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Learning Abilities (learning + ability)

Distribution by Scientific Domains

Life Sciences	36%
Medical Sciences	30%
Psychology	19%
4 Other Domains	15%

Selected Abstracts

LEARNING ABILITY AND LONGEVITY: A SYMMETRICAL EVOLUTIONARY TRADE-OFF IN DROSOPHILA

EVOLUTION, Issue 6 2008
Joep M. S. Burger
Learning ability can be substantially improved by artificial selection in animals ranging from Drosophila to rats. Thus these species have not used their evolutionary potential with respect to learning ability, despite intuitively expected and experimentally demonstrated adaptive advantages of learning. This suggests that learning is costly, but this notion has rarely been tested. Here we report correlated responses of life-history traits to selection for improved learning in Drosophila melanogaster. Replicate populations selected for improved learning lived on average 15% shorter than the corresponding unselected control populations. They also showed a minor reduction in fecundity late in life and possibly a minor increase in dry adult mass. Selection for improved learning had no effect on egg-to-adult viability, development rate, or desiccation resistance. Because shortened longevity was the strongest correlated response to selection for improved learning, we also measured learning ability in another set of replicate populations that had been selected for extended longevity. In a classical olfactory conditioning assay, these long-lived flies showed an almost 40% reduction in learning ability early in life. This effect disappeared with age. Our results suggest a symmetrical evolutionary trade-off between learning ability and longevity in Drosophila. [source]

The Assessment of Basic Learning Abilities Test for Persons with Intellectual Disability: A Valuable Clinical Tool

JOURNAL OF APPLIED RESEARCH IN INTELLECTUAL DISABILITIES, Issue 5 2007
Tricia Vause
The Assessment of Basic Learning Abilities (ABLA) test requires a tester to attempt to teach to a person, using standard prompting and reinforcement procedures, six tasks that are hierarchically ordered in difficulty. Performance on the test provides valuable information for teachers and rehabilitation workers to match the difficulty of training tasks with the learning ability of persons with profound, severe and moderate intellectual disabilities. This paper summarizes the characteristics of the test, outlines the testing procedures, and reviews supporting data and practical guidelines for clinicians. [source]

A Post-ischaemic Single Administration of Galanthamine, a Cholinesterase Inhibitor, Improves Learning Ability in Rats

JOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 9 2000
A. I. ILIEV
Transient forebrain ischaemia is widely observed in clinical practice. We have examined the effect of a single administration of the Cholinesterase inhibitor galanthamine (2 mgkg,1, i.p.) 25 min after reperfusion in male Sprague-Dawley rats (180 ± 20 g) after a 20-min common carotid artery occlusion. Twenty-four-hours post-ischaemia there was no difference in motor co-ordination or muscle tonus of the rats treated with or without galanthamine as assessed by the rota-rod test. Learning ability was examined using the shuttle-box test, evaluating the latency time and the number of errors for six days in succession. The performance of the ischaemic saline-injected rats was significantly impaired on days 4, 5, 6 (latency time) compared with the non-ischaemic rats and with the ischaemic animals administered galanthamine (P< 0.05). Similar results were obtained when counting the number of errors (failure to cross the cage during conditioned or unconditioned stimulus). The monitoring of body temperature during the first 12-h post-ischaemia did not show any significant difference between the groups. The data showed a beneficial effect of galanthamine on the recovery of learning ability when administered once only post-ischaemia. This suggests a direct effect on the early pathologic mechanisms of CNS damage. Cholinesterase inhibitors may prove useful in the early clinical treatment of ischaemic conditions. [source]

LEARNING ABILITY AND LONGEVITY: A SYMMETRICAL EVOLUTIONARY TRADE-OFF IN DROSOPHILA

A Post-ischaemic Single Administration of Galanthamine, a Cholinesterase Inhibitor, Improves Learning Ability in Rats

Daily ingestion of green tea catechins from adulthood suppressed brain dysfunction in aged mice

BIOFACTORS, Issue 4 2008
Keiko Unno
Abstract Oxidative damage is believed to be an important cause of senescence. We have previously found that green tea catechins (GT-catechin), potent antioxidants, decrease oxidative damage to DNA and suppress brain dysfunction in aged senescence-accelerated mice (SAMP10) when ingested from the age of 1 month to the age of 12 months. To clarify the effect of GT-catechin on suppression of brain senescence, we investigated the effect of starting period to ingest GT-catechin. Six- or 9-month-old SAMP10 mice were allowed free access to water containing 0.02% GT-catechin. SAMP10 mice exhibit senescence characteristics such as shortened life span, atrophied forebrain and lowered learning and memory abilities. Learning ability was significantly higher in mice that ingested GT-catechin from the age of 6 months to 12 months when compared with same-aged control mice drank water without GT-catechin. Starting GT-catechin intake from the age of 9 months tended to improve learning ability. The ages of 6 and 9 months are thought to be adult and middle ages, respectively in SAMP10 mice. This result suggested that GT-catechin was helpful in suppressing brain dysfunction with aging even when ingestion started at the adult age. [source]

Increase of learning abilities and maturation of the vertical lobe complex during postembryonic development in the cuttlefish, Sepia

DEVELOPMENTAL PSYCHOBIOLOGY, Issue 2 2001
Ludovic Dickel
Abstract When shown prawns in a glass tube, cuttlefish quickly learn to inhibit their predatory behavior. By using a visual learning paradigm, we studied training and retention performances of cuttlefish aged from 8 to 90 days. We found an improvement in the acquisition of learning abilities during the first 2 months of life as well as an increase of 24-hr retention performance between 30 and 90 days of age. Using morphometric measurements of different lobes of the central nervous system, we correlated the emergence of these learning abilities with the postembryonic development of related nervous structures. Our results show that only the growth of the superior frontal and vertical lobes appears to be significantly correlated with the improvement of learning and long-term retention performances. Thus, as found in earlier data collected in Octopus, the vertical lobe complex of the cuttlefish seems to be involved in these learning processes. © 2001 John Wiley & Sons, Inc. Dev Psychobiol 40: 92,98, 2001 [source]

Changes in individual and group spatial and verbal learning characteristics after anterior temporal lobectomy

EPILEPSIA, Issue 6 2009
Mario F. Dulay
Summary Purpose:, To evaluate the effects of anterior temporal lobectomy (ATL) on individual and group spatial and verbal learning and memory abilities as a function of side of surgery and seizure control outcome. Methods:, We evaluated pre- and postsurgical learning and memory abilities of 75 left-hemisphere language dominant individuals who underwent ATL (33 left, 42 right) using the 8-trial Nonverbal Selective Reminding test and the 12-trial Verbal Selective Reminding test. Results:, Reliable change index methods indicated that 40.5% of individuals who underwent right-ATL had a clinically significant decline in spatial memory, and 62.5% of individuals who underwent left-ATL had a significant reduction in verbal memory. Growth curve analyses indicated that both side of surgery and poor seizure outcome independently affected the learning slope in the best fitting models. Left-ATL reduced the slope, but did not affect the overall shape, of verbal learning across trials. On the other hand, poor seizure control outcome affected the slope of spatial learning regardless of the side of surgery. Discussion:, Results demonstrate both individual and group declines in spatial memory and learning after ATL. Results suggest that individuals who undergo right-ATL should be counseled regarding the likelihood of a decline in spatial memory and learning abilities after ATL. Results also suggest that individuals with poor seizure control after ATL should be referred for rehabilitation services given the significant declines in spatial and verbal memory that occurred in our sample regardless of side of surgery. [source]

Empirical tests of the functional significance of amygdala-based modulation of hippocampal representations: evidence for multiple memory consolidation pathways

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 5 2007
Robert J. McDonald
Abstract This series of experiments evaluated the effects of amygdala damage on the acquisition and long-term retention of variants of the water task, and tested the hypothesis that the amygdala is an essential neural system for consolidation of hippocampal memories. In Experiment 1, rats with large, neurotoxic lesions of the amygdala (AMYG) showed normal acquisition on the standard spatial version of the water task, as well as normal retention and decay rate profiles on the 24-h and 30-day retention probes. In Experiment 2, AMYG rats showed normal one-trial place learning abilities and could retain this one-trial information over a 24 h delay. Experiment 3 showed that the amygdala lesions used in this study were functionally significant because AMYG rats, from Experiment 2, showed impairments in a discriminative fear conditioning to context paradigm. Experiment 4 was a critical test of the idea that the amygdala is a decisive locus for consolidation of hippocampal memories. AMYG rats were trained to sub-asymptotic levels of performance on the standard version of the water task. Following each training session, the subjects were given a post-training peripheral injection of d -amphetamine. A probe test revealed that normal subjects and AMYG rats showed similar post-training memory improvement effects. Taken together, the results show that hippocampal memory consolidation processes do not require amygdala modulation. Arguments for an alternative view are presented suggesting that there are multiple memory consolidation pathways, one of which may depend on amygdala neural circuitry. [source]

Dissociation of function between the dorsal and the ventral hippocampus in spatial learning abilities of the rat: a within-subject, within-task comparison of reference and working spatial memory

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 3 2004
Helen H. J. Pothuizen
Abstract Lesions restricted to the dorsal, but not the ventral, hippocampus severely impair the formation of spatial memory. This dissociation was first demonstrated using the water maze task. The present study investigated whether the dorsal and the ventral hippocampus are involved differentially in spatial reference and spatial working memory using a four-baited/four-unbaited version of the eight-arm radial maze task. This test allows the concurrent evaluation of reference and working memory with respect to the same set of spatial cues, and thereby enables a within-subjects within-task comparison between the two forms of memory functions. Rats with N -methyl- d -aspartic acid-induced excitotoxic lesions of the dorsal hippocampus, ventral hippocampus or both were compared with sham and unoperated controls. We showed that dorsal lesions were as effective as complete lesions in severely disrupting both reference and working spatial memory, whereas rats with ventral lesions performed at a level comparable with controls. These results lend further support to the existence of a functional dissociation between the dorsal and the ventral hippocampus, with the former being preferentially involved in spatial learning. [source]

EVOLUTION OF REPRODUCTIVE STRATEGIES IN THE SEXUALLY DECEPTIVE ORCHID OPHRYS SPHEGODES: HOW DOES FLOWER-SPECIFIC VARIATION OF ODOR SIGNALS INFLUENCE REPRODUCTIVE SUCCESS?

EVOLUTION, Issue 6 2000
Manfred Ayasse
Abstract The orchid Ophrys sphegodes Miller is pollinated by sexually excited males of the solitary bee Andrena nigroaenea, which are lured to the flowers by visual cues and volatile semiochemicals. In O. sphegodes, visits by pollinators are rare. Because of this low frequency of pollination, one would expect the evolution of strategies that increase the chance that males will visit more than one flower on the same plant; this would increase the number of pollination events on a plant and therefore the number of seeds produced. Using gas chromatography-mass spectrometry (GC-MS) analyses, we identified more than 100 compounds in the odor bouquets of labellum extracts from O. sphegodes; 24 compounds were found to be biologically active in male olfactory receptors based on gas chromatography with electroantennographic detection (GC-EAD). Gas chromatography (GC) analyses of odors from individual flowers showed less intraspecific variation in the odor bouquets of the biologically active compounds as compared to nonactive compounds. This can be explained by a higher selective pressure on the pollinator-attracting communication signal. Furthermore, we found a characteristic variation in the GC-EAD active esters and aldehydes among flowers of different stem positions within an inflorescence and in the n-alkanes and n-alkenes among plants from different populations. In our behavioral field tests, we showed that male bees learn the odor bouquets of individual flowers during mating attempts and recognize them in later encounters. Bees thereby avoid trying to mate with flowers they have visited previously, but do not avoid other flowers either of a different or the same plant. By varying the relative proportions of saturated esters and aldehydes between flowers of different stem positions, we demonstrated that a plant may take advantage of the learning abilities of the pollinators and influence flower visitation behavior. Sixty-seven percent of the males that visited one flower in an inflorescence returned to visit a second flower of the same inflorescence. However, geitonogamy is prevented and the likelihood of cross-fertilization is enhanced by the time required for the pollinium deposited on the pollinator to complete its bending movement, which is necessary for pollination to occur. Cross-fertilization is furthermore enhanced by the high degree of odor variation between plants. This variation minimizes learned avoidance of the flowers and increases the likelihood that a given pollinator would visit several to many different plants within a population. [source]

Neuronal cell adhesion molecule deletion induces a cognitive and behavioral phenotype reflective of impulsivity

GENES, BRAIN AND BEHAVIOR, Issue 4 2008
L. D. Matzel
Cell adhesion molecules, such as neuronal cell adhesion molecule (Nr-CAM), mediate cell,cell interactions in both the developing and mature nervous system. Neuronal cell adhesion molecule is believed to play a critical role in cell adhesion and migration, axonal growth, guidance, target recognition and synapse formation. Here, wild-type, heterozygous and Nr-CAM null mice were assessed on a battery of five learning tasks (Lashley maze, odor discrimination, passive avoidance, spatial water maze and fear conditioning) previously developed to characterize the general learning abilities of laboratory mice. Additionally, all animals were tested on 10 measures of sensory/motor function, emotionality and stress reactivity. We report that the Nr-CAM deletion had no impact on four of the learning tasks (fear conditioning, spatial water maze, Lashley maze and odor discrimination). However, Nr-CAM null mice exhibited impaired performance on a task that required animals to suppress movement (passive avoidance). Although Nr-CAM mutants expressed normal levels of general activity and body weights, they did exhibit an increased propensity to enter stressful areas of novel environments (the center of an open field and the lighted side of a dark/light box), exhibited higher sensitivity to pain (hot plate) and were more sensitive to the aversive effects of foot shock (shock-induced freezing). This behavioral phenotype suggests that Nr-CAM does not play a central role in the regulation of general cognitive abilities but may have a critical function in regulating impulsivity and possibly an animal's susceptibility to drug abuse and addiction. [source]

Fuzzy logic-based networks: A study in logic data interpretation

INTERNATIONAL JOURNAL OF INTELLIGENT SYSTEMS, Issue 12 2006
Xiaofeng Liang
Fuzzy neurons may have outstanding learning abilities and are endowed with significant interpretation capabilities. In this study, we are concerned with the development of logic networks composed of fuzzy neurons. The main phase of the design includes the granulation of the output space (via triangular fuzzy sets) being realized with the use of fuzzy equalization. In the sequel these fuzzy sets are used to guide the construction of a family of fuzzy sets in the input space. Further processing of the resulting fuzzy sets deals with some additional aggregation of those that are not sufficiently distinct. This helps reduce the size of the logic network. We include comprehensive experimentation and offer a thorough interpretation of the networks. Experiments concerning real-world continuous data help evaluate the network's appealing properties: transparent interpretability and practical feasibility. © 2006 Wiley Periodicals, Inc. Int J Int Syst 21: 1249,1267, 2006. [source]

Critical thinking and learning styles of students in conventional and accelerated programmes

INTERNATIONAL NURSING REVIEW, Issue 1 2006
W. A. Suliman rn
Aim and purpose:, To assess the difference between the predominant critical thinking disposition(s) and learning styles of nursing students in the conventional (Stream I) and the accelerated (Stream II) baccalaureate nursing education programmes. This study will be beneficial to students, faculty and institutions as it will help them to acquire better understanding of critical thinking potentials and learning styles of nurses, as well as the relationship between learning styles and critical thinking dispositions. Method:, This was a descriptive correlational study. The convenience sample consisted of 80 Stream I and 50 Stream II students. The following instruments were used for data collection: The Learning Styles Inventory of Kolb and the California Critical Thinking Dispositions Inventory of Facione and Facione. Descriptive and inferential statistics were used to analyse the data. Results:, Overall, Stream II students were significantly more critical thinkers (P = 0.000), inquisitive (P = 0.000) and self-confident (P = 0.002). The predominant learning styles of Streams I and II were the diverger and the converger, respectively, with no difference except in relation to their learning abilities, namely, concrete experience (P = 0.017), in favour of Stream I. Further, the findings indicate a weak (range of r = 0.209,0.328) though significant (range of P = 0.017,0.000) correlation between learning abilities and various critical thinking dispositions. [source]

Apolipoprotein D is involved in the mechanisms regulating protection from oxidative stress

AGING CELL, Issue 4 2008
Maria D. Ganfornina
Summary Many nervous system pathologies are associated with increased levels of apolipoprotein D (ApoD), a lipocalin also expressed during normal development and aging. An ApoD homologous gene in Drosophila, Glial Lazarillo, regulates resistance to stress, and neurodegeneration in the aging brain. Here we study for the first time the protective potential of ApoD in a vertebrate model organism. Loss of mouse ApoD function increases the sensitivity to oxidative stress and the levels of brain lipid peroxidation, and impairs locomotor and learning abilities. Human ApoD overexpression in the mouse brain produces opposite effects, increasing survival and preventing the raise of brain lipid peroxides after oxidant treatment. These observations, together with its transcriptional up-regulation in the brain upon oxidative insult, identify ApoD as an acute response protein with a protective and therefore beneficial function mediated by the control of peroxidated lipids. [source]

Why there is better evidence for culture in fish than chimpanzees

JOURNAL OF FISH BIOLOGY, Issue 2003
K. N. Laland
Fish have comparatively small brains and are not renowned for their intelligence. Yet a series of laboratory experiments on the guppy reveals that they can be surprisingly good at learning from each other, and that social learning processes can mediate behavioural traditions analogous to the tool using traditions of different populations of chimpanzees. Transmission chain experiments have established that arbitrary and even maladaptive information can be socially transmitted among shoals of fish. Studies of behavioural innovation in guppies are strikingly consistent with findings of equivalent studies in primates. There are strong sex differences in innovatory tendencies and social learning abilities in guppies, which also parallel observations of primates. These studies suggest that the adage ,necessity is the mother of invention' may be a characteristic feature of animal innovation. When considered in combination with the findings of transfer experiments carried out on natural populations of fish, it becomes apparent that fish are an excellent model system for studies of animal social learning and culture. [source]

Implicit memory is independent from IQ and age but not from etiology: evidence from Down and Williams syndromes

JOURNAL OF INTELLECTUAL DISABILITY RESEARCH, Issue 12 2007
S. Vicari
Abstract Background In the last few years, experimental data have been reported on differences in implicit memory processes of genetically distinct groups of individuals with Intellectual Disability (ID). These evidences are relevant for the more general debate on supposed asynchrony of cognitive maturation in children with abnormal brain development. This study, comparing implicit memory processes in individuals with Williams syndrome (WS) and Down syndrome (DS), was planned to verify the ,etiological specificity' hypotheses pertaining to the skill learning abilities of individuals with ID. Method A modified version of Nissen and Bullemer's (1987) Serial Reaction Time (SRT) task was used. The performances of three group were evaluated. The first group consisted of thirty-two people with WS (18 males and 14 females). The second group was comprised of twenty-six individuals with DS (14 males and 12 females). The two groups of individuals with ID were selected so that the groups were comparable as for mental age and chronological age. The third group consisted of forty-nine typically developed children with a mental age similar to that of the groups with WS and DS. Results The two groups of individuals with ID demonstrated different patterns of procedural learning. WS individuals revealed poor implicit learning of the temporal sequence of events characterizing the ordered blocks in the SRT task. Indeed, differently from normal controls, WS participants showed no reaction time (RT) speeding through ordered blocks. Most importantly, the rebound effect, which so dramatically affected normal children's RTs passing from the last ordered to the last block, had only a marginal influence on WS children's RTs. Differently from the WS group, the rate of procedural learning of the participants with DS was comparable to that of their controls. Indeed, DS and typically developed individuals showed parallel RT variations in the series of ordered blocks and, more importantly, passing from the last ordered to the last block. Therefore, a substantial preservation of skill learning abilities in this genetic syndrome is confirmed. Conclusions The results of the present study document that procedural learning in individuals with ID depends on the aetiology of the syndrome, thus supporting the etiological specificity account of their cognitive development. These results are relevant for our knowledge about the qualitative aspects and the underlying neurobiological substrate of the anomalous cognitive development in mentally retarded people. [source]

Genuine Episodic Memory Deficits and Executive Dysfunctions in Alcoholic Subjects Early in Abstinence

ALCOHOLISM, Issue 7 2007
Anne Lise Pitel
Background: Chronic alcoholism is known to impair episodic memory function, but the specific nature of this impairment is still unclear. Moreover, it has never been established whether episodic memory deficit in alcoholism is an intrinsic memory deficit or whether it has an executive origin. Thus, the objectives are to specify which episodic memory processes are impaired early in abstinence from alcohol and to determine whether they should be regarded as genuine memory deficits or rather as the indirect consequences of executive impairments. Methods: Forty recently detoxified alcoholic inpatients at alcohol entry treatment and 55 group-matched controls underwent a neuropsychological assessment of episodic memory and executive functions. The episodic memory evaluation consisted of 3 tasks complementing each other designed to measure the different episodic memory components (learning, storage, encoding and retrieval, contextual memory, and autonoetic consciousness) and 5 executive tasks testing capacities of organization, inhibition, flexibility, updating, and integration. Results: Compared with control subjects, alcoholic patients presented impaired learning abilities, encoding processes, retrieval processes, contextual memory and autonoetic consciousness. However, there was no difference between the 2 groups regarding the storage capacities assessed by the rate of forgetting. Concerning executive functions, alcoholic subjects displayed deficits in each executive task used. Nevertheless, stepwise regression analyses showed that only performances on fluency tasks were significantly predictive of some of the episodic memory disorders (learning abilities for 40%, encoding processes for 20%, temporal memory for 21%, and state of consciousness associated with memories for 26%) in the alcoholic group. Discussion: At alcohol treatment entry, alcoholic patients present genuine episodic memory deficits that cannot be regarded solely as the consequences of executive dysfunctions. These results are in accordance with neuroimaging findings showing hippocampal atrophy. Moreover, given the involvement of episodic memory and executive functions in alcohol treatment, these data could have clinical implications. [source]

Generalist Genes: Genetic Links Between Brain, Mind, and Education

MIND, BRAIN, AND EDUCATION, Issue 1 2007
Robert Plomin
ABSTRACT, Genetics contributes importantly to learning abilities and disabilities,not just to reading, the target of most genetic research, but also to mathematics and other academic areas as well. One of the most important recent findings from quantitative genetic research such as twin studies is that the same set of genes is largely responsible for genetic influence across these domains. We call these "generalist genes" to highlight their pervasive influence. In other words, most genes found to be associated with a particular learning ability or disability (such as reading) will also be associated with other learning abilities and disabilities (such as mathematics). Moreover, some generalist genes for learning abilities and disabilities are even more general in their effect, encompassing other cognitive abilities such as memory and spatial ability. When these generalist genes are identified, they will greatly accelerate research on general mechanisms at all levels of analysis from genes to brain to behavior. [source]

Specific reading disability (dyslexia): what have we learned in the past four decades?

THE JOURNAL OF CHILD PSYCHOLOGY AND PSYCHIATRY AND ALLIED DISCIPLINES, Issue 1 2004
Frank R. Vellutino
We summarize some of the most important findings from research evaluating the hypothesized causes of specific reading disability (,dyslexia') over the past four decades. After outlining components of reading ability, we discuss manifest causes of reading difficulties, in terms of deficiencies in component reading skills that might lead to such difficulties. The evidence suggests that inadequate facility in word identification due, in most cases, to more basic deficits in alphabetic coding is the basic cause of difficulties in learning to read. We next discuss hypothesized deficiencies in reading-related cognitive abilities as underlying causes of deficiencies in component reading skills. The evidence in these areas suggests that, in most cases, phonological skills deficiencies associated with phonological coding deficits are the probable causes of the disorder rather than visual, semantic, or syntactic deficits, although reading difficulties in some children may be associated with general language deficits. Hypothesized deficits in general learning abilities (e.g., attention, association learning, cross-modal transfer etc.) and low-level sensory deficits have weak validity as causal factors in specific reading disability. These inferences are, by and large, supported by research evaluating the biological foundations of dyslexia. Finally, evidence is presented in support of the idea that many poor readers are impaired because of inadequate instruction or other experiential factors. This does not mean that biological factors are not relevant, because the brain and environment interact to produce the neural networks that support reading acquisition. We conclude with a discussion of the clinical implications of the research findings, focusing on the need for enhanced instruction. [source]

Pharmacokinetics of sabeluzole and dextromethorphan oxidation capacity in patients with severe hepatic dysfunction and healthy volunteers

BRITISH JOURNAL OF CLINICAL PHARMACOLOGY, Issue 2 2001
G. P. Pageaux
Aims, The primary objective of this study was to determine how the pharmacokinetics of sabeluzole, an investigational drug with specific effects on memory and learning abilities, are affected by chronic liver disease. Since sabeluzole is metabolised by CYP2D6, a secondary objective was to study the correlation between CYP2D6 activity (as assessed by the dextromethorphan dextrorphan metabolic ratio) and hepatic dysfunction. Methods, The single-dose pharmacokinetics of sabeluzole (10 mg) was compared in 10 healthy Caucasian subjects and 10 patients with severe hepatic dysfunction. The urinary dextromethorphan/dextrorphan (DMP/DRP) metabolic ratio was determined after intake of 20 mg dextromethorphan (NODEX® capsules). Results, The terminal half-life of sabeluzole was significantly prolonged in subjects with severe hepatic dysfunction vs healthy subjects (respectively 39.3 ± 11.5 h; 17.5 ± 10.2 h (mean ±,s.d.)). The areas under the curve (AUC) were significantly higher in subjects with severe hepatic dysfunction than in healthy volunteers (681 ± 200 ng ml ,1h vs 331 ± 282 ng ml ,1h). There was a significant correlation between the AUC(0,,) and the DMP/DRP metabolic ratio in healthy volunteers and subjects with severe hepatic dysfunction. AUC was greater and elimination of sabeluzole slower in poor metabolizers compared with extensive metabolizers. Conclusions, These results suggest that a) sabeluzole dose should be reduced in patients with severe hepatic dysfunction and b) the AUC of sabeluzole is linked to individual CYP2D6 activity. [source]

Follow-up of an exercise-based treatment for children with reading difficulties

DYSLEXIA, Issue 2 2007
David Reynolds
Abstract This study reports the results of a long-term follow-up of an exercise-based approach to dyslexia-related disorders (Reynolds, Nicolson, & Hambly, Dyslexia, 2003; 9(1): 48,71). In the initial study, children at risk of dyslexia were identified in 3 years of a junior school. One half then undertook a 6 month, home-based exercise programme. Evaluation after 6 months indicated that the exercise group improved significantly more than the controls on a range of cognitive and motor skills. Critics had suggested that the improvement might be attributable to artifactual issues including Hawthorne effects; an initial literacy imbalance between the groups; and inclusion of non-dyslexic participants. The present study evaluated the issue of whether the gains were maintained over the following 18 months, and whether they were in some sense artifactual as postulated by critics of the original study. Comparison of (age-adjusted) initial and follow-up performance indicated significant gains in motor skill, speech/language fluency, phonology, and working memory. Both dyslexic and non-dyslexic low achieving children benefited. There was also a highly significant reduction in the incidence of symptoms of inattention. Interestingly there were no significant changes in speeded tests of reading and spelling, but there was a significant improvement in (age-adjusted) reading (NFER). It is concluded that the gains were indeed long-lasting, and that the alternative hypotheses based on potential artifacts were untenable, and that the exercise treatment therefore achieved its applied purpose. Further research is needed to determine the underlying reasons for the benefits. Possible (and potentially synergistic) explanations include: improved cerebellar function (neural level); improved learning ability and/or attentional ability (cognitive level); improved self-esteem and self-efficacy (affective level); and improved parental/familial support (social level). Copyright © 2006 John Wiley & Sons, Ltd. [source]

Perspectives of multi-modal contribution of honeybee resources to our life

ENTOMOLOGICAL RESEARCH, Issue 2008
Hidehiro HOSHIBA
Abstract The European honeybee, Apis mellifera, has been introduced to all continents and their products like honey, propolis, royal jelly and beeswax are well known. However, its contribution is not restricted to such direct products but extends into a much wider area. For example, the economic value of seed production by pollination exceeds the above-mentioned bee products. The application of F1 hybrid is increased to as much as 70% of commercial crops and flowers in Japan and honeybees are important pollinators in the F1 seed production. Incorporation into the large-scale biodiesel fuel production system by culturing rape and sunflower seeds etc. is relied on because it is good to construct possible zero-emission systems that reduce carbon dioxide and increase the rich by-products like honey and royal jelly. Bees' higher brain function and sophisticated social system of the colony opens new perspectives as a model system. Their individual ability to recognize even abstract concepts is comparable to that of higher primates. Rats or mice have no such ability. High performance learning ability of bees associated with proboscis extension reflex can be used to detect drugs at the airport. Function of the colony, on the other hand, is an excellent model for social physiology or a self-organization system. After the whole genome of A. mellifera was read in 2006 by the world consortium, consisting of more than 90 institutions from all over the world, many molecular biologists are coming into bee world. Nobody has yet succeeded in the challenge to make transgenic honeybee, so far, because of the difficulty in controlling the reproductive system headed by the queen. However, if someone succeeded in a breakthrough we will have stingless honeybees and a disease-resistant strain in the future. [source]

Open-field Behaviors and Water-maze Learning in the F Substrain of Ihara Epileptic Rats

EPILEPSIA, Issue 1 2006
Yoko Okaichi
Summary:,Purpose: Genetically epileptic model rats, Ihara epileptic rat (IER/F substrain), have neuropathologic abnormalities and develop generalized convulsive seizures when they reach the age of ,5 months. Because the neuromorphologic abnormalities are centered in the hippocampus, we expected to observe spatial cognitive deficits. The present study aimed to evaluate emotionality and learning ability of the F substrain of IER. Methods: To determine whether deficits are caused by inborn neuropathologic abnormalities or by repeated generalized convulsions, we tested nine 6- to 12-week-old IER/F rats that had not yet experienced seizures (experiment 1) and nine 7- to 9-month-old IER/F rats that had repeatedly experienced seizures (experiment 2) with identical tasks: an open-field test and the Morris water-maze place and cue tasks. Results: Both groups of IER/Fs showed behaviors that were different from those of control rats in the open-field test, and extensive learning impairments were seen in both the place task, which requires spatial cognition, and the cue task, which does not require spatial cognition but requires simple association learning. Their impaired performance of the cue task indicates that their deficiency was not limited to spatial cognition. Conclusions: Because young IER/F rats without seizure experiences also showed severe learning impairments, genetically programmed microdysgenesis in the hippocampus was suspected as a cause of the severe learning deficits of IER/Fs. [source]

A test of the opponent-process theory of motivation using lesions that selectively block morphine reward

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 12 2007
Hector Vargas-Perez
Abstract The opponent-process theory of motivation postulates that motivational stimuli activate a rewarding process that is followed by an opposed aversive process in a homeostatic control mechanism. Thus, an acute injection of morphine in nondependent animals should evoke an acute rewarding response, followed by a later aversive response. Indeed, the tegmental pedunculopontine nucleus (TPP) mediates the rewarding effects of opiates in previously morphine-naive animals, but not other unconditioned effects of opiates, or learning ability. The aversive opponent process for acute morphine reward was revealed using a place-conditioning paradigm. The conditioned place aversion induced by 16-h spontaneous morphine withdrawal from an acute morphine injection in nondependent rats was abolished by TPP lesions performed prior to drug experience. However, TPP-lesioned rats did show conditioned aversions for an environment paired with the acute administration of the opioid antagonist naloxone, which blocks endogenous opioids. The results show that blocking the rewarding effects of morphine with TPP lesions also blocked the opponent aversive effects of acute morphine withdrawal in nondependent animals. Thus, this spontaneous withdrawal aversion (the opponent process) is induced by the acute rewarding effects of morphine and not by other unconditioned effects of morphine, the pharmacological effects of morphine or endogenous opioids being displaced from opiate receptors. [source]

LEARNING ABILITY AND LONGEVITY: A SYMMETRICAL EVOLUTIONARY TRADE-OFF IN DROSOPHILA

A connectionist production system which can perform both modus ponens and modus tollens simultaneously

EXPERT SYSTEMS, Issue 1 2000
Minoru AsogawaArticle first published online: 16 DEC 200
Modus ponens is used in forward inference and backward inference, where the truth of the conclusion is inferred from the truth of the premise. In modus tollens, the falseness of the premise is inferred from the falseness of the conclusion. Although modus ponens is used in general connectionist production systems, modus tollens is rarely used, except in Quinlan's proposed INFERNO system and in the system proposed by Thornber. A connectionist production system called ConnPS that can perform both modus ponens and modus tollens simultaneously is described. Compared to the INFERNO system, one of the advantages of ConnPS is its supervised learning ability. The rules and examples given as external knowledge are often erroneous and incomplete. In ConnPS, these rules can be refined by using the supervised learning. Both positive and negative examples are presented to ConnPS, onto which the external rules and observations are mapped. Moreover, ConnPS's implementations of implications, conjunctions, disjunctions and negation are intuitively consistent with Boolean logic. [source]

Incremental learning of collaborative classifier agents with new class acquisition: An incremental genetic algorithm approach

INTERNATIONAL JOURNAL OF INTELLIGENT SYSTEMS, Issue 11 2003
Sheng-Uei Guan
A number of soft computing approaches such as neural networks, evolutionary algorithms, and fuzzy logic have been widely used for classifier agents to adaptively evolve solutions on classification problems. However, most work in the literature focuses on the learning ability of the individual classifier agent. This article explores incremental, collaborative learning in a multiagent environment. We use the genetic algorithm (GA) and incremental GA (IGA) as the main techniques to evolve the rule set for classification and apply new class acquisition as a typical example to illustrate the incremental, collaborative learning capability of classifier agents. Benchmark data sets are used to evaluate proposed approaches. The results show that GA and IGA can be used successfully for collaborative learning among classifier agents. © 2003 Wiley Periodicals, Inc. [source]

Dietary restriction inhibits spatial learning ability and hippocampal cell proliferation in rats,

JAPANESE PSYCHOLOGICAL RESEARCH, Issue 1 2008
SHUICHI YANAI
Abstract: We investigated the effect of dietary restriction on spatial learning ability and hippocampal cell proliferation in adult rats using two spatial learning tasks and immunohistochemical staining with 5-bromo-2,-deoxyuridine (BrdU). Sixteen rats were divided into restricted or ad lib feeding groups at 70 days of age, and were trained in the delayed-matching-to-place (DMTP) task (a working memory task) from 93 days of age, and then the Morris water maze task (a reference memory task). Dietary restriction had no effect on the DMTP task with 30 s delay and on the water maze task. However, in the DMTP task with 30 min delay, restricted rats performed significantly more poorly than ad lib rats. Quantitative analysis of hippocampal cell proliferation revealed that the density of newborn cells in restricted rats was significantly lower than that in ad lib rats. These results suggest that a loss of proliferating capacity in the hippocampus may be a candidate for an anatomical and biological basis for the cognitive decline caused by dietary restriction. [source]