Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Probability 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 1,333 records · Page 74Linked to original sources
PubMed2004

Obstructive jaundice in rats: cause of spatial memory deficits with recovery after biliary decompression.

Children with end-stage liver disease have been found to have cognitive deficits. The aim of this study was to examine whether cholestatic jaundice causes spatial deficits in rats and if these cognitive deficits are reversed by biliary drainage. Rats were randomly divided into three groups. In the first group, the bile duct was ligated for 3 weeks (BDL group); in the second group, the proximal bile duct was ligated with a Broviac CV catheter for 2 weeks followed by a tube bilioduodenostomy (TBD group); in the third group, a sham operation was performed (SHAM group). All the surviving rats were assessed for spatial learning and memory (a major cognitive function in rats) by the Morris water maze task about 3 weeks after the first operation. Blood was aspirated by cardiocentesis and assayed for total bilirubin, albumin, ammonia, and hemoglobin levels on the day following the water maze task. During the four consecutive acquisition trial days of the Morris water maze, jaundiced rats (BDL group) had a significant longer latency to escape than the SHAM group ( p < 0.05). Rats that underwent biliary decompression for 1 week (TBD group) showed improved status of the spatial deficit, as they required less time to reach the escape platform, approaching the performance of the SHAM group. The BDL group had a significantly higher serum ammonia level, higher bilirubin level, and lower hemoglobin level than the other two groups. After biliary decompression for 1 week, the serum albumin concentration in the TBD group still did not return to the level of the SHAM group. The results of this study suggest that long-term cholestasis results in spatial memory deficits in rats that correlate with anemia and hyperbilirubinemia encephalopathy. Early biliary decompression of obstructive jaundice improves spatial memory deficits, possibly related to the recovery of the serum ammonia and hemoglobin levels.

Analysis of Variance↗
PubMed1985

Vasopressin--oxytocin in cerebrospinal fluid of schizophrenic patients and normal controls.

Vasopressin and oxytocin seem to be involved in the processes of learning and memory in animals and probably in man. These peptides appear to have opposite effects in that vasopressin improves memory processes and oxytocin produces amnestic effects. We measured these neuropeptides in the cerebrospinal fluid of schizophrenic patients with and without neuroleptic treatment, psychiatrically healthy controls and drug-free patients before and after three weeks' neuroleptic treatment. There were no significant differences in vasopressin concentrations between schizophrenics and controls. No influence of neuroleptic treatment on vasopressin concentrations was detected. In contrast, concentrations of oxytocin were increased in all schizophrenic patients and were higher in those receiving neuroleptic treatment. In addition, oxytocin concentrations increased after three weeks' neuroleptic treatment. Drug-induced increase of oxytocin concentrations may be of significance in the clinically observed amnestic syndromes and debilitation in schizophrenics treated with neuroleptics.

Adult↗
PubMed1996

Decrease in pacemaker incidence after orthotopic heart transplantation.

A decrease in sinus node dysfunction and pacemaker requirement after orthotopic heart transplantation was observed over a 6.5-year period, probably indicating the effect of a learning curve. Indirect evidence suggests a traumatic genesis of sinus node dysfunction after cardiac transplantation.

Arrhythmia, Sinus↗
PubMed1981

The primary megacystis syndrome.

We discuss 7 cases of the primary megacystis syndrome to demonstrate that the syndrome is non-obstructive and non-neurogenic, and probably of psychogenic origin owing to learned dysfunctional voiding. The major complication is vesicoureteral reflux and initial therapy is aimed at its correction. Prolonged followup and retraining of voiding habits are necessary. Specific pharmacologic or biofeedback techniques are indicated should urodynamic abnormalities of function be evident.

Child↗
PubMed1991

Immortalizing genes of Epstein-Barr virus.

EBV immortalizes human B lymphocytes efficiently. Ten of its approximately 100 genes are expressed in these proliferating lymphoblasts and are candidates for mediating the changes central to the immortalization of the cell. Enough has been learned now about three of these viral genes to indicate that they are likely to be required for immortalization. As more is learned, additional genes of EBV will probably be found to support the process of immortalization of the host cell. EBNA-2 has been shown genetically to be required for EBV to immortalize an infected B lymphocyte. The biochemical activities of EBNA-2 that constitute this requirement have not been identified. Many experiments indicate that EBNA-2 affects the accumulation of specific viral and cellular RNAs. These effects, however, can be detected only in certain EBV-negative B-lymphoblastoid cells. It is, therefore, not clear that the known effects of EBNA-2 adequately explain its ubiquitous requirement in the immortalization of primary human B lymphocytes. LMP is likely to be required for immortalization because it can affect the growth properties of established human lymphoid and epithelial cells and can transform at least two established rodent cells to proliferate in an anchorage-independent manner. The structure of this viral protein, its position in the plasma membrane, many of its biochemical properties, as well as studies of its mutant derivatives are consistent with its acting as a growth factor receptor or affecting the activity of such a receptor. However, no biochemical activity has been assigned directly to LMP, and both its mechanism of action and its possible contribution to immortalization by EBV remain enigmatic. EBNA-1 presumably is required for EBV to immortalize a B lymphocyte because it is essential for the initiation of plasmid DNA replication by EBV. Circumstantial observations indicate also that EBNA-1 is probably necessary for sustaining viral DNA replication in the proliferating cell population. EBNA-1 may well affect the regulation of transcription of viral genes that themselves are required for immortalization. These roles of EBNA-1 are performed in part by its site-specific binding to the elements of oriP required in cis for the replication of EBV plasmid DNAs. It is probable that EBNA-1 also binds both to a set of cellular proteins that function in transcription and to a nonidentical set of cellular proteins that function in replication. EBV effects a fascinating phenotypic change in B lymphocytes it infects. It does so by using several viral genes that alter the physiology of the cell by different means.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acid Sequence↗
PubMed1999

A behavioral analysis of the spatial learning deficit induced by the NMDA receptor antagonist MK-801 (dizocilpine) in the rat.

This study analyzes whether the disruptive effects of the noncompetitive NMDA receptor antagonist MK-801 (0.01-0.1 mg/kg s.c.) on spatial learning can be dissociated from sensorimotor disturbances in the rat. Two different modifications of the Morris swim maze task with a hidden underwater platform were used: with or without local cue. Retention was tested either 24 h or 7 days after training as a probe trial (without platform). The present data indicate that MK-801 produces an impairment of spatial learning that cannot be dissociated from motor or sensory mechanisms. These findings support the view that NMDA receptors probably contribute to, but are not essential for, spatial learning in the water maze.

Animals↗
PubMed2005

Testing the role of semantic similarity in syntactic development.

The study explored early syntactic development, and tested the hypothesis that children use similarity of meaning in order to move beyond the learning of individual item-based multiword constructions. The first 6 types of verb-object (VO) constructions in Hebrew-speaking children were analysed for the occurrence of transfer of learning and facilitation, as well as for the semantic similarity of the direct objects (DO). Longitudinal naturalistic speech corpora of 20 children (1;06-2;06) were analysed. We found facilitation (increased rate of learning) among the first 6 types of VO constructions (each type built on a different verb) as evidenced by the accelerating growth curves. Next, we measured the semantic similarity of the DOs using an 8-category system including Patient, Theme and Object of Result. The first 6 DO types represented 3.95 different semantic roles. On the average, after the first VO construction was learned, 3 out of the following 5 constructions produced were not preceded by another VO construction where the DO was of the same semantic category. The results indicate that facilitation of learning of early syntax is most probably NOT mediated by semantic similarity.

Child Language↗
PubMed2002

Adaptation, punctuation and information: a rate-distortion approach to non-cognitive 'learning plateaus' in evolutionary process.

We extend recent information-theoretic phase transition approaches to evolutionary and cognitive process via the Rate Distortion and Joint Asymptotic Equipartition Theorems, in the circumstance of interaction with a highly structured environment. This suggests that learning plateaus in cognitive systems and punctuated equilibria in evolutionary process are formally analogous, even though evolution is not cognitive. Extending arguments by Adami et al. (2000), we argue that 'adaptation' is the process by which a distorted genetic image of a coherently structured environment is imposed upon a species.

Adaptation, Biological↗
PubMed2004

Distinguishing age differences in knowledge, strategy use, and confidence during strategic skill acquisition.

The authors examined how age differences in strategy selection are related to associative learning deficits and metacognitive variables, including memory ability confidence. In Experiment 1, increases in memory reliance for performance of the noun-pair lookup task were compared with increases in noun-pair memory ability. In Experiment 2, memory reliance was assessed for noun pairs memorized prior to the task. In each experiment, older adults manifested a substantial delay in transition to a retrieval-based strategy despite comparable noun-pair knowledge. In Experiment 3, young and older adults reported comparable confidence ratings for the accuracy of each memory probe response. However, older adults reported lower confidence in their general ability to use the memory retrieval strategy, which correlated with avoidance of the retrieval strategy.

Adolescent↗