Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Reversal Learning”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,639 records · Page 91Linked to original sources
PubMed2001

Snoring during early childhood and academic performance at ages thirteen to fourteen years.

OBJECTIVES: Obstructive sleep apnea syndrome in young children is associated with an adverse effect on learning. However, the long-term impact of sleep-disordered breathing (SDB) during early childhood on learning remains unknown. METHODS: Questionnaires were mailed to seventh and eighth graders attending public schools whose class ranking was either in the top 25% (high performance [HP]) or bottom 25% of their class (low performance [LP]), and who were matched for age, gender, race, school, and street of residence. Snoring frequency and loudness at 2 to 6 years of age, tonsillectomy and adenoidectomy (T&A) for snoring or recurrent infection, school grades, and parental smoking and snoring were assessed. RESULTS: The questionnaire response rate was 82.8%. Because of ongoing ring, 13 responders were excluded, such that 1588 questionnaires could be analyzed (797 in LP and 791 in HP group). Frequent and loud snoring during early childhood was reported in 103 LP children (12.9%) compared with 40 HP children (5.1%; odds ratio: 2.79; confidence interval: 1.88-4.15). Furthermore, 24 LP and 7 HP children underwent T&A for snoring (odds ratio: 3.40; confidence interval: 1.47-7.84), while 21 LP and 19 HP children required surgery for recurrent tonsillitis. CONCLUSIONS: Children with lower academic performance in middle school are more likely to have snored during early childhood and to require T&A for snoring compared with better performing schoolmates. These findings support the concept that SDB-associated neurocognitive morbidity may be only partially reversible or that a "learning debt" may develop with SDB during early childhood and hamper subsequent school performance.

Achievement↗
PubMed2004

Using prior knowledge to improve genetic network reconstruction from microarray data.

The use of Bayesian Network methods to recover transcriptional regulatory networks from static microarray data is an active area of bioinformatics research. However, early work in this area lacked realistic analysis of the effects of data set size on learning performance and ignored the potentially immense benefits of using prior biological knowledge. More recent work which has utilized such information has tended to focus on qualitative descriptions of the results. In this paper, we construct a detailed, realistic model for glucose homeostasis and use this model to generate static, synthetic gene expression data. We then use a Bayesian Network method to reconstruct this genetic network from the synthetic microarray data utilizing various amounts and types of prior knowledge. By quantitatively analyzing the effects of data set size and the incorporation of different types of prior biological knowledge on our ability to reconstruct the original network, we show that characteristic portions of genetic networks can be reconstructed from microarray data. Incorporating prior knowledge into the learning scheme greatly reduces the data required, allowing these reverse engineering techniques to be used to learn regulatory interactions from microarray data sets of realistic size.

Bayes Theorem↗
PubMed1997

Memory and aphasia.

Sixty-one acute and 17 chronic vascular left-hemisphere damaged patients were tested with five memory tasks that investigated verbal short-term (digit span) and long-term (paired-associate and story learning) memory, and spatial short- and long-term memory (Corsi's span and learning). Both brain-damaged groups were significantly impaired in all memory tasks (except for chronic patients in the story learning task) compared to normal controls. The presence of aphasia and locus of lesion (anterior, posterior and deep) had no effect on the memory impairment, with only one exception of paired-associate learning that was better performed by non-aphasic than aphasic patients. Eleven subjects were better at paired-associate learning than story recall, the reverse dissociation was never found. Finally, chronic patients performed significantly better than acute patients only in the Corsi's learning task.

Acute Disease↗
PubMed1992

CGS 5649 B, a new compound, reverses age-related cognitive dysfunctions in rats.

CGS 5649 B improves the learning performance of aged rats in a one-way active-avoidance situation. If, under reversed conditions, treated aged rats are also tested for passive avoidance, they show "place learning," which our findings have demonstrated to be typical of young rats. The effects of the substance are not confined to these experimental models nor are they species specific: it also facilitates passive avoidance in mice and social learning in rats. The compound is effective if administered before or immediately after the learning trial.

Aging↗
PubMed1983

Host genetics and the behavioral sequelae to herpes encephalitis in mice.

The effects of intracerebral infection with herpes simplex virus on the subsequent behavior of two strains of mice were examined. Infected Nya:NYLAR mice were hyperactive and did not show any deficits in the acquisition or reversal of a spatial learning task. In contrast, infected Nya:(SW) mice were hypoactive and made more errors than controls during both phases of the learning tasks. These differences in the nature of the sequelae to infection were related to an overall higher virus titer in the brains of Nya:(SW) mice, an effect particularly marked in the cerebral hemispheres. The results suggest that herpes encephalitis may produce a variety of behavioral syndromes, depending in part on the genetic background of the host. The relevance of these findings to clinical disorders produced by viral infection is discussed.

Analysis of Variance↗
PubMed1995

Reversal of age-dependent cognitive impairments and cholinergic neuron atrophy by NGF-secreting neural progenitors grafted to the basal forebrain.

A highly NGF-secreting cell line was generated by retroviral transduction of a conditionally immortalized CNS-derived neural progenitor cell line. After transplantation to the nucleus basalis magnocellularis (NBM), the cells continue to express the NGF transgene for at least 10 weeks, producing sufficient NGF to reverse cholinergic neuron atrophy in aged rats and induce cellular hypertrophy in young rats. In cognitively impaired aged rats, transplants of the NGF-secreting cells placed either in the NBM and septum or in only the NBM induced a near-complete reversal of the spatial learning impairment. This was accompanied by a normalization of the size of the cholinergic neurons in the grafted areas. The results demonstrate that locally increased supply of NGF to the basal forebrain cholinergic nuclei has a significant impact on cognitive function and support the usefulness of neural progenitor cells for a long-term localized delivery of neurotrophins to the CNS.

Age Factors↗
PubMed2006

A new test for long-term spatial memory using an operant chamber in mice.

As part of ongoing efforts to develop fully automated and standardized behavioral tasks to probe cognitive and mnemonic capabilities of mice, we have constructed a new rectangular operant chamber. The chamber contains numerous nose poke holes, distributed over three of its inner walls that are identifiable by their spatial locations. Using this apparatus, we have developed a 'spatial' memory task using a successive reversal discrimination paradigm. Mice learn to discriminate, by trial and error, the position of a single valid hole during a Presentation session wherein they obtained a maximum of 20 reinforcements or 15 min time elapsed. Following a delay interval, they were resubmitted to the same task (Test) using the same reinforced hole. Results indicated that C57BL/6 mice exhibited a significant improvement during the Test, the magnitude of the improvement (memory savings) being dependent on the length of retention intervals ranging from 5 min to 24h. In addition, discrimination performance was sensitive to scopolamine in a dose dependent manner. The simplicity in task set up and the minimal labor and space requirements make this task suitable for high throughput behavioral characterization of genetically modified mice.

Analysis of Variance↗
PubMed2002

Behavioral effects of excitotoxic lesions of ventral medial prefrontal cortex in the rat are hemisphere-dependent.

The ventral region of the medial prefrontal cortex (mPFC) is highly sensitive to stressful inputs and implicated in a variety of behaviors. Studies have also demonstrated numerous functional hemispheric asymmetries within this brain area of the rat. The present study examines the effects of ibotenic acid or sham lesions targeting the left, right or bilateral infralimbic cortex, on a variety of behaviors. Lesions (which destroyed infralimbic and ventral prelimbic cortex) were without effect on acquisition or reversal of a spatial learning task in the Morris water maze. Similarly unaffected were spontaneous and amphetamine-induced locomotor activity and sensitization, and prepulse inhibition of the acoustic startle response. In contrast, lesions significantly affected behavior in the elevated plus maze, as right-lesioned animals spent more time exploring the open arms of the maze than shams or left-lesioned rats, while not differing in closed arm entries. As well, in a simple taste aversion paradigm, right-lesioned rats drank significantly more of a sweetened milk/quinine solution than shams and left-lesioned rats, despite not differing in consumption of sweetened milk alone. The anxiolytic effects of right, but not left lesions of ventral mPFC, parallel the asymmetrical suppression of physiological stress responses previously reported for similar lesions. It is suggested that the right ventral mPFC plays a primary role in optimizing cautious and adaptive behavior in potentially threatening situations.

Animals↗
PubMed1997

Influence of nefiracetam on NGF-induced neuritogenesis and neural cell adhesion molecule polysialic acid expression: in vivo and in vitro comparisons.

Previously, the ability of co-administered nefiracetam to reverse scopolamine-induced learning deficits has been attributed to the preservation of a transient increase in neural cell adhesion molecule (NCAM) polysialylation state during a late phase of memory consolidation (Doyle et al., J. Neurosci. Res., 31 (1992) 513-523). Using the PC-12 pheochromocytoma cell model, we now demonstrate nefiracetam pre-exposure to significantly enhance nerve growth factor-induced neuritogenesis and NCAM polysialylation, but not prevalence, in a dose-dependent manner with maximal effects being observed at the lowest dose (0.1 microM) examined. As the memory-associated increase in NCAM polysialylation in vivo is associated with a defined group of neurons at the dentate hilar/granule cell layer border (Regan and Fox, Neurochem. Res., 20 (1995) 521-526), the effect of chronic nefiracetam exposure in vivo was evaluated. Once-daily, intraperitoneal administration of either 3 or 9 mg/kg nefiracetam to adult male Wistar rats for 40 days significantly increased the number of hippocampal dentate polysialylated neurons only at the highest dose evaluated, suggesting it to prevent their age-dependent decline. These results are consistent with nefiracetam facilitating early induction events of long-term memory consolidation processes involving NCAM polysialylation state.

Aging↗
PubMed2001

Current overview of the pathogenesis and prophylaxis of measles with focus on practical implications.

Measles is one of the most important diseases of mankind, which is so highly contagious and evokes such persistent immunity that the virus cannot be sustained in a population of less than about 500,000 persons. The first of the licensed live virus vaccines against measles was developed empirically and was approved in 1963. It provides high level and lasting immunity and is a paradigm for solving major medical problems without really understanding them. In spite of means for control by prophylactic immunization, research on measles infection continues to be part of the effort to understand the pathogenesis of many different viruses, which may have important similarities and differences and provide important insights. Measles, usually, is spontaneously reversible and is a prime model for understanding virus-induced immunodeficiency disease (AIDS) which is rarely reversible. Much has been learned of basic immunology and vaccinology in measles through observation of the inappropriate use of vaccines of appropriate composition, and through inappropriate host response to measles vaccines of inappropriate composition. This review provides a current overview of selected highlights of measles, the virus, its immunopathogenesis, and its control by use of live virus vaccine which may lead to elimination of the disease and eventually to eradication of the virus.

Animals↗