preferences were strong in hens with high levels of plasma corticosterone and with a long duration of tonic immobility, indicating that fearful, stress-sensitive hens are more prone to develop side biases. Our results show that learning can be hindered by side biases, and fearful animals with a more proactive personality type are more sensitive to develop such biases. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Health Professions Students’ Lifelong Learning Orientation: Associations with Information Skills and Self Efficacy

    Directory of Open Access Journals (Sweden)

    Misa Mi

    2016-04-01

    Full Text Available Objective – This study aimed to investigate the relationships among health professions students’ lifelong learning orientation, self-assessed information skills, and information self-efficacy. Methods – This was a descriptive study with a cross-sectional research design. Participants included 850 nursing students and 325 medical students. A total of 419 students responded to a survey questionnaire that was comprised of 3 parts: demographic information, the Jefferson Scale of Lifelong Learning (JeffSLL-HPS, and an information self-efficacy scale. Results – Findings of the study show a significant correlation between students’ lifelong learning orientation and information self-efficacy. Average JeffSLL-HPS total scores for undergraduate nursing students (M = 41.84 were significantly lower than the scores for graduate nursing students (M = 46.20. Average information self-efficacy total scores were significantly lower for undergraduate nursing students (M = 63.34 than the scores for graduate nursing students (M = 65.97. There were no significant differences among cohorts of medical students for JeffSLL-HPS total scores. However, for information self-efficacy, first year medical students (M = 55.62 and second year medical students (M = 58.00 had significantly lower scores than third/fourth year students (M = 64.42. Conclusion – Findings from the study suggest implications for librarians seeking ways to advance the value and utility of information literacy instruction in educational curricula. As such instruction has the potential to lead to high levels of information self-efficacy associated with lifelong learning; various strategies could be developed and incorporated into the instruction to cultivate students’ information self-efficacy.

  3. Analysing Stable Time Series

    National Research Council Canada - National Science Library

    Adler, Robert

    1997-01-01

    We describe how to take a stable, ARMA, time series through the various stages of model identification, parameter estimation, and diagnostic checking, and accompany the discussion with a goodly number...

  4. The effects of vitamin C on hypothyroidism-associated learning and memory impairment in juvenile rats.

    Science.gov (United States)

    Beheshti, Farimah; Karimi, Sareh; Vafaee, Farzaneh; Shafei, Mohammad Naser; Sadeghnia, Hamid Reza; Hadjzadeh, Mosa Al Reza; Hosseini, Mahmoud

    2017-06-01

    In this study the effects of Vitamin C (Vit C) on hypothyroidism-associated learning and memory impairment in juvenile rats was investigated. The pregnant rats were kept in separate cages. After delivery, they were randomly divided into six groups and treated: (1) Control; (2) Propylthiouracil (PTU) which 0.005% PTU in their drinking; (3-5) Propylthiouracil- Vit C groups; besides PTU, dams in these groups received 10, 100 and 500 mg/kg Vit C respectively, (6) one group as a positive control; the intact rats received an effective dose, 100 mg/kg Vit. C. After delivery, the pups were continued to receive the experimental treatments in their drinking water up to 56th day of their life. Ten male offspring of each group were randomly selected and tested in the Morris water maze (MWM) and passive avoidance (PA) which were started at 63th day (one week after stopping of the treatments). Brains were then removed for biochemical measurements. PTU increased time latency and traveled distance during 5 days in MWM while, reduced the spent time in target quadrant in MWM and step-trough latency (STL) in PA. PTU decreased thiol content, superoxide dismutase (SOD) and catalase (CAT) activities in the brain while, increased molondialdehyde (MDA). In MWM test, 10, 100 and 500 mg/kg Vit C reduced time latency and traveled distance without affecting the traveling speed during 5 days. All doses of Vit C increased the spent time in target quadrant in probe trail of MWM and also increased STL in PA test. Vit C increased thiol, SOD and CAT in the brain tissues while, reduced MDA. Results of present study confirmed the beneficial effects of Vit C on learning and memory. It also demonstrated that Vit C has protective effects on hypothyroidism-associated learning and memory impairment in juvenile rats which might be elucidated by the antioxidative effects.

  5. Motor imagery-based implicit sequence learning depends on the formation of stimulus-response associations.

    Science.gov (United States)

    Kraeutner, Sarah N; Gaughan, Theresa C; Eppler, Sarah N; Boe, Shaun G

    2017-07-01

    Implicit sequence learning (ISL) occurs without conscious awareness and is critical for skill acquisition. The extent to which ISL occurs is a function of exposure (i.e., total training time and/or sequence to noise ratio) to a repeated sequence, and thus the cognitive mechanism underlying ISL is the formation of stimulus-response associations. As the majority of ISL studies employ paradigms whereby individuals unknowingly physically practice a repeated sequence, the cognitive mechanism underlying ISL through motor imagery (MI), the mental rehearsal of movement, remains unknown. This study examined the cognitive mechanisms of MI-based ISL by probing the link between exposure and the resultant ISL. Seventy-two participants underwent MI-based practice of an ISL task following randomization to one of four conditions: 4 training blocks with a high (4-High) or low (4-Low) sequence to noise ratio, or 2 training blocks with a high (2-High) or low (2-Low) sequence to noise ratio. Reaction time differences (dRT) and effect sizes between repeated and random sequences assessed the extent of learning. All groups showed a degree of ISL, yet effect sizes indicated a greater degree of learning in groups with higher exposure (4-Low and 4-High). Findings indicate that the extent to which ISL occurs through MI is impacted by manipulations to total training time and the sequence to noise ratio. Overall, we show that the extent of ISL occurring through MI is a function of exposure, indicating that like physical practice, the cognitive mechanisms of MI-based ISL rely on the formation of stimulus response associations. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Information processing in illness representation: Implications from an associative-learning framework.

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    Lowe, Rob; Norman, Paul

    2017-03-01

    The common-sense model (Leventhal, Meyer, & Nerenz, 1980) outlines how illness representations are important for understanding adjustment to health threats. However, psychological processes giving rise to these representations are little understood. To address this, an associative-learning framework was used to model low-level process mechanics of illness representation and coping-related decision making. Associative learning was modeled within a connectionist network simulation. Two types of information were paired: Illness identities (indigestion, heart attack, cancer) were paired with illness-belief profiles (cause, timeline, consequences, control/cure), and specific illness beliefs were paired with coping procedures (family doctor, emergency services, self-treatment). To emulate past experience, the network was trained with these pairings. As an analogue of a current illness event, the trained network was exposed to partial information (illness identity or select representation beliefs) and its response recorded. The network (a) produced the appropriate representation profile (beliefs) for a given illness identity, (b) prioritized expected coping procedures, and (c) highlighted circumstances in which activated representation profiles could include self-generated or counterfactual beliefs. Encoding and activation of illness beliefs can occur spontaneously and automatically; conventional questionnaire measurement may be insensitive to these automatic representations. Furthermore, illness representations may comprise a coherent set of nonindependent beliefs (a schema) rather than a collective of independent beliefs. Incoming information may generate a "tipping point," dramatically changing the active schema as a new illness-knowledge set is invoked. Finally, automatic activation of well-learned information can lead to the erroneous interpretation of illness events, with implications for [inappropriate] coping efforts. (PsycINFO Database Record (c) 2017 APA, all

  7. Learning-enhanced coupling between ripple oscillations in association cortices and hippocampus.

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    Khodagholy, Dion; Gelinas, Jennifer N; Buzsáki, György

    2017-10-20

    Consolidation of declarative memories requires hippocampal-neocortical communication. Although experimental evidence supports the role of sharp-wave ripples in transferring hippocampal information to the neocortex, the exact cortical destinations and the physiological mechanisms of such transfer are not known. We used a conducting polymer-based conformable microelectrode array (NeuroGrid) to record local field potentials and neural spiking across the dorsal cortical surface of the rat brain, combined with silicon probe recordings in the hippocampus, to identify candidate physiological patterns. Parietal, midline, and prefrontal, but not primary cortical areas, displayed localized ripple (100 to 150 hertz) oscillations during sleep, concurrent with hippocampal ripples. Coupling between hippocampal and neocortical ripples was strengthened during sleep following learning. These findings suggest that ripple-ripple coupling supports hippocampal-association cortical transfer of memory traces. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  8. Mild maternal stress disrupts associative learning and increases aggression in offspring.

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    Eaton, L; Edmonds, E J; Henry, T B; Snellgrove, D L; Sloman, K A

    2015-05-01

    Maternal stress has been shown to affect behaviour of offspring in a wide range of animals, but this evidence has come from studies that exposed gestating mothers to acute or severe stressors, such as restraint or exposure to synthetic stress hormones. Here we show that exposure of mothers to even a mild stressor reduces associative learning and increases aggression in offspring. Female guppies were exposed to routine husbandry procedures that produced only a minimal, non-significant, elevation of the stress hormone cortisol. In contrast to controls, offspring from mothers that experienced this mild stress failed to learn to associate a colour cue and food reward, and showed a greater amount of inter-individual variation in behaviour compared with control offspring. This mild stress also resulted in offspring that were more aggressive towards their own mirror image than controls. While it is possible that these results could represent the transmission of beneficial maternal characteristics to offspring born into unpredictable environments, the potential for mild maternal stress to affect offspring performance also has important implications for research into the trans-generational effects of stress. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. Brain-like associative learning using a nanoscale non-volatile phase change synaptic device array

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    Sukru Burc Eryilmaz

    2014-07-01

    Full Text Available Recent advances in neuroscience together with nanoscale electronic device technology have resulted in huge interests in realizing brain-like computing hardwares using emerging nanoscale memory devices as synaptic elements. Although there has been experimental work that demonstrated the operation of nanoscale synaptic element at the single device level, network level studies have been limited to simulations. In this work, we demonstrate, using experiments, array level associative learning using phase change synaptic devices connected in a grid like configuration similar to the organization of the biological brain. Implementing Hebbian learning with phase change memory cells, the synaptic grid was able to store presented patterns and recall missing patterns in an associative brain-like fashion. We found that the system is robust to device variations, and large variations in cell resistance states can be accommodated by increasing the number of training epochs. We illustrated the tradeoff between variation tolerance of the network and the overall energy consumption, and found that energy consumption is decreased significantly for lower variation tolerance.

  10. Pathological gamblers are more vulnerable to the illusion of control in a standard associative learning task

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    Cristina eOrgaz

    2013-06-01

    Full Text Available An illusion of control is said to occur when a person believes that he or she controls an outcome that is uncontrollable. Pathological gambling has often been related to an illusion of control, but the assessment of the illusion has generally used introspective methods in domain-specific (i.e., gambling situations. The illusion of control of pathological gamblers, however, could be a more general problem, affecting other aspects of their daily life. Thus, we tested them using a standard associative learning task which is known to produce illusions of control in most people under certain conditions. The results showed that the illusion was significantly stronger in pathological gamblers than in a control undiagnosed sample. This suggests (a that the experimental tasks used in basic associative learning research could be used to detect illusions of control in gamblers in a more indirect way, as compared to introspective and domain-specific questionnaires; and (b, that in addition to gambling-specific problems, pathological gamblers may have a higher-than-normal illusion of control in their daily life.

  11. Automatic association of chats and video tracks for activity learning and recognition in aerial video surveillance.

    Science.gov (United States)

    Hammoud, Riad I; Sahin, Cem S; Blasch, Erik P; Rhodes, Bradley J; Wang, Tao

    2014-10-22

    We describe two advanced video analysis techniques, including video-indexed by voice annotations (VIVA) and multi-media indexing and explorer (MINER). VIVA utilizes analyst call-outs (ACOs) in the form of chat messages (voice-to-text) to associate labels with video target tracks, to designate spatial-temporal activity boundaries and to augment video tracking in challenging scenarios. Challenging scenarios include low-resolution sensors, moving targets and target trajectories obscured by natural and man-made clutter. MINER includes: (1) a fusion of graphical track and text data using probabilistic methods; (2) an activity pattern learning framework to support querying an index of activities of interest (AOIs) and targets of interest (TOIs) by movement type and geolocation; and (3) a user interface to support streaming multi-intelligence data processing. We also present an activity pattern learning framework that uses the multi-source associated data as training to index a large archive of full-motion videos (FMV). VIVA and MINER examples are demonstrated for wide aerial/overhead imagery over common data sets affording an improvement in tracking from video data alone, leading to 84% detection with modest misdetection/false alarm results due to the complexity of the scenario. The novel use of ACOs and chat Sensors 2014, 14 19844 messages in video tracking paves the way for user interaction, correction and preparation of situation awareness reports.

  12. Automatic Association of Chats and Video Tracks for Activity Learning and Recognition in Aerial Video Surveillance

    Directory of Open Access Journals (Sweden)

    Riad I. Hammoud

    2014-10-01

    Full Text Available We describe two advanced video analysis techniques, including video-indexed by voice annotations (VIVA and multi-media indexing and explorer (MINER. VIVA utilizes analyst call-outs (ACOs in the form of chat messages (voice-to-text to associate labels with video target tracks, to designate spatial-temporal activity boundaries and to augment video tracking in challenging scenarios. Challenging scenarios include low-resolution sensors, moving targets and target trajectories obscured by natural and man-made clutter. MINER includes: (1 a fusion of graphical track and text data using probabilistic methods; (2 an activity pattern learning framework to support querying an index of activities of interest (AOIs and targets of interest (TOIs by movement type and geolocation; and (3 a user interface to support streaming multi-intelligence data processing. We also present an activity pattern learning framework that uses the multi-source associated data as training to index a large archive of full-motion videos (FMV. VIVA and MINER examples are demonstrated for wide aerial/overhead imagery over common data sets affording an improvement in tracking from video data alone, leading to 84% detection with modest misdetection/false alarm results due to the complexity of the scenario. The novel use of ACOs and chat Sensors 2014, 14 19844 messages in video tracking paves the way for user interaction, correction and preparation of situation awareness reports.

  13. Predicting Protein-protein Association Rates using Coarse-grained Simulation and Machine Learning

    Science.gov (United States)

    Xie, Zhong-Ru; Chen, Jiawen; Wu, Yinghao

    2017-04-01

    Protein-protein interactions dominate all major biological processes in living cells. We have developed a new Monte Carlo-based simulation algorithm to study the kinetic process of protein association. We tested our method on a previously used large benchmark set of 49 protein complexes. The predicted rate was overestimated in the benchmark test compared to the experimental results for a group of protein complexes. We hypothesized that this resulted from molecular flexibility at the interface regions of the interacting proteins. After applying a machine learning algorithm with input variables that accounted for both the conformational flexibility and the energetic factor of binding, we successfully identified most of the protein complexes with overestimated association rates and improved our final prediction by using a cross-validation test. This method was then applied to a new independent test set and resulted in a similar prediction accuracy to that obtained using the training set. It has been thought that diffusion-limited protein association is dominated by long-range interactions. Our results provide strong evidence that the conformational flexibility also plays an important role in regulating protein association. Our studies provide new insights into the mechanism of protein association and offer a computationally efficient tool for predicting its rate.

  14. Arts and Learning Research, 1991. The Journal of the Arts and Learning Special Interest Group of the American Educational Research Association (Chicago, Illinois, April 1991).

    Science.gov (United States)

    Stuhr, Patricia L., Ed.

    1991-01-01

    The papers gathered in this volume were presented at the 1991 meeting of the American Educational Research Association. All the papers were presented as part of the Arts and Learning Special Interest Group (SIG) or were cosponsored by the arts SIG. Following an editorial, papers in this volume are: "Four Types of Women's History and How They…

  15. Equine Assisted Psychotherapy: The Equine Assisted Growth and Learning Association's Model Overview of Equine-Based Modalities

    Science.gov (United States)

    Notgrass, Clayton G.; Pettinelli, J. Douglas

    2015-01-01

    This article describes the Equine Assisted Growth and Learning Association's (EAGALA) experiential model called "Equine Assisted Psychotherapy" (EAP). EAGALA's model is based on the Association for Experiential Education's (AEE) tenets and is focused on the learner's experience with horses. Drawing on the historical use of equines in the…

  16. A genome wide association study of mathematical ability reveals an association at chromosome 3q29, a locus associated with autism and learning difficulties: a preliminary study.

    Directory of Open Access Journals (Sweden)

    Simon Baron-Cohen

    Full Text Available Mathematical ability is heritable, but few studies have directly investigated its molecular genetic basis. Here we aimed to identify specific genetic contributions to variation in mathematical ability. We carried out a genome wide association scan using pooled DNA in two groups of U.K. samples, based on end of secondary/high school national academic exam achievement: high (n = 419 versus low (n = 183 mathematical ability while controlling for their verbal ability. Significant differences in allele frequencies between these groups were searched for in 906,600 SNPs using the Affymetrix GeneChip Human Mapping version 6.0 array. After meeting a threshold of p<1.5×10(-5, 12 SNPs from the pooled association analysis were individually genotyped in 542 of the participants and analyzed to validate the initial associations (lowest p-value 1.14 ×10(-6. In this analysis, one of the SNPs (rs789859 showed significant association after Bonferroni correction, and four (rs10873824, rs4144887, rs12130910 rs2809115 were nominally significant (lowest p-value 3.278 × 10(-4. Three of the SNPs of interest are located within, or near to, known genes (FAM43A, SFT2D1, C14orf64. The SNP that showed the strongest association, rs789859, is located in a region on chromosome 3q29 that has been previously linked to learning difficulties and autism. rs789859 lies 1.3 kbp downstream of LSG1, and 700 bp upstream of FAM43A, mapping within the potential promoter/regulatory region of the latter. To our knowledge, this is only the second study to investigate the association of genetic variants with mathematical ability, and it highlights a number of interesting markers for future study.

  17. Advanced Parkinson’s disease effect on goal-directed and habitual processes involved in visuomotor associative learning

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    Fadila eHadj-Bouziane

    2013-01-01

    Full Text Available The present behavioral study readdresses the question of habit learning in Parkinson's disease. Patients were early onset, non-demented, dopa-responsive, candidates for surgical treatment, similar to those we found earlier as suffering greater dopamine depletion in the putamen than in the caudate nucleus. The task was the same conditional associative learning task as that used previously in monkeys and healthy humans to unveil the striatum involvement in habit learning. Sixteen patients and 20 age- and education-matched healthy control subjects learned sets of 3 visuo-motor associations between complex patterns and joystick displacements during two testing sessions separated by a few hours. We distinguished errors preceding versus following the first correct response to compare patients' performance during the earliest phase of learning dominated by goal-directed actions with that observed later on, when responses start to become habitual. The disease significantly retarded both learning phases, especially in patients under sixty years of age. However, only the late phase deficit was disease severity-dependent and persisted on the second testing session. These findings provide the first corroboration in Parkinson patients of two ideas well-established in the animal literature. The first is the idea that associating visual stimuli to motor acts is a form of habit learning that engages the striatum. It is confirmed here by the global impairment in visuo-motor learning induced by Parkinson's disease. The second idea is that goal-directed behaviors are predominantly caudate-dependent whereas habitual responses are primarily putamen-dependent. At the advanced Parkinson's disease stages tested here, dopamine depletion is greater in the putamen than in the caudate nucleus. Accordingly, the late phase of learning corresponding to the emergence of habitual responses was more vulnerable to the disease than the early phase dominated by goal

  18. Learning democracy in a Swedish gamers’ association: Representative democracy as experiential knowledge in a liquid civil society

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    Tobias Harding

    2011-10-01

    Full Text Available To explore the role of civil society organizations in learning democracy this articlecombines the concept of democracy as 'phronesis' with neo-institutional theory, as well as with Hannah Pitkin's concepts of representation. It presents a case study (based on qualitative research of how democracy is learned in SVEROK, a Swedish youth organization focusing on activities such as computer and role-playing games, activities often associated with informal organization. In SVEROK they are organized in an organization sharing many features with established Swedish organizations, including hierarchic formal representative democracy. The norm in SVEROK is a pragmatic organizational knowledge focusing on substantive and formal representation. Organized education plays only a limited role. Learning is typically informal and experience-based. An organization similar to earlier national organizations is createdby self-organized and self-governing associations in government-supported cooperation. The case study supports Theda Skocpol's argument that organizationalstructure is vital to democratic learning.

  19. Grapheme learning and grapheme-color synesthesia: Toward a comprehensive model of grapheme-color association

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    Michiko eAsano

    2013-11-01

    Full Text Available Recent progress in grapheme-color synesthesia research has revealed that certain regularities, as well as individual differences, figure into grapheme-color associations. Although several factors are known to regulate grapheme-color associations, the impact of factors, including their interrelationships, on synesthesia remains unclear. We investigated determinants of synesthetic color for graphemes (characters, letters of Hiragana, a phonetic script in the Japanese language, and the English alphabet. Results revealed that grapheme ordinality was the strongest predictor of synesthetic colors for Hiragana characters, followed by character sound, and visual shape. Ordinality and visual shapes also significantly predicted synesthetic colors for English alphabet letters, however, sounds did not. The relative impact of grapheme properties on grapheme-color associations and the differences between these two writing systems are accounted for by considering the way graphemes are processed in the brain and introduced during an individual's development. A new model is proposed which takes into account the developmental process of grapheme learning. The model provides comprehensive explanation of synesthetic grapheme-color association determination processes, including the differences across writing systems.

  20. Plasticity of left perisylvian white-matter tracts is associated with individual differences in math learning.

    Science.gov (United States)

    Jolles, Dietsje; Wassermann, Demian; Chokhani, Ritika; Richardson, Jennifer; Tenison, Caitlin; Bammer, Roland; Fuchs, Lynn; Supekar, Kaustubh; Menon, Vinod

    2016-04-01

    Plasticity of white matter tracts is thought to be essential for cognitive development and academic skill acquisition in children. However, a dearth of high-quality diffusion tensor imaging (DTI) data measuring longitudinal changes with learning, as well as methodological difficulties in multi-time point tract identification have limited our ability to investigate plasticity of specific white matter tracts. Here, we examine learning-related changes of white matter tracts innervating inferior parietal, prefrontal and temporal regions following an intense 2-month math tutoring program. DTI data were acquired from 18 third grade children, both before and after tutoring. A novel fiber tracking algorithm based on a White Matter Query Language (WMQL) was used to identify three sections of the superior longitudinal fasciculus (SLF) linking frontal and parietal (SLF-FP), parietal and temporal (SLF-PT) and frontal and temporal (SLF-FT) cortices, from which we created child-specific probabilistic maps. The SLF-FP, SLF-FT, and SLF-PT tracts identified with the WMQL method were highly reliable across the two time points and showed close correspondence to tracts previously described in adults. Notably, individual differences in behavioral gains after 2 months of tutoring were specifically correlated with plasticity in the left SLF-FT tract. Our results extend previous findings of individual differences in white matter integrity, and provide important new insights into white matter plasticity related to math learning in childhood. More generally, our quantitative approach will be useful for future studies examining longitudinal changes in white matter integrity associated with cognitive skill development.

  1. Calcium stable isotope geochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Gausonne, Nikolaus [Muenster Univ. (Germany). Inst. fuer Mineralogie; Schmitt, Anne-Desiree [Strasbourg Univ. (France). LHyGeS/EOST; Heuser, Alexander [Bonn Univ. (Germany). Steinmann-Inst. fuer Geologie, Mineralogie und Palaeontologie; Wombacher, Frank [Koeln Univ. (Germany). Inst. fuer Geologie und Mineralogie; Dietzel, Martin [Technische Univ. Graz (Austria). Inst. fuer Angewandte Geowissenschaften; Tipper, Edward [Cambridge Univ. (United Kingdom). Dept. of Earth Sciences; Schiller, Martin [Copenhagen Univ. (Denmark). Natural History Museum of Denmark

    2016-08-01

    This book provides an overview of the fundamentals and reference values for Ca stable isotope research, as well as current analytical methodologies including detailed instructions for sample preparation and isotope analysis. As such, it introduces readers to the different fields of application, including low-temperature mineral precipitation and biomineralisation, Earth surface processes and global cycling, high-temperature processes and cosmochemistry, and lastly human studies and biomedical applications. The current state of the art in these major areas is discussed, and open questions and possible future directions are identified. In terms of its depth and coverage, the current work extends and complements the previous reviews of Ca stable isotope geochemistry, addressing the needs of graduate students and advanced researchers who want to familiarize themselves with Ca stable isotope research.

  2. The relationship between visitor characteristics and learning-associated behaviors in a science museum discovery space

    Science.gov (United States)

    Lozowski Boisvert, Dorothy; Jochums Slez, Brenda

    As informal educational institutions, science museums must do more than entertain and amaze visitors. Museum educators must design exhibits that attract and hold the attention of visitors long enough so that the visitors become engaged with the exhibits and learn from them. In order for museum educators to develop such exhibits, more information is needed about the variables associated with learning in museums. This study contributes to the growing body of knowledge on informal education by examining the relationship between visitor characteristics and attraction, holding power, and visitor engagement.One hundred fifty-four visitors to a science museum discovery space were observed as they interacted freely with the exhibits. Trained volunteers recorded the subjects' movements including the exhibits at which they stopped (attraction), the amount of time spent at each exhibit (holding power), and behaviors indicative of subjects' engagement levels with the exhibits. Data indicated significant differences between age group and the holding power of exhibits. Though not significant statistically, a similar trend was noted between age group and attraction and visitor engagement level. No significant differences were found between gender or social grouping and attraction, holding power, or engagement levels.

  3. Associative learning versus fear habituation as predictors of long-term extinction retention.

    Science.gov (United States)

    Brown, Lily A; LeBeau, Richard T; Chat, Ka Yi; Craske, Michelle G

    2017-06-01

    Violation of unconditioned stimulus (US) expectancy during extinction training may enhance associative learning and result in improved long-term extinction retention compared to within-session habituation. This experiment examines variation in US expectancy (i.e., expectancy violation) as a predictor of long-term extinction retention. It also examines within-session habituation of fear-potentiated startle (electromyography, EMG) and fear of conditioned stimuli (CS) throughout extinction training as predictors of extinction retention. Participants (n = 63) underwent fear conditioning, extinction and retention and provided continuous ratings of US expectancy and EMG, as well as CS fear ratings before and after each phase. Variation in US expectancy throughout extinction and habituation of EMG and fear was entered into a regression as predictors of retention and reinstatement of levels of expectancy and fear. Greater variation in US expectancy throughout extinction training was significantly predictive of enhanced extinction performance measured at retention test, although not after reinstatement test. Slope of EMG and CS fear during extinction did not predict retention of extinction. Within-session habituation of EMG and self-reported fear is not sufficient for long-term retention of extinction learning, and models emphasizing expectation violation may result in enhanced outcomes.

  4. Stable Fly, (L., Dispersal and Governing Factors

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    Allan T. Showler

    2015-01-01

    Full Text Available Although the movement of stable fly, Stomoxys calcitrans (L., has been studied, its extent and significance has been uncertain. On a local scale (13 km is mainly wind-driven by weather fronts that carry stable flies from inland farm areas for up to 225 km to beaches of northwestern Florida and Lake Superior. Stable flies can reproduce for a short time each year in washed-up sea grass, but the beaches are not conducive to establishment. Such movement is passive and does not appear to be advantageous to stable fly's survival. On a regional scale, stable flies exhibit little genetic differentiation, and on the global scale, while there might be more than one “lineage”, the species is nevertheless considered to be panmictic. Population expansion across much of the globe likely occurred from the late Pleistocene to the early Holocene in association with the spread of domesticated nomad livestock and particularly with more sedentary, penned livestock.

  5. Retrieval cues that trigger reconsolidation of associative fear memory are not necessarily an exact replica of the original learning experience.

    Science.gov (United States)

    Soeter, Marieke; Kindt, Merel

    2015-01-01

    Disrupting the process of memory reconsolidation may point to a novel therapeutic strategy for the permanent reduction of fear in patients suffering from anxiety disorders. However both in animal and human studies the retrieval cue typically involves a re-exposure to the original fear-conditioned stimulus (CS). A relevant question is whether abstract cues not directly associated with the threat event also trigger reconsolidation, given that anxiety disorders often result from vicarious or unobtrusive learning for which no explicit memory exists. Insofar as the fear memory involves a flexible representation of the original learning experience, we hypothesized that the process of memory reconsolidation may also be triggered by abstract cues. We addressed this hypothesis by using a differential human fear-conditioning procedure in two distinct fear-learning groups. We predicted that if fear learning involves discrimination on basis of perceptual cues within one semantic category (i.e., the perceptual-learning group, n = 15), the subsequent ambiguity of the abstract retrieval cue would not trigger memory reconsolidation. In contrast, if fear learning involves discriminating between two semantic categories (i.e., categorical-learning group, n = 15), an abstract retrieval cue would unequivocally reactivate the fear memory and might subsequently trigger memory reconsolidation. Here we show that memory reconsolidation may indeed be triggered by another cue than the one that was present during the original learning occasion, but this effect depends on the learning history. Evidence for fear memory reconsolidation was inferred from the fear-erasing effect of one pill of propranolol (40 mg) systemically administered upon exposure to the abstract retrieval cue. Our finding that reconsolidation of a specific fear association does not require exposure to the original retrieval cue supports the feasibility of reconsolidation-based interventions for emotional disorders.

  6. Retrieval cues that trigger reconsolidation of associative fear memory are not necessarily an exact replica of the original learning experience

    Directory of Open Access Journals (Sweden)

    Marieke eSoeter

    2015-05-01

    Full Text Available Disrupting the process of memory reconsolidation may point to a novel therapeutic strategy for the permanent reduction of fear in patients suffering from anxiety disorders. However both in animal and human studies the retrieval cue typically involves a re-exposure to the original fear-conditioned stimulus. A relevant question is whether abstract cues not directly associated with the threat event also trigger reconsolidation, given that anxiety disorders often result from vicarious or unobtrusive learning for which no explicit memory exists. Insofar as the fear memory involves a flexible representation of the original learning experience, we hypothesized that the process of memory reconsolidation may also be triggered by abstract cues. We addressed this hypothesis by using a differential human fear-conditioning procedure in two distinct fear-learning groups. We predicted that if fear learning involves discrimination on basis of perceptual cues within one semantic category (i.e., the perceptual-learning group, n = 15, the subsequent ambiguity of the abstract retrieval cue would not trigger memory reconsolidation. In contrast, if fear learning involves discriminating between two semantic categories (i.e., categorical-learning group, n = 15, an abstract retrieval cue would unequivocally reactivate the fear memory and might subsequently trigger memory reconsolidation. Here we show that memory reconsolidation may indeed be triggered by another cue than the one that was present during the original learning occasion, but this effect depends on the learning history. Evidence for fear memory reconsolidation was inferred from the fear-erasing effect of one pill of propranolol (40 mg systemically administered upon exposure to the abstract retrieval cue. Our finding that reconsolidation of a specific fear association does not require exposure to the original retrieval cue supports the feasibility of reconsolidation-based interventions for emotional disorders.

  7. Associations between polygenic risk for schizophrenia and brain function during probabilistic learning in healthy individuals.

    Science.gov (United States)

    Lancaster, Thomas M; Ihssen, Niklas; Brindley, Lisa M; Tansey, Katherine E; Mantripragada, Kiran; O'Donovan, Michael C; Owen, Michael J; Linden, David E J

    2016-02-01

    A substantial proportion of schizophrenia liability can be explained by additive genetic factors. Risk profile scores (RPS) directly index risk using a summated total of common risk variants weighted by their effect. Previous studies suggest that schizophrenia RPS predict alterations to neural networks that support working memory and verbal fluency. In this study, we apply schizophrenia RPS to fMRI data to elucidate the effects of polygenic risk on functional brain networks during a probabilistic-learning neuroimaging paradigm. The neural networks recruited during this paradigm have previously been shown to be altered to unmedicated schizophrenia patients and relatives of schizophrenia patients, which may reflect genetic susceptibility. We created schizophrenia RPS using summary data from the Psychiatric Genetic Consortium (Schizophrenia Working Group) for 83 healthy individuals and explore associations between schizophrenia RPS and blood oxygen level dependency (BOLD) during periods of choice behavior (switch-stay) and reflection upon choice outcome (reward-punishment). We show that schizophrenia RPS is associated with alterations in the frontal pole (PWHOLE-BRAIN-CORRECTED  = 0.048) and the ventral striatum (PROI-CORRECTED  = 0.036), during choice behavior, but not choice outcome. We suggest that the common risk variants that increase susceptibility to schizophrenia can be associated with alterations in the neural circuitry that support the processing of changing reward contingencies. Hum Brain Mapp 37:491-500, 2016. © 2015 Wiley Periodicals, Inc. © 2015 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc.

  8. Associative learning in humans--conditioning of sensory-evoked brain activity.

    Science.gov (United States)

    Skrandies, W; Jedynak, A

    2000-01-01

    A classical conditioning paradigm was employed in two experiments performed on 35 human volunteers. In nine subjects, the presentation of Landolt rings (conditioned stimuli, CS + ) was paired with an electric stimulus (unconditioned stimuli, UCS) applied to the left median nerve. Neutral visual control stimuli were full circles (CS -) that were not paired with the UCS. The skin conductance response (SCR) was determined in a time interval of 5 s after onset of the visual stimuli, and it was measured in the acquisition and test phase. Associative learning was reflected by a SCR occurring selectively with CS +. The same experiment was repeated with another group of 26 adults while electroencephalogram (EEG) was recorded from 30 electrodes. For each subject, mean evoked potentials were computed. In 13 of the subjects, a conditioning paradigm was followed while the other subjects served as the control group (non-contingent stimulation). There were somatosensory and visual brain activity evoked by the stimuli. Conditioned components were identified by computing cross-correlation between evoked somatosensory components and the averaged EEG. In the visual evoked brain activity, three components with mean latencies of 105.4, 183.2, and 360.3 ms were analyzed. Somatosensory stimuli were followed by major components that occurred at mean latencies of 48.8, 132.5, 219.7, 294.8, and 374.2 ms latency after the shock. All components were analyzed in terms of latency, field strength, and topographic characteristics, and were compared between groups and experimental conditions. Both visual and somatosensory brain activity was significantly affected by classical conditioning. Our data illustrate how associative learning affects the topography of brain electrical activity elicited by presentation of conditioned visual stimuli.

  9. Baseline transition sleep and associated sleep episodes are related to the learning ability of rats.

    Science.gov (United States)

    Vescia, S; Mandile, P; Montagnese, P; Romano, F; Cataldo, G; Cotugno, M; Giuditta, A

    1996-12-01

    The EEGs of 18 adult male Wistar rats were recorded during a baseline session lasting 7 h (day 1). The following day, rats were trained for a 2-way active avoidance task in an automated shuttle-box. A retention test was scheduled on the third day. On the basis of the number of avoidances scored during the training and retention sessions, rats were assigned to a fast-learning group (FL; achieving criterion during the training session), a slow-learning group (SL; achieving criterion in the retention test session), and a nonlearning group (NL; failing to achieve criterion). Vigilance states were determined by analyzing EEG data in 5-s epochs and calculating EEG power spectra of consecutive time intervals as short as 1 s. This high-resolution method led to the identification of transition sleep episodes that followed slow-wave sleep (SS) and were followed by waking (TS-->W) or by paradoxical sleep (TS-->PS). Comparison of the baseline sleep variables of the 3 behavioral groups revealed the presence of several significant differences. These observations were confirmed by the results of correlative analyses between baseline sleep variables and number of avoidances scored during the training and retention sessions. The most reliable indices of the capacity to learn the avoidance task were the amounts of SS preceding the TS-->W or the TS-->PS sequence, and the amounts of either component of the latter sequence. These variables displayed markedly higher values in FL rats. In addition, the amount of SS preceding TS-->W and the amount of TS-->(W) were significantly correlated with the number of avoidances scored during the training session. On the other hand, 1' SS-->(PS) and (SS)-->PS episodes were longer in NL rats than in SL or FL rats, respectively; and 2, the duration of SS-->(PS) episodes was inversely correlated with the number of avoidances of the first training period. The data are interpreted to suggest that TS and associated sleep episodes may predict the

  10. Evolutionary Stable Strategy

    Indian Academy of Sciences (India)

    2016-08-26

    Aug 26, 2016 ... Home; Journals; Resonance – Journal of Science Education; Volume 21; Issue 9. Evolutionary Stable Strategy: Application of Nash Equilibrium in Biology. General ... Using some examples of classical games, we show how evolutionary game theory can help understand behavioural decisions of animals.

  11. The Stable Concordance Genus

    OpenAIRE

    Kearney, M. Kate

    2013-01-01

    The concordance genus of a knot is the least genus of any knot in its concordance class. Although difficult to compute, it is a useful invariant that highlights the distinction between the three-genus and four-genus. In this paper we define and discuss the stable concordance genus of a knot, which describes the behavior of the concordance genus under connected sum.

  12. Manifolds admitting stable forms

    Czech Academy of Sciences Publication Activity Database

    Le, Hong-Van; Panák, Martin; Vanžura, Jiří

    2008-01-01

    Roč. 49, č. 1 (2008), s. 101-11 ISSN 0010-2628 R&D Projects: GA ČR(CZ) GP201/05/P088 Institutional research plan: CEZ:AV0Z10190503 Keywords : stable forms * automorphism groups Subject RIV: BA - General Mathematics

  13. Stable isotope studies

    International Nuclear Information System (INIS)

    Ishida, T.

    1992-01-01

    The research has been in four general areas: (1) correlation of isotope effects with molecular forces and molecular structures, (2) correlation of zero-point energy and its isotope effects with molecular structure and molecular forces, (3) vapor pressure isotope effects, and (4) fractionation of stable isotopes. 73 refs, 38 figs, 29 tabs

  14. Interactive Stable Ray Tracing

    DEFF Research Database (Denmark)

    Dal Corso, Alessandro; Salvi, Marco; Kolb, Craig

    2017-01-01

    Interactive ray tracing applications running on commodity hardware can suffer from objectionable temporal artifacts due to a low sample count. We introduce stable ray tracing, a technique that improves temporal stability without the over-blurring and ghosting artifacts typical of temporal post-pr...

  15. Association of learning styles with research self-efficacy: study of short-term research training program for medical students.

    Science.gov (United States)

    Dumbauld, Jill; Black, Michelle; Depp, Colin A; Daly, Rebecca; Curran, Maureen A; Winegarden, Babbi; Jeste, Dilip V

    2014-12-01

    With a growing need for developing future physician scientists, identifying characteristics of medical students who are likely to benefit from research training programs is important. This study assessed if specific learning styles of medical students, participating in federally funded short-term research training programs, were associated with research self-efficacy, a potential predictor of research career success. Seventy-five first-year medical students from 28 medical schools, selected to participate in two competitive NIH-supported summer programs for research training in aging, completed rating scales to evaluate learning styles at baseline, and research self-efficacy before and after training. We examined associations of individual learning styles (visual-verbal, sequential-global, sensing-intuitive, and active-reflective) with students' gender, ranking of medical school, and research self-efficacy. Research self-efficacy improved significantly following the training programs. Students with a verbal learning style reported significantly greater research self-efficacy at baseline, while visual, sequential, and intuitive learners demonstrated significantly greater increases in research self-efficacy from baseline to posttraining. No significant relationships were found between learning styles and students' gender or ranking of their medical school. Assessments of learning styles may provide useful information to guide future training endeavors aimed at developing the next generation of physician-scientists. © 2014 Wiley Periodicals, Inc.

  16. Stable long-term chronic brain mapping at the single-neuron level.

    Science.gov (United States)

    Fu, Tian-Ming; Hong, Guosong; Zhou, Tao; Schuhmann, Thomas G; Viveros, Robert D; Lieber, Charles M

    2016-10-01

    Stable in vivo mapping and modulation of the same neurons and brain circuits over extended periods is critical to both neuroscience and medicine. Current electrical implants offer single-neuron spatiotemporal resolution but are limited by such factors as relative shear motion and chronic immune responses during long-term recording. To overcome these limitations, we developed a chronic in vivo recording and stimulation platform based on flexible mesh electronics, and we demonstrated stable multiplexed local field potentials and single-unit recordings in mouse brains for at least 8 months without probe repositioning. Properties of acquired signals suggest robust tracking of the same neurons over this period. This recording and stimulation platform allowed us to evoke stable single-neuron responses to chronic electrical stimulation and to carry out longitudinal studies of brain aging in freely behaving mice. Such advantages could open up future studies in mapping and modulating changes associated with learning, aging and neurodegenerative diseases.

  17. Associative learning in two closely related parasitoid wasps: a neuroecological approach

    NARCIS (Netherlands)

    Bleeker, M.A.K.

    2005-01-01

    Insects are useful model organisms to study learning and memory. Their brains are less complex than vertebrate brains, but the basic mechanisms of learning and memory are similar in both taxa. In this thesis I study learning and subsequent memory formation in two parasitoid wasp species that differ

  18. Online Learning Behaviors for Radiology Interns Based on Association Rules and Clustering Technique

    Science.gov (United States)

    Chen, Hsing-Shun; Liou, Chuen-He

    2014-01-01

    In a hospital, clinical teachers must also care for patients, so there is less time for the teaching of clinical courses, or for discussing clinical cases with interns. However, electronic learning (e-learning) can complement clinical skills education for interns in a blended-learning process. Students discuss and interact with classmates in an…

  19. The association between motivation, affect, and self-regulated learning when solving problems

    NARCIS (Netherlands)

    M.A. Baars (Martine); L. Wijnia (Lisette); G.W.C. Paas (Fred)

    2017-01-01

    textabstractSelf-regulated learning (SRL) skills are essential for learning during school years, particularly in complex problem-solving domains, such as biology and math. Although a lot of studies have focused on the cognitive resources that are needed for learning to solve problems in a

  20. Associations between Chinese EFL Graduate Students' Beliefs and Language Learning Strategies

    Science.gov (United States)

    Tang, Mailing; Tian, Jianrong

    2015-01-01

    This study, using Horwitz's Beliefs about Language Learning Inventory and Oxford's Strategy Inventory for Language Learning, investigated learners' beliefs about language learning and their choice of strategy categories among 546 graduate students in China. The correlation between learners' beliefs and their strategy categories use was examined.…

  1. Improved children's motor learning of the basketball free shooting pattern by associating subjective error estimation and extrinsic feedback.

    Science.gov (United States)

    Silva, Leandro de Carvalho da; Pereira-Monfredini, Carla Ferro; Teixeira, Luis Augusto

    2017-09-01

    This study aimed at assessing the interaction between subjective error estimation and frequency of extrinsic feedback in the learning of the basketball free shooting pattern by children. 10- to 12-year olds were assigned to 1 of 4 groups combining subjective error estimation and relative frequency of extrinsic feedback (33% × 100%). Analysis of performance was based on quality of movement pattern. Analysis showed superior learning of the group combining error estimation and 100% feedback frequency, both groups receiving feedback on 33% of trials achieved intermediate results, and the group combining no requirement of error estimation and 100% feedback frequency had the poorest learning. Our results show the benefit of subjective error estimation in association with high frequency of extrinsic feedback in children's motor learning of a sport motor pattern.

  2. The risk of stable partnerships: associations between partnership characteristics and unprotected anal intercourse among men who have sex with men and transgender women recently diagnosed with HIV and/or STI in Lima, Peru.

    Directory of Open Access Journals (Sweden)

    Mary C Cambou

    Full Text Available Partnership type is an important factor associated with unprotected anal intercourse (UAI and subsequent risk for HIV and sexually transmitted infections (STI. We examined the association of partnership type with UAI among men who have sex with men (MSM and male-to-female transgender women (TGW in Lima, Peru, recently diagnosed with HIV and/or STI.We report data from a cross-sectional analysis of MSM and TGW recently diagnosed with HIV and/or STI in Lima, Peru between 2011 and 2012. We surveyed participants regarding UAI with up to their three most recent sexual partners according to partner type. Multivariable Generalized Estimate Equating (GEE models with Poisson distribution were used to estimate prevalence ratios (PR for UAI according to partner type.Among 339 MSM and TGW recently diagnosed with HIV and/or STI (mean age: 30.6 years, SD 9.0, 65.5% self-identified as homosexual/gay, 16.0% as bisexual, 15.2% as male-to-female transgender, and 3.3% as heterosexual. Participants provided information on 893 recent male or TGW partners with whom they had engaged in insertive or receptive anal intercourse: 28.9% stable partners, 56.4% non-stable/non-transactional partners (i.e. casual or anonymous, and 14.7% transactional partners (i.e. transactional sex client or sex worker. Unprotected anal intercourse was reported with 41.3% of all partners. In multivariable analysis, factors associated with UAI included partnership type (non-stable/non-transactional partner APR 0.73, [95% CI 0.59-0.91], transactional partner APR 0.53 [0.36-0.78], p10 encounters APR 1.43 [1.06-1.92], p10 sexual encounters, suggesting UAI is more prevalent in partnerships with a greater degree of interpersonal commitment. Further research assessing partner-level factors and behavior is critical for improving HIV and/or STI prevention efforts among Peruvian MSM and TGW.

  3. The risk of stable partnerships: associations between partnership characteristics and unprotected anal intercourse among men who have sex with men and transgender women recently diagnosed with HIV and/or STI in Lima, Peru.

    Science.gov (United States)

    Cambou, Mary C; Perez-Brumer, Amaya G; Segura, Eddy R; Salvatierra, H Javier; Lama, Javier R; Sanchez, Jorge; Clark, Jesse L

    2014-01-01

    Partnership type is an important factor associated with unprotected anal intercourse (UAI) and subsequent risk for HIV and sexually transmitted infections (STI). We examined the association of partnership type with UAI among men who have sex with men (MSM) and male-to-female transgender women (TGW) in Lima, Peru, recently diagnosed with HIV and/or STI. We report data from a cross-sectional analysis of MSM and TGW recently diagnosed with HIV and/or STI in Lima, Peru between 2011 and 2012. We surveyed participants regarding UAI with up to their three most recent sexual partners according to partner type. Multivariable Generalized Estimate Equating (GEE) models with Poisson distribution were used to estimate prevalence ratios (PR) for UAI according to partner type. Among 339 MSM and TGW recently diagnosed with HIV and/or STI (mean age: 30.6 years, SD 9.0), 65.5% self-identified as homosexual/gay, 16.0% as bisexual, 15.2% as male-to-female transgender, and 3.3% as heterosexual. Participants provided information on 893 recent male or TGW partners with whom they had engaged in insertive or receptive anal intercourse: 28.9% stable partners, 56.4% non-stable/non-transactional partners (i.e. casual or anonymous), and 14.7% transactional partners (i.e. transactional sex client or sex worker). Unprotected anal intercourse was reported with 41.3% of all partners. In multivariable analysis, factors associated with UAI included partnership type (non-stable/non-transactional partner APR 0.73, [95% CI 0.59-0.91], transactional partner APR 0.53 [0.36-0.78], p10 encounters APR 1.43 [1.06-1.92], p10 sexual encounters, suggesting UAI is more prevalent in partnerships with a greater degree of interpersonal commitment. Further research assessing partner-level factors and behavior is critical for improving HIV and/or STI prevention efforts among Peruvian MSM and TGW.

  4. Multiple target tracking by learning-based hierarchical association of detection responses.

    Science.gov (United States)

    Huang, Chang; Li, Yuan; Nevatia, Ramakant

    2013-04-01

    We propose a hierarchical association approach to multiple target tracking from a single camera by progressively linking detection responses into longer track fragments (i.e., tracklets). Given frame-by-frame detection results, a conservative dual-threshold method that only links very similar detection responses between consecutive frames is adopted to generate initial tracklets with minimum identity switches. Further association of these highly fragmented tracklets at each level of the hierarchy is formulated as a Maximum A Posteriori (MAP) problem that considers initialization, termination, and transition of tracklets as well as the possibility of them being false alarms, which can be efficiently computed by the Hungarian algorithm. The tracklet affinity model, which measures the likelihood of two tracklets belonging to the same target, is a linear combination of automatically learned weak nonparametric models upon various features, which is distinct from most of previous work that relies on heuristic selection of parametric models and manual tuning of their parameters. For this purpose, we develop a novel bag ranking method and train the crucial tracklet affinity models by the boosting algorithm. This bag ranking method utilizes the soft max function to relax the oversufficient objective function used by the conventional instance ranking method. It provides a tighter upper bound of empirical errors in distinguishing correct associations from the incorrect ones, and thus yields more accurate tracklet affinity models for the tracklet association problem. We apply this approach to the challenging multiple pedestrian tracking task. Systematic experiments conducted on two real-life datasets show that the proposed approach outperforms previous state-of-the-art algorithms in terms of tracking accuracy, in particular, considerably reducing fragmentations and identity switches.

  5. The Association Between Learning Climate and Adverse Obstetrical Outcomes in 16 Nontertiary Obstetrics-Gynecology Departments in the Netherlands.

    Science.gov (United States)

    Smirnova, Alina; Ravelli, Anita C J; Stalmeijer, Renée E; Arah, Onyebuchi A; Heineman, Maas Jan; van der Vleuten, Cees P M; van der Post, Joris A M; Lombarts, Kiki M J M H

    2017-12-01

    To investigate the association between learning climate and adverse perinatal and maternal outcomes in obstetrics-gynecology departments. The authors analyzed 23,629 births and 103 learning climate evaluations from 16 nontertiary obstetrics-gynecology departments in the Netherlands in 2013. Multilevel logistic regressions were used to calculate the odds of adverse perinatal and maternal outcomes, by learning climate score tertile, adjusting for maternal and department characteristics. Adverse perinatal outcomes included fetal or early neonatal mortality, five-minute Apgar score < 7, or neonatal intensive care unit admission for ≥ 24 hours. Adverse maternal outcomes included postpartum hemorrhage and/or transfusion, death, uterine rupture, or third- or fourth-degree perineal laceration. Bias analyses were conducted to quantify the sensitivity of the results to uncontrolled confounding and selection bias. Learning climate scores were significantly associated with increased odds of adverse perinatal outcomes (aOR 2.06, 95% CI 1.14-3.72). Compared with the lowest tertile, departments in the middle tertile had 46% greater odds of adverse perinatal outcomes (aOR 1.46, 95% CI 1.09-1.94); departments in the highest tertile had 69% greater odds (aOR 1.69, 95% CI 1.24-2.30). Learning climate was not associated with adverse maternal outcomes (middle vs. lowest tertile: OR 1.04, 95% CI 0.93-1.16; highest vs. lowest tertile: OR 0.98, 95% CI 0.88-1.10). Learning climate was associated with significantly increased odds of adverse perinatal, but not maternal, outcomes. Research in similar clinical contexts is needed to replicate these findings and explore potential mechanisms behind these associations.

  6. Efficient delivery of Cre-recombinase to neurons in vivo and stable transduction of neurons using adeno-associated and lentiviral vectors

    Directory of Open Access Journals (Sweden)

    Sablitzky Fred

    2004-01-01

    Full Text Available Abstract Background Inactivating genes in vivo is an important technique for establishing their function in the adult nervous system. Unfortunately, conventional knockout mice may suffer from several limitations including embryonic or perinatal lethality and the compensatory regulation of other genes. One approach to producing conditional activation or inactivation of genes involves the use of Cre recombinase to remove loxP-flanked segments of DNA. We have studied the effects of delivering Cre to the hippocampus and neocortex of adult mice by injecting replication-deficient adeno-associated virus (AAV and lentiviral (LV vectors into discrete regions of the forebrain. Results Recombinant AAV-Cre, AAV-GFP (green fluorescent protein and LV-Cre-EGFP (enhanced GFP were made with the transgene controlled by the cytomegalovirus promoter. Infecting 293T cells in vitro with AAV-Cre and LV-Cre-EGFP resulted in transduction of most cells as shown by GFP fluorescence and Cre immunoreactivity. Injections of submicrolitre quantities of LV-Cre-EGFP and mixtures of AAV-Cre with AAV-GFP into the neocortex and hippocampus of adult Rosa26 reporter mice resulted in strong Cre and GFP expression in the dentate gyrus and moderate to strong labelling in specific regions of the hippocampus and in the neocortex, mainly in neurons. The pattern of expression of Cre and GFP obtained with AAV and LV vectors was very similar. X-gal staining showed that Cre-mediated recombination had occurred in neurons in the same regions of the brain, starting at 3 days post-injection. No obvious toxic effects of Cre expression were detected even after four weeks post-injection. Conclusion AAV and LV vectors are capable of delivering Cre to neurons in discrete regions of the adult mouse brain and producing recombination.

  7. International Association for Cognitive Education and Psychology. European Regional Conference: Cognitive Development and Learning from Kindergarten to University. Program and Abstracts

    OpenAIRE

    Hessels, Marco G.P.

    2012-01-01

    Abstracts and program of the 2012 European Regional Conference "Cognitive development and learning from kindergarten to university" of the International Association for Cognitive Education and Psychology.

  8. Differential-associative processing or example elaboration: Which strategy is best for learning the definitions of related and unrelated concepts?

    Science.gov (United States)

    Hannon, Brenda

    2012-10-01

    Definitions of related concepts (e.g., genotype - phenotype ) are prevalent in introductory classes. Consequently, it is important that educators and students know which strategy(s) work best for learning them. This study showed that a new comparative elaboration strategy, called differential-associative processing, was better for learning definitions of related concepts than was an integrative elaborative strategy, called example elaboration. This outcome occurred even though example elaboration was administered in a naturalistic way (Experiment 1) and students spent more time in the example elaboration condition learning (Experiments 1, 2, 3), and generating pieces of information about the concepts (Experiments 2 and 3). Further, with unrelated concepts ( morpheme-fluid intelligence ), performance was similar regardless if students used differential-associative processing or example elaboration (Experiment 3). Taken as a whole, these results suggest that differential-associative processing is better than example elaboration for learning definitions of related concepts and is as good as example elaboration for learning definitions of unrelated concepts.

  9. tDCS Over the Motor Cortex Shows Differential Effects on Action and Object Words in Associative Word Learning in Healthy Aging

    Directory of Open Access Journals (Sweden)

    Meret Branscheidt

    2017-05-01

    Full Text Available Healthy aging is accompanied by a continuous decline in cognitive functions. For example, the ability to learn languages decreases with age, while the neurobiological underpinnings for the decline in learning abilities are not known exactly. Transcranial direct current stimulation (tDCS, in combination with appropriate experimental paradigms, is a well-established technique to investigate the mechanisms of learning. Based on previous results in young adults, we tested the suitability of an associative learning paradigm for the acquisition of action- and object-related words in a cohort of older participants. We applied tDCS to the motor cortex (MC and hypothesized an involvement of the MC in learning action-related words. To test this, a cohort of 18 healthy, older participants (mean age 71 engaged in a computer-assisted associative word-learning paradigm, while tDCS stimulation (anodal, cathodal, sham was applied to the left MC. Participants’ task performance was quantified in a randomized, cross-over experimental design. Participants successfully learned novel words, correctly translating 39.22% of the words after 1 h of training under sham stimulation. Task performance correlated with scores for declarative verbal learning and logical reasoning. Overall, tDCS did not influence associative word learning, but a specific influence was observed of cathodal tDCS on learning of action-related words during the NMDA-dependent stimulation period. Successful learning of a novel lexicon with associative learning in older participants can only be achieved when the learning procedure is changed in several aspects, relative to young subjects. Learning success showed large inter-individual variance which was dependent on non-linguistic as well as linguistic cognitive functions. Intriguingly, cathodal tDCS influenced the acquisition of action-related words in the NMDA-dependent stimulation period. However, the effect was not specific for the associative

  10. Lateralization of Sucrose Responsiveness and Non-associative Learning in Honeybees

    Directory of Open Access Journals (Sweden)

    David Baracchi

    2018-03-01

    Full Text Available Lateralization is a fundamental property of the human brain that affects perceptual, motor, and cognitive processes. It is now acknowledged that left–right laterality is widespread across vertebrates and even some invertebrates such as fruit flies and bees. Honeybees, which learn to associate an odorant (the conditioned stimulus, CS with sucrose solution (the unconditioned stimulus, US, recall this association better when trained using their right antenna than they do when using their left antenna. Correspondingly, olfactory sensilla are more abundant on the right antenna and odor encoding by projection neurons of the right antennal lobe results in better odor differentiation than those of the left one. Thus, lateralization arises from asymmetries both in the peripheral and central olfactory system, responsible for detecting the CS. Here, we focused on the US component and studied if lateralization exists in the gustatory system of Apis mellifera. We investigated whether sucrose sensitivity is lateralized both at the level of the antennae and the fore-tarsi in two independent groups of bees. Sucrose sensitivity was assessed by presenting bees with a series of increasing concentrations of sucrose solution delivered either to the left or the right antenna/tarsus and measuring the proboscis extension response to these stimuli. Bees experienced two series of stimulations, one on the left and the other on the right antenna/tarsus. We found that tarsal responsiveness was similar on both sides and that the order of testing affects sucrose responsiveness. On the contrary, antennal responsiveness to sucrose was higher on the right than on the left side, and this effect was independent of the order of antennal stimulation. Given this asymmetry, we also investigated antennal lateralization of habituation to sucrose. We found that the right antenna was more resistant to habituation, which is consistent with its higher sucrose sensitivity. Our results

  11. Functional Specialization within the Striatum along Both the Dorsal/Ventral and Anterior/Posterior Axes during Associative Learning via Reward and Punishment

    Science.gov (United States)

    Mattfeld, Aaron T.; Gluck, Mark A.; Stark, Craig E. L.

    2011-01-01

    The goal of the present study was to elucidate the role of the human striatum in learning via reward and punishment during an associative learning task. Previous studies have identified the striatum as a critical component in the neural circuitry of reward-related learning. It remains unclear, however, under what task conditions, and to what…

  12. The associations between severity of early postoperative pain, chronic postsurgical pain and plasma concentration of stable nitric oxide products after breast surgery.

    LENUS (Irish Health Repository)

    Iohom, Gabriella

    2012-02-03

    In this study, we compared the effects of two analgesic regimens on perioperative nitric oxide index (NOx) and the likelihood of subsequent development of chronic postsurgical pain (CPSP) after breast surgery and sought to determine the association among early postoperative pain, NOx, and the likelihood of subsequent development of CPSP. Twenty-nine consecutive ASA I or II patients undergoing breast surgery with axillary clearance were randomly allocated to one of two groups. Patients in group S (n = 15) received a standard intraoperative and postoperative analgesic regimen (morphine sulfate, diclofenac, dextropropoxyphene hydrochloride + acetaminophen prn). Patients in group N (n = 14) received a continuous paravertebral block (for 48 h) and acetaminophen and parecoxib (followed by celecoxib up to 5 days). Visual analog scale pain scores at rest and on arm movement were recorded regularly until the fifth postoperative day. A telephone interview was conducted 10 wk postoperatively. The McGill Pain Questionnaire was used to characterize pain. NOx was estimated preoperatively, at the end of surgery, 30 min and 2, 4, 12, 24, 48 h postoperatively. Twelve (80%) patients in group S and no patient in group N developed CPSP (P = 0.009). Compared with patients with a pain rating index > or =1 (n = 18) 10 wk postoperatively, patients with a pain rating index = 0 (n = 11) had lesser visual analog scale pain scores on movement at each postoperative time point from 30 min until 96 h postoperatively (P < 0.005) and at rest 30 min (0.6 +\\/- 1.5 versus 30.2 +\\/- 26.8; P = 0.004), 4 h (2.3 +\\/- 7.5 versus 19.0 +\\/- 25.8; P = 0.013), 8 h (4.4 +\\/- 10.2 versus 21.4 +\\/- 27.0; P = 0.03) and 12 h (0.7 +\\/- 1.2 versus 15.4 +\\/- 27.0; P = 0.035) postoperatively. NOx values were greater in group N compared with group S 48 h postoperatively (40.6 +\\/- 20.1 versus 26.4 +\\/- 13.5; P = 0.04).

  13. Stable isotope analysis

    International Nuclear Information System (INIS)

    Tibari, Elghali; Taous, Fouad; Marah, Hamid

    2014-01-01

    This report presents results related to stable isotopes analysis carried out at the CNESTEN DASTE in Rabat (Morocco), on behalf of Senegal. These analyzes cover 127 samples. These results demonstrate that Oxygen-18 and Deuterium in water analysis were performed by infrared Laser spectroscopy using a LGR / DLT-100 with Autosampler. Also, the results are expressed in δ values (‰) relative to V-SMOW to ± 0.3 ‰ for oxygen-18 and ± 1 ‰ for deuterium.

  14. Neurobehavioral factors associated with referral for learning problems in a community sample: evidence for an adaptational model for learning disorders.

    Science.gov (United States)

    Waber, Deborah P; Weiler, Michael D; Forbes, Peter W; Bernstein, Jane H; Bellinger, David C; Rappaport, Leonard

    2003-01-01

    We evaluated community general education (CGE; n = 178), community special education (CSE; n = 30) and hospital-referred (HR, n = 145) children (ages 7-6 to 11-11) prospectively over a 2-year period. During this period, 17 CGE children were referred for evaluation (community referred; CR). Prior to referral, CR children performed more poorly than community-nonreferred (CNR) children on cognitive ability, academic achievement, attention problems, and information processing. CR group performance was equivalent to that of CSE and HR groups, but HR children showed poorer academic achievement. Referred children performed more poorly on all measures than nonreferred, whether they met formal diagnostic criteria for a learning disorder or not. Learning disorders may be better conceptualized as a context-dependent problem of functional adaptation than as a disability analogous to physical disabilities, raising questions about the validity of using psychometric test scores as the criterion for identification.

  15. Forensic Stable Isotope Biogeochemistry

    Science.gov (United States)

    Cerling, Thure E.; Barnette, Janet E.; Bowen, Gabriel J.; Chesson, Lesley A.; Ehleringer, James R.; Remien, Christopher H.; Shea, Patrick; Tipple, Brett J.; West, Jason B.

    2016-06-01

    Stable isotopes are being used for forensic science studies, with applications to both natural and manufactured products. In this review we discuss how scientific evidence can be used in the legal context and where the scientific progress of hypothesis revisions can be in tension with the legal expectations of widely used methods for measurements. Although this review is written in the context of US law, many of the considerations of scientific reproducibility and acceptance of relevant scientific data span other legal systems that might apply different legal principles and therefore reach different conclusions. Stable isotopes are used in legal situations for comparing samples for authenticity or evidentiary considerations, in understanding trade patterns of illegal materials, and in understanding the origins of unknown decedents. Isotope evidence is particularly useful when considered in the broad framework of physiochemical processes and in recognizing regional to global patterns found in many materials, including foods and food products, drugs, and humans. Stable isotopes considered in the larger spatial context add an important dimension to forensic science.

  16. Testing the Role of Dorsal Premotor Cortex in Auditory-Motor Association Learning Using Transcranical Magnetic Stimulation (TMS.

    Directory of Open Access Journals (Sweden)

    Carlotta Lega

    Full Text Available Interactions between the auditory and the motor systems are critical in music as well as in other domains, such as speech. The premotor cortex, specifically the dorsal premotor cortex (dPMC, seems to play a key role in auditory-motor integration, and in mapping the association between a sound and the movement used to produce it. In the present studies we tested the causal role of the dPMC in learning and applying auditory-motor associations using 1 Hz repetitive Transcranical Magnetic Stimulation (rTMS. In this paradigm, non-musicians learn a set of auditory-motor associations through melody training in two contexts: first when the sound to key-press mapping was in a conventional sequential order (low to high tones mapped onto keys from left to right, and then when it was in a novel scrambled order. Participant's ability to match the four pitches to four computer keys was tested before and after the training. In both experiments, the group that received 1 Hz rTMS over the dPMC showed no significant improvement on the pitch-matching task following training, whereas the control group (who received rTMS to visual cortex did. Moreover, in Experiment 2 where the pitch-key mapping was novel, rTMS over the dPMC also interfered with learning. These findings suggest that rTMS over dPMC disturbs the formation of auditory-motor associations, especially when the association is novel and must be learned rather explicitly. The present results contribute to a better understanding of the role of dPMC in auditory-motor integration, suggesting a critical role of dPMC in learning the link between an action and its associated sound.

  17. KNOWLEDGE TRANSFER AND LEARNING: PROBLEMS OF KNOWLEDGE TRANSFER ASSOCIATED WITH TRYING TO SHORT-CIRCUIT THE LEARNING CYCLE

    Directory of Open Access Journals (Sweden)

    Sue Newell

    2006-11-01

    Full Text Available Knowledge is considered to be a key organizational resource in the 21st century and the knowledge management ‘movement’ has alerted organizations to the fact that they should more strategically exploit their knowledge assets. Companies are thus lured by the suggestion that they can gain competitive advantage by the more astute management of their knowledge base and in particular, by the transfer of knowledge across individuals, groups and organizational units, using IT to accomplish this. In this paper, we reflect on this common view of knowledge transfer. More specifically, we question an implication of this view - essentially the possibility of short-circuiting the learning cycle, so that individuals do not have to rely on their personal or shared experiences to identify better practices, but can learn from the codified lessons of others in IT systems. More importantly, we consider the characteristics of knowledge – that knowledge is distributed, ambiguous and disruptive – that makes its transfer highly problematic. Drawing on case research, we relate this to the learning cycle (Kolb 1984 and thereby identify barriers to knowledge transfer. We conclude by considering ways of overcoming these barriers by emphasizing the importance of social systems alongside technical systems.

  18. Maximising Intercultural Learning in Short Term International Placements: Findings Associated with Orientation Programs, Guided Reflection and Immersion

    Science.gov (United States)

    Campbell, Coral J. L.; Walta, Caroline

    2015-01-01

    Short-term international practicum experience is now a feature of many university education programs in Australia in an attempt to engage students with the growing multi-cultural aspects of Australian life. The stated purposes of such practicum experiences generally highlight intercultural learning, which is associated with the development of…

  19. Are Cardiovascular Risk Factors Associated with Verbal Learning and Memory Impairment in Patients with Schizophrenia? A Cross-Sectional Study

    Directory of Open Access Journals (Sweden)

    Christophe Lancon

    2012-01-01

    Full Text Available Objective. The aim of this study is to assess the relationships of cardiovascular risk factors with verbal learning and memory in patients with schizophrenia. Methods and Design. cross-sectional study. Inclusion Criteria. Diagnosis of schizophrenia according to the DSM-IV-TR criteria. Data Collection. Sociodemographic information, clinical characteristics, anthropometric measurements, blood tests, and episodic memory using the California Verbal Learning Test (CVLT. Analysis. A multivariate analysis using multiple linear regressions was performed to determine variables that are potentially associated with verbal learning and memory. Results. One hundred and sixty-eight outpatients participated in our study. An association was found between the metabolic syndrome (MetS and memory impairment on measures of verbal learning, and short- and long-term memory. Among the different components of MeTS, hypertriglycerides, abdominal obesity, and low HDL cholesterol were the only factors associated with memory impairment. Alcohol dependence or abuse was associated with a higher rate of forgetting. Conclusion. Our findings suggest that MetS and alcohol use may be linked with memory impairment in schizophrenia. These findings provide important insights into the interdependencies of cardiovascular risk factors and cognitive disorders and support novel strategies for treating and preventing cognitive disorders in patients with schizophrenia.

  20. Impact of novel olfactory stimuli at supra and subthreshold concentrations on the perceived sweetness of sucrose after associative learning.

    Science.gov (United States)

    Labbe, David; Martin, Nathalie

    2009-10-01

    The impact of coexposure to a novel olfactory stimulation in combination with sweet taste on the construction of perceptual interaction was studied. The first objective was to explore whether a new flavoring perceived retronasally at a subthreshold concentration could enhance the perceived sweetness after a coexposure with sucrose using an approach encouraging associative learning. After validating the associative learning by showing an increase of the perceived sweetness by the flavoring at a suprathreshold concentration, we showed that the flavoring stimulation did not impact the perceived sweetness when presented at a subthreshold concentration. The second objective was to validate the absence of associative learning when subjects were exposed to the sucrose flavored solution in a context of coexposure akin to sensory profiling training. As expected, we confirmed that coexposure following sensory profiling training did not promote associative learning, probably because this approach encouraged subjects to consider the olfactory and sweet taste combination as a set of distinct qualities. The potential role of neural integration processes in these results was discussed.

  1. Types of Language Disorders in Students Classified as ED: Prevalence and Association with Learning Disabilities and Psychopathology

    Science.gov (United States)

    Benner, Gregory J.; Mattison, Richard E.; Nelson, J. Ron; Ralston, Nicole C.

    2009-01-01

    The purpose of this study was to determine the prevalence of four types of language disorders among public school students (N = 152) classified as Emotional Disturbance (ED). We also examined the association of the types of language disorders experienced by these students with specific learning disabilities and clinical levels of specific types of…

  2. Associations among Attitudes, Perceived Difficulty of Learning Science, Gender, Parents' Occupation and Students' Scientific Competencies

    Science.gov (United States)

    Chi, ShaoHui; Wang, Zuhao; Liu, Xiufeng; Zhu, Lei

    2017-01-01

    This study investigated the associations among students' attitudes towards science, students' perceived difficulty of learning science, gender, parents' occupations and their scientific competencies. A sample of 1591 (720 males and 871 females) ninth-grade students from 29 junior high schools in Shanghai completed a scientific competency test and…

  3. Variation of the gene coding for DARPP-32 (PPP1R1B) and brain connectivity during associative emotional learning

    NARCIS (Netherlands)

    Curcic-Blake, Branislava; Swart, Marte; Ter Horst, Gert J.; Langers, Dave R. M.; Kema, Ido P.; Aleman, Andre

    2012-01-01

    Associative emotional learning, which is important for the social emotional functioning of individuals and is often impaired in psychiatric illnesses, is in part mediated by dopamine and glutamate pathways in the brain. The protein DARPP-32 is involved in the regulation of dopaminergic and

  4. An Empirical Examination of the Association between Multiple Intelligences and Language Learning Self-Efficacy among TEFL University Students

    Science.gov (United States)

    Moafian, Fatemeh; Ebrahimi, Mohammad Reza

    2015-01-01

    The current study investigated the association between multiple intelligences and language learning efficacy expectations among TEFL (Teaching English as a Foreign Language) university students. To fulfill the aim of the study, 108 junior and senior TEFL students were asked to complete the "Multiple Intelligence Developmental Assessment…

  5. Increased entorhinal-prefrontal theta synchronization parallels decreased entorhinal-hippocampal theta synchronization during learning and consolidation of associative memory.

    Directory of Open Access Journals (Sweden)

    Kaori eTakehara-Nishiuchi

    2012-01-01

    Full Text Available Memories are thought to be encoded as a distributed representation in the neocortex. The medial prefrontal cortex (mPFC has been shown to support the expression of memories that initially depend on the hippocampus (HPC, yet the mechanisms by which the HPC and mPFC access the distributed representations in the neocortex are unknown. By measuring phase synchronization of local field potential (LFP oscillations, we found that learning initiated changes in neuronal communication of the HPC and mPFC with the lateral entorhinal cortex (LEC, an area that is connected with many other neocortical regions. LFPs were recorded simultaneously from the three brain regions while rats formed an association between an auditory stimulus (CS and eyelid stimulation (US in a trace eyeblink conditioning paradigm, as well as during retention one month following learning. Over the course of learning, theta oscillations in the LEC and mPFC became strongly synchronized following the presentation of the CS on trials in which rats exhibited a conditioned response (CR, and this strengthened synchronization was also observed during retention one month after learning. In contrast, CS-evoked theta synchronization between the LEC and HPC decreased with learning. Our results suggest that the communication between the LEC and mPFC is strengthened with learning whereas the communication between the LEC and HPC is concomitantly weakened, suggesting that enhanced LEC-mPFC communication may be a key process for theoretically-proposed neocortical reorganization accompanying encoding and consolidation of a memory.

  6. Highly scalable multichannel mesh electronics for stable chronic brain electrophysiology.

    Science.gov (United States)

    Fu, Tian-Ming; Hong, Guosong; Viveros, Robert D; Zhou, Tao; Lieber, Charles M

    2017-11-21

    Implantable electrical probes have led to advances in neuroscience, brain-machine interfaces, and treatment of neurological diseases, yet they remain limited in several key aspects. Ideally, an electrical probe should be capable of recording from large numbers of neurons across multiple local circuits and, importantly, allow stable tracking of the evolution of these neurons over the entire course of study. Silicon probes based on microfabrication can yield large-scale, high-density recording but face challenges of chronic gliosis and instability due to mechanical and structural mismatch with the brain. Ultraflexible mesh electronics, on the other hand, have demonstrated negligible chronic immune response and stable long-term brain monitoring at single-neuron level, although, to date, it has been limited to 16 channels. Here, we present a scalable scheme for highly multiplexed mesh electronics probes to bridge the gap between scalability and flexibility, where 32 to 128 channels per probe were implemented while the crucial brain-like structure and mechanics were maintained. Combining this mesh design with multisite injection, we demonstrate stable 128-channel local field potential and single-unit recordings from multiple brain regions in awake restrained mice over 4 mo. In addition, the newly integrated mesh is used to validate stable chronic recordings in freely behaving mice. This scalable scheme for mesh electronics together with demonstrated long-term stability represent important progress toward the realization of ideal implantable electrical probes allowing for mapping and tracking single-neuron level circuit changes associated with learning, aging, and neurodegenerative diseases. Copyright © 2017 the Author(s). Published by PNAS.

  7. Perceived and post-traumatic stress are associated with decreased learning, memory, and fluency in HIV-infected women.

    Science.gov (United States)

    Rubin, Leah H; Cook, Judith A; Springer, Gayle; Weber, Kathleen M; Cohen, Mardge H; Martin, Eileen M; Valcour, Victor G; Benning, Lorie; Alden, Christine; Milam, Joel; Anastos, Kathryn; Young, Mary A; Gustafson, Deborah R; Sundermann, Erin E; Maki, Pauline M

    2017-08-28

    Psychological risk factors (PRFs) are associated with impaired learning and memory in HIV-infected (HIV+) women. We determined the dynamic nature of the effects of PRFs and HIV serostatus on learning and memory over time. Multi-center, prospective cohort study METHODS:: Every two years between 2009 and 2013 (3 times), 646 HIV+ and 300 demographically-similar HIV-uninfected (HIV-) women from the Women's Interagency HIV Study completed neuropsychological (NP) testing and questionnaires measuring PRFs (perceived stress, post-traumatic stress disorder (PTSD) symptoms, depressive symptoms). Using mixed-effects regressions, we examined separate and interactive associations between HIV-serostatus and PRFs on performance over time. HIV+ and HIV- women had similar rates of PRFs. Fluency was the only domain where performance over time depended on the combined influence of HIV-serostatus and stress or PTSD (p's stress and PTSD were associated with a greater cognitive decline in performance (p's stress and PTSD. Irrespective of time, performance on learning and memory depended on the combined influence of HIV-serostatus and stress or PTSD (p's ≤ 0.05). In the context of HIV, stress and PTSD were negatively associated with performance. Effects were pronounced on learning among HIV+ women without effective treatment or viral suppression. Regardless of time or HIV-serostatus, all PRFs were associated with lower speed, global NP, and executive function. More than depression, perceived stress and PTSD symptoms are treatment targets to potentially improve fluency, learning, and memory in women living with HIV particularly when HIV treatment is not optimal.

  8. Olfactory enrichment and scent cue associative learning in captive birds of prey.

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    Nelson Slater, Melissa; Hauber, Mark E

    2017-03-01

    As the use of enrichment in zoos has become a standardized husbandry practice, the continued improvement of enrichment programs should be concomitant with empirical validation of those practices. The role of scent as enrichment remains an unexplored avenue for many bird species. We conducted a multi-phase experiment to introduce wrapped food packages and scent cuing to indicate food presence into the exhibits of several birds of prey species at the Bronx Zoo, New York City, to assess if scent can function as enrichment in these species. Our research found support for these birds associating a novel scent cue from a package with the presence of food inside. When tested with sham (empty) packages, these individuals more often and more extensively handled scented versus unscented packages. Overall, these results indicate the ability of some our small sample of individuals to learn olfactory cues and provide support for trials to include olfactory enrichment as a potential part of the daily routine for some birds of prey in zoo settings. © 2017 Wiley Periodicals, Inc.

  9. Transcranial Direct Current Stimulation Facilitates Associative Learning and Alters Functional Connectivity in the Primate Brain.

    Science.gov (United States)

    Krause, Matthew R; Zanos, Theodoros P; Csorba, Bennett A; Pilly, Praveen K; Choe, Jaehoon; Phillips, Matthew E; Datta, Abhishek; Pack, Christopher C

    2017-10-23

    There has been growing interest in transcranial direct current stimulation (tDCS), a non-invasive technique purported to modulate neural activity via weak, externally applied electric fields. Although some promising preliminary data have been reported for applications ranging from stroke rehabilitation to cognitive enhancement, little is known about how tDCS affects the human brain, and some studies have concluded that it may have no effect at all. Here, we describe a macaque model of tDCS that allows us to simultaneously examine the effects of tDCS on brain activity and behavior. We find that applying tDCS to right prefrontal cortex improves monkeys' performance on an associative learning task. While firing rates do not change within the targeted area, tDCS does induce large low-frequency oscillations in the underlying tissue. These oscillations alter functional connectivity, both locally and between distant brain areas, and these long-range changes correlate with tDCS's effects on behavior. Together, these results are consistent with the idea that tDCS leads to widespread changes in brain activity and suggest that it may be a valuable method for cheaply and non-invasively altering functional connectivity in humans. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Associative learning mechanisms underpinning the transition from recreational drug use to addiction.

    Science.gov (United States)

    Hogarth, Lee; Balleine, Bernard W; Corbit, Laura H; Killcross, Simon

    2013-04-01

    Learning theory proposes that drug seeking is a synthesis of multiple controllers. Whereas goal-directed drug seeking is determined by the anticipated incentive value of the drug, habitual drug seeking is elicited by stimuli that have formed a direct association with the response. Moreover, drug-paired stimuli can transfer control over separately trained drug seeking responses by retrieving an expectation of the drug's identity (specific transfer) or incentive value (general transfer). This review covers outcome devaluation and transfer of stimulus-control procedures in humans and animals, which isolate the differential governance of drug seeking by these four controllers following various degrees of contingent and noncontingent drug exposure. The neural mechanisms underpinning these four controllers are also reviewed. These studies suggest that although initial drug seeking is goal-directed, chronic drug exposure confers a progressive loss of control over action selection by specific outcome representations (impaired outcome devaluation and specific transfer), and a concomitant increase in control over action selection by antecedent stimuli (enhanced habit and general transfer). The prefrontal cortex and mediodorsal thalamus may play a role in this drug-induced transition to behavioral autonomy. © 2012 New York Academy of Sciences.

  11. Literature mining of protein-residue associations with graph rules learned through distant supervision

    Directory of Open Access Journals (Sweden)

    Ravikumar KE

    2012-10-01

    Full Text Available Abstract Background We propose a method for automatic extraction of protein-specific residue mentions from the biomedical literature. The method searches text for mentions of amino acids at specific sequence positions and attempts to correctly associate each mention with a protein also named in the text. The methods presented in this work will enable improved protein functional site extraction from articles, ultimately supporting protein function prediction. Our method made use of linguistic patterns for identifying the amino acid residue mentions in text. Further, we applied an automated graph-based method to learn syntactic patterns corresponding to protein-residue pairs mentioned in the text. We finally present an approach to automated construction of relevant training and test data using the distant supervision model. Results The performance of the method was assessed by extracting protein-residue relations from a new automatically generated test set of sentences containing high confidence examples found using distant supervision. It achieved a F-measure of 0.84 on automatically created silver corpus and 0.79 on a manually annotated gold data set for this task, outperforming previous methods. Conclusions The primary contributions of this work are to (1 demonstrate the effectiveness of distant supervision for automatic creation of training data for protein-residue relation extraction, substantially reducing the effort and time involved in manual annotation of a data set and (2 show that the graph-based relation extraction approach we used generalizes well to the problem of protein-residue association extraction. This work paves the way towards effective extraction of protein functional residues from the literature.

  12. Literature mining of protein-residue associations with graph rules learned through distant supervision.

    Science.gov (United States)

    Ravikumar, Ke; Liu, Haibin; Cohn, Judith D; Wall, Michael E; Verspoor, Karin

    2012-10-05

    We propose a method for automatic extraction of protein-specific residue mentions from the biomedical literature. The method searches text for mentions of amino acids at specific sequence positions and attempts to correctly associate each mention with a protein also named in the text. The methods presented in this work will enable improved protein functional site extraction from articles, ultimately supporting protein function prediction. Our method made use of linguistic patterns for identifying the amino acid residue mentions in text. Further, we applied an automated graph-based method to learn syntactic patterns corresponding to protein-residue pairs mentioned in the text. We finally present an approach to automated construction of relevant training and test data using the distant supervision model. The performance of the method was assessed by extracting protein-residue relations from a new automatically generated test set of sentences containing high confidence examples found using distant supervision. It achieved a F-measure of 0.84 on automatically created silver corpus and 0.79 on a manually annotated gold data set for this task, outperforming previous methods. The primary contributions of this work are to (1) demonstrate the effectiveness of distant supervision for automatic creation of training data for protein-residue relation extraction, substantially reducing the effort and time involved in manual annotation of a data set and (2) show that the graph-based relation extraction approach we used generalizes well to the problem of protein-residue association extraction. This work paves the way towards effective extraction of protein functional residues from the literature.

  13. Examining the direct and indirect effects of visual-verbal paired associate learning on Chinese word reading.

    Science.gov (United States)

    Georgiou, George; Liu, Cuina; Xu, Shiyang

    2017-08-01

    Associative learning, traditionally measured with paired associate learning (PAL) tasks, has been found to predict reading ability in several languages. However, it remains unclear whether it also predicts word reading in Chinese, which is known for its ambiguous print-sound correspondences, and whether its effects are direct or indirect through the effects of other reading-related skills such as phonological awareness and rapid naming. Thus, the purpose of this study was to examine the direct and indirect effects of visual-verbal PAL on word reading in an unselected sample of Chinese children followed from the second to the third kindergarten year. A sample of 141 second-year kindergarten children (71 girls and 70 boys; mean age=58.99months, SD=3.17) were followed for a year and were assessed at both times on measures of visual-verbal PAL, rapid naming, and phonological awareness. In the third kindergarten year, they were also assessed on word reading. The results of path analysis showed that visual-verbal PAL exerted a significant direct effect on word reading that was independent of the effects of phonological awareness and rapid naming. However, it also exerted significant indirect effects through phonological awareness. Taken together, these findings suggest that variations in cross-modal associative learning (as measured by visual-verbal PAL) place constraints on the development of word recognition skills irrespective of the characteristics of the orthography children are learning to read. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Impaired associative fear learning in mice with complete loss or haploinsufficiency of AMPA GluR1 receptors

    Directory of Open Access Journals (Sweden)

    Michael Feyder

    2007-12-01

    Full Text Available There is compelling evidence that L-alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA glutamate receptors containing the GluR1 subunit contribute to the molecular mechanisms associated with learning. AMPA GluR1 glutamate receptor knockout mice (KO exhibit abnormal hippocampal and amygdala plasticity, and deficits on various assays for cognition including Pavlovian fear conditioning. Here we examined associative fear learning in mice with complete absence (KO or partial loss (heterozygous mutant, HET of GluR1 on multiple fear conditioning paradigms. After multi-trial delay or trace conditioning, KO displayed impaired tone and context fear recall relative to WT, whereas HET were normal. After one-trial delay conditioning, both KO and HET showed impaired tone and context recall. HET and KO showed normal nociceptive sensitivity in the hot plate and tail flick tests. These data demonstrate that the complete absence of GluR1 subunit-containing receptors prevents the formation of associative fear memories, while GluR1 haploinsufficiency is sufficient to impair one-trial fear learning. These findings support growing evidence of a major role for GluR1-containing AMPA receptors in amygdalamediated forms of learning and memory.

  15. Phoneme Awareness, Visual-Verbal Paired-Associate Learning, and Rapid Automatized Naming as Predictors of Individual Differences in Reading Ability

    Science.gov (United States)

    Warmington, Meesha; Hulme, Charles

    2012-01-01

    This study examines the concurrent relationships between phoneme awareness, visual-verbal paired-associate learning, rapid automatized naming (RAN), and reading skills in 7- to 11-year-old children. Path analyses showed that visual-verbal paired-associate learning and RAN, but not phoneme awareness, were unique predictors of word recognition,…

  16. Nicotine Withdrawal Disrupts Contextual Learning but Not Recall of Prior Contextual Associations: Implications for Nicotine Addiction

    OpenAIRE

    Portugal, George S.; Gould, Thomas J.

    2008-01-01

    Interactions between nicotine and learning could contribute to nicotine addiction. Although previous research indicates that nicotine withdrawal disrupts contextual learning, the effects of nicotine withdrawal on contextual memories acquired before withdrawal are unknown. The present study investigated whether nicotine withdrawal disrupted recall of prior contextual memories by examining the effects of nicotine withdrawal on recall of nicotine conditioned place preference (CPP) and contextual...

  17. Chronically Increased G[subscript s][alpha] Signaling Disrupts Associative and Spatial Learning

    Science.gov (United States)

    Bourtchouladze, Rusiko; Patterson, Susan L.; Kelly, Michele P.; Kreibich, Arati; Kandel, Eric R.; Abel, Ted

    2006-01-01

    The cAMP/PKA pathway plays a critical role in learning and memory systems in animals ranging from mice to "Drosophila" to "Aplysia." Studies of olfactory learning in "Drosophila" suggest that altered expression of either positive or negative regulators of the cAMP/PKA signaling pathway beyond a certain optimum range may be deleterious. Here we…

  18. A computational model associating learning process, word attributes, and age of acquisition.

    Science.gov (United States)

    Hidaka, Shohei

    2013-01-01

    We propose a new model-based approach linking word learning to the age of acquisition (AoA) of words; a new computational tool for understanding the relationships among word learning processes, psychological attributes, and word AoAs as measures of vocabulary growth. The computational model developed describes the distinct statistical relationships between three theoretical factors underpinning word learning and AoA distributions. Simply put, this model formulates how different learning processes, characterized by change in learning rate over time and/or by the number of exposures required to acquire a word, likely result in different AoA distributions depending on word type. We tested the model in three respects. The first analysis showed that the proposed model accounts for empirical AoA distributions better than a standard alternative. The second analysis demonstrated that the estimated learning parameters well predicted the psychological attributes, such as frequency and imageability, of words. The third analysis illustrated that the developmental trend predicted by our estimated learning parameters was consistent with relevant findings in the developmental literature on word learning in children. We further discuss the theoretical implications of our model-based approach.

  19. Metacognitive Monkeys or Associative Animals? Simple Reinforcement Learning Explains Uncertainty in Nonhuman Animals

    Science.gov (United States)

    Le Pelley, M. E.

    2012-01-01

    Monkeys will selectively and adaptively learn to avoid the most difficult trials of a perceptual discrimination learning task. Couchman, Coutinho, Beran, and Smith (2010) have recently demonstrated that this pattern of responding does not depend on animals receiving trial-by-trial feedback for their responses; it also obtains if experience of the…

  20. Associations of Subjective Immersion, Immersion Subfactors, and Learning Outcomes in the Revised Game Engagement Model

    Science.gov (United States)

    Barclay, Paul A.; Bowers, Clint

    2018-01-01

    Serious Educational Video Games (SEGs) play a large role in education for both children and adults. However, the budget for SEGs is typically lower than traditional entertainment video games, bringing with it the need to optimize the learning experience. This article looks at the role game immersion plays in improving learning outcomes, using the…

  1. Psychological and Organizational Variables Associated with Workplace Learning in Small and Medium Manufacturing Businesses in Korea

    Science.gov (United States)

    Moon, Se-Yeon; Na, Seung-Il

    2009-01-01

    The purpose of this study was to determine the relationship between workplace learning and psychological variables, such as learning competency, motivation, curiosity, self-esteem and locus of control, and organizational variables, such as centralization of power, formality, merit system and communication. The studied population consisted entirely…

  2. Indicators of early and late processing reveal the importance of within-trial-time for theories of associative learning.

    Science.gov (United States)

    Lachnit, Harald; Thorwart, Anna; Schultheis, Holger; Lotz, Anja; Koenig, Stephan; Uengoer, Metin

    2013-01-01

    In four human learning experiments (Pavlovian skin conductance, causal learning, speeded classification task), we evaluated several associative learning theories that assume either an elemental (modified unique cue model and Harris' model) or a configural (Pearce's configural theory and an extension of it) form of stimulus processing. The experiments used two modified patterning problems (A/B/C+, AB/BC/AC+ vs. ABC-; A+, BC+ vs. ABC-). Pearce's configural theory successfully predicted all of our data reflecting early stimulus processing, while the predictions of the elemental theories were in accord with all of our data reflecting later stages of stimulus processing. Our results suggest that the form of stimulus representation depends on the amount of time available for stimulus processing. Our findings highlight the necessity to investigate stimulus processing during conditioning on a finer time scale than usually done in contemporary research.

  3. Protein dynamics associated with failed and rescued learning in the Ts65Dn mouse model of Down syndrome.

    Directory of Open Access Journals (Sweden)

    Md Mahiuddin Ahmed

    Full Text Available Down syndrome (DS is caused by an extra copy of human chromosome 21 (Hsa21. Although it is the most common genetic cause of intellectual disability (ID, there are, as yet, no effective pharmacotherapies. The Ts65Dn mouse model of DS is trisomic for orthologs of ∼55% of Hsa21 classical protein coding genes. These mice display many features relevant to those seen in DS, including deficits in learning and memory (L/M tasks requiring a functional hippocampus. Recently, the N-methyl-D-aspartate (NMDA receptor antagonist, memantine, was shown to rescue performance of the Ts65Dn in several L/M tasks. These studies, however, have not been accompanied by molecular analyses. In previous work, we described changes in protein expression induced in hippocampus and cortex in control mice after exposure to context fear conditioning (CFC, with and without memantine treatment. Here, we extend this analysis to Ts65Dn mice, measuring levels of 85 proteins/protein modifications, including components of MAP kinase and MTOR pathways, and subunits of NMDA receptors, in cortex and hippocampus of Ts65Dn mice after failed learning in CFC and after learning was rescued by memantine. We show that, compared with wild type littermate controls, (i of the dynamic responses seen in control mice in normal learning, >40% also occur in Ts65Dn in failed learning or are compensated by baseline abnormalities, and thus are considered necessary but not sufficient for successful learning, and (ii treatment with memantine does not in general normalize the initial protein levels but instead induces direct and indirect responses in approximately half the proteins measured and results in normalization of the endpoint protein levels. Together, these datasets provide a first view of the complexities associated with pharmacological rescue of learning in the Ts65Dn. Extending such studies to additional drugs and mouse models of DS will aid in identifying pharmacotherapies for effective

  4. Marginally Stable Nuclear Burning

    Science.gov (United States)

    Strohmayer, Tod E.; Altamirano, D.

    2012-01-01

    Thermonuclear X-ray bursts result from unstable nuclear burning of the material accreted on neutron stars in some low mass X-ray binaries (LMXBs). Theory predicts that close to the boundary of stability oscillatory burning can occur. This marginally stable regime has so far been identified in only a small number of sources. We present Rossi X-ray Timing Explorer (RXTE) observations of the bursting, high- inclination LMXB 4U 1323-619 that reveal for the first time in this source the signature of marginally stable burning. The source was observed during two successive RXTE orbits for approximately 5 ksec beginning at 10:14:01 UTC on March 28, 2011. Significant mHz quasi- periodic oscillations (QPO) at a frequency of 8.1 mHz are detected for approximately 1600 s from the beginning of the observation until the occurrence of a thermonuclear X-ray burst at 10:42:22 UTC. The mHz oscillations are not detected following the X-ray burst. The average fractional rms amplitude of the mHz QPOs is 6.4% (3 - 20 keV), and the amplitude increases to about 8% below 10 keV.This phenomenology is strikingly similar to that seen in the LMXB 4U 1636-53. Indeed, the frequency of the mHz QPOs in 4U 1323-619 prior to the X-ray burst is very similar to the transition frequency between mHz QPO and bursts found in 4U 1636-53 by Altamirano et al. (2008). These results strongly suggest that the observed QPOs in 4U 1323-619 are, like those in 4U 1636-53, due to marginally stable nuclear burning. We also explore the dependence of the energy spectrum on the oscillation phase, and we place the present observations within the context of the spectral evolution of the accretion-powered flux from the source.

  5. Non-linguistic learning and aphasia: Evidence from a paired associate and feedback-based task

    Science.gov (United States)

    Vallila-Rohter, Sofia; Kiran, Swathi

    2013-01-01

    Though aphasia is primarily characterized by impairments in the comprehension and/or expression of language, research has shown that patients with aphasia also show deficits in cognitive-linguistic domains such as attention, executive function, concept knowledge and memory (Helm-Estabrooks, 2002 for review). Research in aphasia suggests that cognitive impairments can impact the online construction of language, new verbal learning, and transactional success (Freedman & Martin, 2001; Hula & McNeil, 2008; Ramsberger, 2005). In our research, we extend this hypothesis to suggest that general cognitive deficits influence progress with therapy. The aim of our study is to explore learning, a cognitive process that is integral to relearning language, yet underexplored in the field of aphasia rehabilitation. We examine non-linguistic category learning in patients with aphasia (n=19) and in healthy controls (n=12), comparing feedback and non-feedback based instruction. Participants complete two computer-based learning tasks that require them to categorize novel animals based on the percentage of features shared with one of two prototypes. As hypothesized, healthy controls showed successful category learning following both methods of instruction. In contrast, only 60% of our patient population demonstrated successful non-linguistic category learning. Patient performance was not predictable by standardized measures of cognitive ability. Results suggest that general learning is affected in aphasia and is a unique, important factor to consider in the field of aphasia rehabilitation. PMID:23127795

  6. Relative prediction error and protection from attentional blink in human associative learning.

    Science.gov (United States)

    Glautier, Steven; Shih, Shui-L

    2015-01-01

    The relationship between predictive learning and attentional processing was investigated in two experiments. During a learning procedure participants viewed rapid serial visual presentation (RSVP) of stimuli in the context of a choice-reaction-time (CRT) task. Salient stimuli in the RSVP streams were either predictive or non-predictive for the outcome of the CRT task. Following this procedure we measured attentional blink (AB) to the predictive and non-predictive stimuli. In Experiment 1, despite the use of a large sample and checks demonstrating the validity of the learning procedure and the AB measure, we did not observe reduced AB for predictive stimuli. In contrast, in Experiment 2, where the predictive stimuli occurred alongside salient non-predictive comparison stimuli, we did find less AB for predictive than for non-predictive stimuli. Our results support an attentional model of learning in which relative prediction error is used to increase learning rates for good predictors and reduce learning rates for poor predictors and provide confirmation of the AB learning effect.

  7. ASSOCIATION BETWEEN AFFECTS AND REPRESENTATIONS INVOLVED IN THE SCHOOL LEARNING ENVIRONMENT

    Directory of Open Access Journals (Sweden)

    Andreia Osti

    2017-04-01

    Full Text Available This study assumes that the affective dimensions involves the process of planning and developing pedagogical practices and are an important factor in determining the nature of relations between the students and the various objects of knowledge. In this sense, the study aimed to analyze how students represent the affective aspects of both the teaching and learning process and what are their perceptions of the learning environment. The participants were 120 students of the 5th year of elementary school of public schools in the metropolitan region of Campinas, 60 of those students having satisfactory academic performance and 60 having learning disabilities. To gather the data, three instruments were used: “Psychopedagogical Educational Par Proof”, “AffectionsZanon Scale” and “Teacher Expectations Scale”. The results revealed that students with learning disabilities differ significantly from those with adequate performance. Students with learning difficulties establish fewer ties with the formal school learning and for their teachers and this portrays non-school situations while students with satisfactory performance have a better understanding of the expectations of their teachers and this shows that they have a more emotional relationship with the school environment. It is believed that this study contributes to the understanding of the relationship between the feelings experienced by students in the context of the classroom and its implications for the academic performance of the same. Keywords: Positive Psychology. Interpersonal relationships. Learning experiences.

  8. Non-linguistic learning and aphasia: evidence from a paired associate and feedback-based task.

    Science.gov (United States)

    Vallila-Rohter, Sofia; Kiran, Swathi

    2013-01-01

    Though aphasia is primarily characterized by impairments in the comprehension and/or expression of language, research has shown that patients with aphasia also show deficits in cognitive-linguistic domains such as attention, executive function, concept knowledge and memory. Research in aphasia suggests that cognitive impairments can impact the online construction of language, new verbal learning, and transactional success. In our research, we extend this hypothesis to suggest that general cognitive deficits influence progress with therapy. The aim of our study is to explore learning, a cognitive process that is integral to relearning language, yet underexplored in the field of aphasia rehabilitation. We examine non-linguistic category learning in patients with aphasia (n=19) and in healthy controls (n=12), comparing feedback and non-feedback based instruction. Participants complete two computer-based learning tasks that require them to categorize novel animals based on the percentage of features shared with one of two prototypes. As hypothesized, healthy controls showed successful category learning following both methods of instruction. In contrast, only 60% of our patient population demonstrated successful non-linguistic category learning. Patient performance was not predictable by standardized measures of cognitive ability. Results suggest that general learning is affected in aphasia and is a unique, important factor to consider in the field of aphasia rehabilitation. Copyright © 2012 Elsevier Ltd. All rights reserved.

  9. Bactrocera oleae-induced olive VOCs routing mate searching in Psyttalia concolor males: impact of associative learning.

    Science.gov (United States)

    Giunti, G; Benelli, G; Palmeri, V; Canale, A

    2018-02-01

    Olfaction is a key sense routing foraging behaviour in parasitoids. Preferences for food, mate and host stimuli can be innate in parasitic wasps. Alternatively, learning-mediated mechanisms play a crucial role. Females of the braconid parasitoid Psyttalia concolor exploit olfactory cues arising from tephritid hosts and related microhabitats. However, little is known on the olfactory stimuli routing males searching for mates. In this study, we focused on the attractiveness of Bactrocera oleae-induced olive volatiles towards P. concolor males. Furthermore, we evaluated learning occurrence in virgin males, when trained for selected unattractive volatile organic compounds (VOCs) associated with mate rewards. (E)-β-Ocimene, α-pinene and limonene attracted virgin males in Y-tube bioassays. Unattractive VOCs evoked positive chemotaxis after associative learning training. P. concolor males exposed to VOCs during a successful or unsuccessful mating, showed short-term preference for these VOCs (fast consolidation into protein dependent long-term memory, appearing after 24 h. On the other hand, males experiencing a less valuable training experience (i.e. unsuccessful courtship), did not show consolidated memory after 24 h. Overall, our findings suggest that P. concolor virgin males may exploit VOCs from the host microhabitat to boost their mate searching activity, thus their reproductive success. However, since learning is a costly process, P. concolor males retained durable memories just in presence of a valuable reward, thus avoiding maladaptive behaviours.

  10. Cognitive specialization for learning faces is associated with shifts in the brain transcriptome of a social wasp.

    Science.gov (United States)

    Berens, Ali J; Tibbetts, Elizabeth A; Toth, Amy L

    2017-06-15

    The specialized ability to learn and recall individuals based on distinct facial features is known in only a few, large-brained social taxa. Social paper wasps in the genus Polistes are the only insects known to possess this form of cognitive specialization. We analyzed genome-wide brain gene expression during facial and pattern training for two species of paper wasps ( P. fuscatus , which has face recognition, and P. metricus , which does not) using RNA sequencing. We identified 237 transcripts associated with face specialization in P. fuscatus , including some transcripts involved in neuronal signaling (serotonin receptor and tachykinin). Polistes metricus that learned faces (without specialized learning) and P. fuscatus in social interactions with familiar partners (from a previous study) showed distinct sets of brain differentially expressed transcripts. These data suggest face specialization in P. fuscatus is related to shifts in the brain transcriptome associated with genes distinct from those related to general visual learning and social interactions. © 2017. Published by The Company of Biologists Ltd.

  11. A process-based approach to characterizing the effect of acute alprazolam challenge on visual paired associate learning and memory in healthy older adults.

    Science.gov (United States)

    Pietrzak, Robert H; Scott, James Cobb; Harel, Brian T; Lim, Yen Ying; Snyder, Peter J; Maruff, Paul

    2012-11-01

    Alprazolam is a benzodiazepine that, when administered acutely, results in impairments in several aspects of cognition, including attention, learning, and memory. However, the profile (i.e., component processes) that underlie alprazolam-related decrements in visual paired associate learning has not been fully explored. In this double-blind, placebo-controlled, randomized cross-over study of healthy older adults, we used a novel, "process-based" computerized measure of visual paired associate learning to examine the effect of a single, acute 1-mg dose of alprazolam on component processes of visual paired associate learning and memory. Acute alprazolam challenge was associated with a large magnitude reduction in visual paired associate learning and memory performance (d = 1.05). Process-based analyses revealed significant increases in distractor, exploratory, between-search, and within-search error types. Analyses of percentages of each error type suggested that, relative to placebo, alprazolam challenge resulted in a decrease in the percentage of exploratory errors and an increase in the percentage of distractor errors, both of which reflect memory processes. Results of this study suggest that acute alprazolam challenge decreases visual paired associate learning and memory performance by reducing the strength of the association between pattern and location, which may reflect a general breakdown in memory consolidation, with less evidence of reductions in executive processes (e.g., working memory) that facilitate visual paired associate learning and memory. Copyright © 2012 John Wiley & Sons, Ltd.

  12. Modeling the behavioral substrates of associate learning and memory - Adaptive neural models

    Science.gov (United States)

    Lee, Chuen-Chien

    1991-01-01

    Three adaptive single-neuron models based on neural analogies of behavior modification episodes are proposed, which attempt to bridge the gap between psychology and neurophysiology. The proposed models capture the predictive nature of Pavlovian conditioning, which is essential to the theory of adaptive/learning systems. The models learn to anticipate the occurrence of a conditioned response before the presence of a reinforcing stimulus when training is complete. Furthermore, each model can find the most nonredundant and earliest predictor of reinforcement. The behavior of the models accounts for several aspects of basic animal learning phenomena in Pavlovian conditioning beyond previous related models. Computer simulations show how well the models fit empirical data from various animal learning paradigms.

  13. An Architecture for Emotional and Context-Aware Associative Learning for Robot Companions

    OpenAIRE

    Rizzi Raymundo, C.; Johnson, C. G.; Vargas, P. A.

    2015-01-01

    This work proposes a theoretical architectural model based on the brain's fear learning system with the purpose of generating artificial fear conditioning at both stimuli and context abstraction levels in robot companions. The proposed architecture is inspired by the different brain regions involved in fear learning, here divided into four modules that work in an integrated and parallel manner: the sensory system, the amygdala system, the hippocampal system and the working memory. Each of the...

  14. Motor learning in a complex balance task and associated neuroplasticity: a comparison between endurance athletes and nonathletes.

    Science.gov (United States)

    Seidel, Oliver; Carius, Daniel; Kenville, Rouven; Ragert, Patrick

    2017-09-01

    Studies suggested that motor expertise is associated with functional and structural brain alterations, which positively affect sensorimotor performance and learning capabilities. The purpose of the present study was to unravel differences in motor skill learning and associated functional neuroplasticity between endurance athletes (EA) and nonathletes (NA). For this purpose, participants had to perform a multimodal balance task (MBT) training on 2 sessions, which were separated by 1 wk. Before and after MBT training, a static balance task (SBT) had to be performed. MBT-induced functional neuroplasticity and neuromuscular alterations were assessed by means of functional near-infrared spectroscopy (fNIRS) and electromyography (EMG) during SBT performance. We hypothesized that EA would showed superior initial SBT performance and stronger MBT-induced improvements in SBT learning rates compared with NA. On a cortical level, we hypothesized that MBT training would lead to differential learning-dependent functional changes in motor-related brain regions [such as primary motor cortex (M1)] during SBT performance. In fact, EA showed superior initial SBT performance, whereas learning rates did not differ between groups. On a cortical level, fNIRS recordings (time × group interaction) revealed a stronger MBT-induced decrease in left M1 and inferior parietal lobe (IPL) for deoxygenated hemoglobin in EA. Even more interesting, learning rates were correlated with fNIRS changes in right M1/IPL. On the basis of these findings, we provide novel evidence for superior MBT training-induced functional neuroplasticity in highly trained athletes. Future studies should investigate these effects in different sports disciplines to strengthen previous work on experience-dependent neuroplasticity. NEW & NOTEWORTHY Motor expertise is associated with functional/structural brain plasticity. How such neuroplastic reorganization translates into altered motor learning processes remains elusive. We

  15. How organizational learning is associated with patient rights: a qualitative content analysis.

    Science.gov (United States)

    Heidari, Shahin; Nayeri, Nahid Dehghan; Ravari, Ali; Sabzevari, Sakineh

    2016-01-01

    Nowadays, patient rights, particularly receiving favorable health care based on modern knowledge, informed consent, and privacy, are important issues in health care delivery systems. Organizational learning is considered an important factor influencing health care quality and patient rights. However, there is little evidence regarding this issue. The present study was conducted to explore the role of organizational learning in patient rights from clinical nurses' viewpoint. This qualitative study was conducted through conventional content analysis. In total, 18 nurses who met the inclusion criteria participated in this study through purposive sampling with maximum variation. Data were gathered through 20 in-depth, semi-structured interviews, which continued until data saturation was achieved. Data collection also included constant and simultaneous comparative analyses. Data analysis led to four major themes: conservation of patient safety, providing favorable care, being the patient's advocate, and informing the patients. All the participants believed that organizational learning could play a vital role in respecting patient rights and interests. Participants believed that their efforts to conduct organizational learning, tried to improve respecting the patient rights via conservation of patient safety, trying to improve quality of care, being an advocate, and informing the patient. It would be appreciable if nursing managers honored the commitment of the nurses for learning, highlight their role as defenders of patient rights, and encourage them to initiate organizational learning.

  16. How organizational learning is associated with patient rights: a qualitative content analysis

    Directory of Open Access Journals (Sweden)

    Shahin Heidari

    2016-07-01

    Full Text Available Background: Nowadays, patient rights, particularly receiving favorable health care based on modern knowledge, informed consent, and privacy, are important issues in health care delivery systems. Organizational learning is considered an important factor influencing health care quality and patient rights. However, there is little evidence regarding this issue. Objective: The present study was conducted to explore the role of organizational learning in patient rights from clinical nurses’ viewpoint. Design: This qualitative study was conducted through conventional content analysis. In total, 18 nurses who met the inclusion criteria participated in this study through purposive sampling with maximum variation. Data were gathered through 20 in-depth, semi-structured interviews, which continued until data saturation was achieved. Data collection also included constant and simultaneous comparative analyses. Results: Data analysis led to four major themes: conservation of patient safety, providing favorable care, being the patient's advocate, and informing the patients. All the participants believed that organizational learning could play a vital role in respecting patient rights and interests. Conclusions: Participants believed that their efforts to conduct organizational learning, tried to improve respecting the patient rights via conservation of patient safety, trying to improve quality of care, being an advocate, and informing the patient. It would be appreciable if nursing managers honored the commitment of the nurses for learning, highlight their role as defenders of patient rights, and encourage them to initiate organizational learning.

  17. Developing clinically savvy nursing students: an evaluation of problem-based learning in an associate degree program.

    Science.gov (United States)

    Jones, Marcia

    2008-01-01

    Faculty in an associate degree nursing program at a community college in NewYork City noted that nursing students lacked critical analysis, problem-solving, and decision-making skills and the reflective ability essential to applying nursing knowledge in clinical situations. This study reports on the use of problem-based learning as a teaching strategy and its impact on the development of critical thinking and communication skills in nursing students.

  18. Confidence-Based Data Association and Discriminative Deep Appearance Learning for Robust Online Multi-Object Tracking.

    Science.gov (United States)

    Bae, Seung-Hwan; Yoon, Kuk-Jin

    2018-03-01

    Online multi-object tracking aims at estimating the tracks of multiple objects instantly with each incoming frame and the information provided up to the moment. It still remains a difficult problem in complex scenes, because of the large ambiguity in associating multiple objects in consecutive frames and the low discriminability between objects appearances. In this paper, we propose a robust online multi-object tracking method that can handle these difficulties effectively. We first define the tracklet confidence using the detectability and continuity of a tracklet, and decompose a multi-object tracking problem into small subproblems based on the tracklet confidence. We then solve the online multi-object tracking problem by associating tracklets and detections in different ways according to their confidence values. Based on this strategy, tracklets sequentially grow with online-provided detections, and fragmented tracklets are linked up with others without any iterative and expensive association steps. For more reliable association between tracklets and detections, we also propose a deep appearance learning method to learn a discriminative appearance model from large training datasets, since the conventional appearance learning methods do not provide rich representation that can distinguish multiple objects with large appearance variations. In addition, we combine online transfer learning for improving appearance discriminability by adapting the pre-trained deep model during online tracking. Experiments with challenging public datasets show distinct performance improvement over other state-of-the-arts batch and online tracking methods, and prove the effect and usefulness of the proposed methods for online multi-object tracking.

  19. Learning from the learning curve: factors associated with successful endoscopic correction of vesicoureteral reflux using dextranomer/hyaluronic acid copolymer.

    Science.gov (United States)

    Dave, Sumit; Lorenzo, Armando J; Khoury, Antoine E; Braga, Luis H P; Skeldon, Sean J; Suoub, Mohammed; Farhat, Walid; Pippi Salle, João L; Bägli, Darius J

    2008-10-01

    Conflicting reports exist regarding the parameters guiding successful correction of vesicoureteral reflux using dextranomer/hyaluronic acid copolymer. We performed logistic regression analysis to evaluate the effect of injected volume while adjusting for other factors potentially associated with success following dextranomer/hyaluronic acid copolymer injection. Between July 2003 and June 2006, 126 consecutive patients (34 boys and 92 girls) with a mean +/- SD age of 6.5 +/- 3.7 years with primary vesicoureteral reflux (196 refluxing ureters) underwent injection for febrile urinary tract infections. Success was defined as complete reflux resolution. Age, gender, laterality, preoperative vesicoureteral reflux grade, surgeon experience, dextranomer/hyaluronic acid copolymer volume, time to surgery from initial presentation and preoperative treatment for lower urinary tract symptoms were analyzed. Vesicoureteral reflux grade was I to V in 7 (3.5%), 53 (27%), 91 (46.4%), 30 (15.3%) and 15 renal units (7.6%), respectively. The success rate after 1 injection was 50% by patient and 59.2% by ureter. Mean injected volume was 0.9 +/- 0.27 ml in those who had a successful injection vs 0.67 +/- 0.24 ml in those in whom injection failed (p hyaluronic acid copolymer compared to 31.7% with less than 0.8 ml. Multivariate analysis confirmed that higher dextranomer/hyaluronic acid copolymer volume (p = 0.001), lower preoperative grade (p = 0.013), surgeon experience (p = 0.025) and treatment for lower urinary tract symptoms (p = 0.009) were associated with successful correction of vesicoureteral reflux. Our analysis strengthens the previously reported association of surgeon experience and vesicoureteral reflux grade with successful endoscopic vesicoureteral reflux correction. The data also revealed an association between injected volume and vesicoureteral reflux correction even while controlling for other variables, highlighting its importance as a true success modifier.

  20. Elevation of Non-Classical (CD14+/lowCD16++) Monocytes Is Associated with Increased Albuminuria and Urine TGF-β1 in HIV-Infected Individuals on Stable Antiretroviral Therapy.

    Science.gov (United States)

    Mitchell, Brooks I; Byron, Mary Margaret; Ng, Roland C; Chow, Dominic C; Ndhlovu, Lishomwa C; Shikuma, Cecilia M

    2016-01-01

    High rates of albuminuria are observed among HIV-infected individuals on stable antiretroviral therapy (ART). Though pro-inflammatory and pro-fibrotic responses are described as components of albuminuria in the general population, it is unclear how these responses are associated to albuminuria in ART-treated chronic HIV. We investigated the relationship of monocyte subsets and urine inflammatory and fibrotic biomarkers to albuminuria in ART-treated HIV-infected participants. Cross-sectional analyses were performed on Hawaii Aging with HIV-cardiovascular disease study cohort participants who were required at entry to be ≥40 years old and on ART ≥3 months. Monocyte subpopulations were determined in banked peripheral blood mononuclear cells (PBMC) using multi-parametric flow-cytometry. Entry random urine samples were assessed for albumin-to-creatinine ratios (UACR). Urine samples were measured for inflammatory and fibrotic biomarkers using Luminex technology. Among 96 HIV-infected subjects with measured UACR (87% male, 59% Caucasian, and 89% undetectable HIV RNA with median CD4 of 495.5 cells/μL), 18 patients (19%) had albuminuria. Non-classical (CD14low/+CD16++) monocytes were significantly elevated in subjects with albuminuria (p = 0.034) and were correlated to UACR (r = 0.238, p = 0.019). Elevated non-classical monocyte counts were significant predictors of worsening albuminuria, independent of traditional- and ART-associated risk factors (β = 0.539, p = 0.007). Urine TGF-β1 and collagen-IV were significantly higher in albuminuric compared to non-albuminuric participants (TGF-β1; p = 0.039 and collagen-IV; p = 0.042). Urine TGF-β1 was significantly correlated with non-classical monocyte counts (r = 0.464, p = 0.017). Alterations in monocyte subpopulations and urine pro-fibrotic factors may play a role in kidney dysfunction during chronic HIV infection and warrants further study.

  1. Active sensing associated with spatial learning reveals memory-based attention in an electric fish.

    Science.gov (United States)

    Jun, James J; Longtin, André; Maler, Leonard

    2016-05-01

    Active sensing behaviors reveal what an animal is attending to and how it changes with learning. Gymnotus sp, a gymnotiform weakly electric fish, generates an electric organ discharge (EOD) as discrete pulses to actively sense its surroundings. We monitored freely behaving gymnotid fish in a large dark "maze" and extracted their trajectories and EOD pulse pattern and rate while they learned to find food with electrically detectable landmarks as cues. After training, they more rapidly found food using shorter, more stereotyped trajectories and spent more time near the food location. We observed three forms of active sensing: sustained high EOD rates per unit distance (sampling density), transient large increases in EOD rate (E-scans) and stereotyped scanning movements (B-scans) were initially strong at landmarks and food, but, after learning, intensified only at the food location. During probe (no food) trials, after learning, the fish's search area and intense active sampling was still centered on the missing food location, but now also increased near landmarks. We hypothesize that active sensing is a behavioral manifestation of attention and essential for spatial learning; the fish use spatial memory of landmarks and path integration to reach the expected food location and confine their attention to this region. Copyright © 2016 the American Physiological Society.

  2. Deletion of PEA-15 in mice is associated with specific impairments of spatial learning abilities

    Directory of Open Access Journals (Sweden)

    Hale Gregory

    2009-11-01

    Full Text Available Abstract Background PEA-15 is a phosphoprotein that binds and regulates ERK MAP kinase and RSK2 and is highly expressed throughout the brain. PEA-15 alters c-Fos and CREB-mediated transcription as a result of these interactions. To determine if PEA-15 contributes to the function of the nervous system we tested mice lacking PEA-15 in a series of experiments designed to measure learning, sensory/motor function, and stress reactivity. Results We report that PEA-15 null mice exhibited impaired learning in three distinct spatial tasks, while they exhibited normal fear conditioning, passive avoidance, egocentric navigation, and odor discrimination. PEA-15 null mice also had deficient forepaw strength and in limited instances, heightened stress reactivity and/or anxiety. However, these non-cognitive variables did not appear to account for the observed spatial learning impairments. The null mice maintained normal weight, pain sensitivity, and coordination when compared to wild type controls. Conclusion We found that PEA-15 null mice have spatial learning disabilities that are similar to those of mice where ERK or RSK2 function is impaired. We suggest PEA-15 may be an essential regulator of ERK-dependent spatial learning.

  3. Motor learning in healthy humans is associated to gray matter changes: a tensor-based morphometry study.

    Science.gov (United States)

    Filippi, Massimo; Ceccarelli, Antonia; Pagani, Elisabetta; Gatti, Roberto; Rossi, Alice; Stefanelli, Laura; Falini, Andrea; Comi, Giancarlo; Rocca, Maria Assunta

    2010-04-15

    We used tensor-based morphometry (TBM) to: 1) map gray matter (GM) volume changes associated with motor learning in young healthy individuals; 2) evaluate if GM changes persist three months after cessation of motor training; and 3) assess whether the use of different schemes of motor training during the learning phase could lead to volume modifications of specific GM structures. From 31 healthy subjects, motor functional assessment and brain 3D T1-weighted sequence were obtained: before motor training (time 0), at the end of training (two weeks) (time 2), and three months later (time 3). Fifteen subjects (group A) were trained with goal-directed motor sequences, and 16 (group B) with non purposeful motor actions of the right hand. At time 1 vs. time 0, the whole sample of subjects had GM volume increase in regions of the temporo-occipital lobes, inferior parietal lobule (IPL) and middle frontal gyrus, while at time 2 vs. time 1, an increased GM volume in the middle temporal gyrus was seen. At time 1 vs. time 0, compared to group B, group A had a GM volume increase of the hippocampi, while the opposite comparison showed greater GM volume increase in the IPL and insula in group B vs. group A. Motor learning results in structural GM changes of different brain areas which are part of specific neuronal networks and tend to persist after training is stopped. The scheme applied during the learning phase influences the pattern of such structural changes.

  4. Cognitive learning is associated with gray matter changes in healthy human individuals: a tensor-based morphometry study.

    Science.gov (United States)

    Ceccarelli, Antonia; Rocca, Maria Assunta; Pagani, Elisabetta; Falini, Andrea; Comi, Giancarlo; Filippi, Massimo

    2009-11-15

    Longitudinal voxel-based morphometry studies have demonstrated morphological changes in cortical structures following motor and cognitive learning. In this study, we applied, for the first time, tensor-based morphometry (TBM) to assess the short-term structural brain gray matter (GM) changes associated with cognitive learning in healthy subjects. Using a 3 T scanner, a 3D T1-weighted sequence was acquired from 32 students at baseline and after two weeks. Students were separated into two groups: 13 defined as "students in cognitive training", who underwent a two-week cognitive learning period, and 19 "students not in cognitive training", who were not involved in any teaching activity. GM changes were assessed using TBM and statistical parametric mapping. Baseline regional GM volume did not differ between the two groups. At follow up, compared to "students not in cognitive training", the "students in cognitive training" had a significant GM volume increase in the dorsomedial frontal cortex, the orbitofrontal cortex, and the precuneus (p<0.001). These results suggest that cognitive learning results in short-term structural GM changes of neuronal networks of the human brain, which are known to be involved in cognition. This may have important implications for the development of rehabilitation strategies in patients with neurological diseases.

  5. Motor learning in healthy humans is associated to gray matter changes: a tensor-based morphometry study.

    Directory of Open Access Journals (Sweden)

    Massimo Filippi

    Full Text Available We used tensor-based morphometry (TBM to: 1 map gray matter (GM volume changes associated with motor learning in young healthy individuals; 2 evaluate if GM changes persist three months after cessation of motor training; and 3 assess whether the use of different schemes of motor training during the learning phase could lead to volume modifications of specific GM structures. From 31 healthy subjects, motor functional assessment and brain 3D T1-weighted sequence were obtained: before motor training (time 0, at the end of training (two weeks (time 2, and three months later (time 3. Fifteen subjects (group A were trained with goal-directed motor sequences, and 16 (group B with non purposeful motor actions of the right hand. At time 1 vs. time 0, the whole sample of subjects had GM volume increase in regions of the temporo-occipital lobes, inferior parietal lobule (IPL and middle frontal gyrus, while at time 2 vs. time 1, an increased GM volume in the middle temporal gyrus was seen. At time 1 vs. time 0, compared to group B, group A had a GM volume increase of the hippocampi, while the opposite comparison showed greater GM volume increase in the IPL and insula in group B vs. group A. Motor learning results in structural GM changes of different brain areas which are part of specific neuronal networks and tend to persist after training is stopped. The scheme applied during the learning phase influences the pattern of such structural changes.

  6. Effects of enriched physical and social environments on motor performance, associative learning, and hippocampal neurogenesis in mice.

    Directory of Open Access Journals (Sweden)

    Noelia Madroñal

    2010-06-01

    Full Text Available We have studied the motor abilities and associative learning capabilities of adult mice placed in different enriched environments. Three-month-old animals were maintained for a month alone (AL, alone in a physically enriched environment (PHY, and, finally, in groups in the absence (SO or presence (SOPHY of an enriched environment. The animals' capabilities were subsequently checked in the rotarod test, and for classical and instrumental learning. The PHY and SOPHY groups presented better performances in the rotarod test and in the acquisition of the instrumental learning task. In contrast, no significant differences between groups were observed for classical eyeblink conditioning. The four groups presented similar increases in the strength of field EPSPs (fEPSPs evoked at the hippocampal CA3-CA1 synapse across classical conditioning sessions, with no significant differences between groups. These trained animals were pulse-injected with bromodeoxyuridine (BrdU to determine hippocampal neurogenesis. No significant differences were found in the number of NeuN/BrdU double-labeled neurons. We repeated the same BrdU study in one-month-old mice raised for an additional month in the above-mentioned four different environments. These animals were not submitted to rotarod or conditioned tests. Non-trained PHY and SOPHY groups presented more neurogenesis than the other two groups. Thus, neurogenesis seems to be related to physical enrichment at early ages, but not to learning acquisition in adult mice.

  7. The Transfer of Learning Associated with Audio Feedback on Written Work

    Directory of Open Access Journals (Sweden)

    Tanya Martini

    2014-11-01

    Full Text Available This study examined whether audio feedback provided to undergraduates (N=51 about one paper would prove beneficial in terms of improving their grades on another, unrelated paper of the same type. We examined this issue both in terms of student beliefs about learning transfer, as well as their actual ability to transfer what had been learned on one assignment to another, subsequent assignment. Results indicated that students believed that they would be able to transfer what they had learned via audio feedback. Moreover, results also suggested that students actually did generalize the overarching comments about content and structure made in the audio files to a subsequent paper, the content of which differed substantially from the initial one. Both students and teaching assistants demonstrated very favourable responses to this type of feedback, suggesting that it was both clear and comprehensive.

  8. Paired associate learning of Morse code and Braille letter names by dyslexic and normal children.

    Science.gov (United States)

    Rudel, R G; Denckla, M B; Spalten, E

    1976-03-01

    Twenty dyslexic and twenty normal children, matched for age and sex and with the same mean I.Q. were tested on their ability to learn letter names of Braille configurations presented visually or tactually and to Morse Code signals presented aurally. The dyslexic Ss learned fewer letters in all three modalities although for both groups the visual-verbal method was easiest. The deficits were not attributable to specific modality dysfunction nor to a failure of intersensory integration. More general encoding and retrieval difficulties appear to be implicated.

  9. Proceedings of the International Association for Development of the Information Society (IADIS) International Conference on e-Learning (Madeira, Portugal, July 1-4, 2016)

    Science.gov (United States)

    Nunes, Miguel Baptista, Ed.; McPherson, Maggie, Ed.

    2016-01-01

    These proceedings contain the papers of the International Conference e-Learning 2016, which was organised by the International Association for Development of the Information Society, 1-3 July, 2016. This conference is part of the Multi Conference on Computer Science and Information Systems 2016, 1-4 July. The e-Learning (EL) 2016 conference aims…

  10. Proceedings of the International Association for Development of the Information Society (IADIS) International Conference on Mobile Learning (12th, Vilamoura, Algarve, Portugal, April 9-11, 2016)

    Science.gov (United States)

    Sánchez, Inmaculada Arnedillo, Ed.; Isaías, Pedro, Ed.

    2016-01-01

    These proceedings contain the papers of the 12th International Conference on Mobile Learning 2016, which was organized by the International Association for Development of the Information Society, in Vilamoura, Algarve, Portugal, April 9-11, 2016. The Mobile Learning 2016 Conference seeks to provide a forum for the presentation and discussion of…

  11. Proceedings of the International Association for Development of the Information Society (IADIS) International Conference on Mobile Learning (Lisbon, Portugal, March 14-16, 2013)

    Science.gov (United States)

    Sánchez, Inmaculada Arnedillo, Ed.; Isaías, Pedro, Ed.

    2013-01-01

    These proceedings contain the papers of the International Conference on Mobile Learning 2013, which was organised by the International Association for Development of the Information Society, in Lisbon, Portugal, March 14-16, 2013. The Mobile Learning 2013 International Conference seeks to provide a forum for the presentation and discussion of…

  12. Proceedings of the International Association for Development of the Information Society (IADIS) International Conference on e-Learning (Prague, Czech Republic, July 23-26, 2013)

    Science.gov (United States)

    Nunes, Miguel Baptista, Ed.; McPherson, Maggie, Ed.

    2013-01-01

    These proceedings contain the papers of the International Conference e-Learning 2013, which was organised by the International Association for Development of the Information Society and is part of the Multi Conference on Computer Science and Information Systems (Prague, Czech Republic, July 23-26, 2013). The e-Learning 2013 conference aims to…

  13. Proceedings of the International Association for Development of the Information Society (IADIS) International Conference on Mobile Learning (11th, Madeira, Portugal, March 14-16, 2015)

    Science.gov (United States)

    Sánchez, Inmaculada Arnedillo, Ed.; Isaías, Pedro, Ed.

    2015-01-01

    These proceedings contain the papers and posters of the 11th International Conference on Mobile Learning 2015, which was organised by the International Association for Development of the Information Society, in Madeira, Portugal, March 14-16, 2015. The Mobile Learning 2015 Conferen