Mirror expression of adrenoleukodystrophy and adrenoleukodystrophy related genes in mouse tissues and human cell lines

In memory-discrimination learning, reward-produced memories are differentially rewarded such that they are the only stimuli available to support discriminative responding. Memory-discrimination learning was used in this study as follows: Reward-produced memories that were assumed to regulate instrumental performance in previously reported extinction and discrimination learning investigations were isolated and explicitly differentially reinforced (prior to a shift to extinction) in each of 4 runway investigations with rats. Results obtained here in the explicit discrimination learning stage and in the subsequent extinction stage were consistent with the prediction of the memory view and with prior discrimination learning and extinction findings. The memory interpretation was applied to memory-discrimination learning, to extinction, and to 2 other types of discrimination learning. It appears that a theory must use reward-produced memories to explain all 4 types of discrimination learning.     

Context, time, and memory retrieval in the interference paradigms of Pavlovian learning.

Reviews research and theory on the "interference paradigms" in Pavlovian learning. In these situations (e.g., extinction, counterconditioning, and latent inhibition), a CS is associated with different unconditioned stimulus/stimuli (UCS) or outcomes in different phases of the experiment; retroactive interference, proactive interference, or both are often observed. In all of the paradigms, contextual stimuli influence performance, and when information is available, so does the passage of time. Memories of both phases are retained, and performance may depend on which is retrieved. Despite the similarity of the paradigms, conditioning theories tend to explain them with separate mechanisms. They also do not provide an adequate account of the context's role, fail to predict the effects of time, and overemphasize the role of learning or storage deficits. By accepting 4 propositions about animal memory (i.e., contextual stimuli guide retrieval, time is a context, different memories are differentially dependent on context, and interference occurs at performance output), a memory retrieval framework can provide an integrated account of context, time, and performance in the various paradigms. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Time between events as a retrieval cue: Recall and the temporal similarity between the storage and retrieval intervals.

Examined the hypothesis that the time elapsing between events may be a potent cue that accompanies the storage and retrieval of memories. If so, it follows that as the retention interval increases, recall may either increase or decrease, depending on whether the retrieval interval is becoming more similar or less similar to the storage interval. Six experiments employing a runway were conducted, using a total of 102 naive male Holtzman rats as Ss. The target memory to be recalled in acquisition was measured in a subsequent extinction phase in all 6 experiments reported; faster extinction indicated poorer recall in acquisition. Consistent with the present hypothesis, it was found that regardless of whether the retention interval in extinction was long (10–20 min) or short (about 30 sec), resistance to extinction was greater when in acquisition the storage and retrieval intervals were alike (both 30 sec or 10–20 min) rather than different. Results rule out 4 alternative explanations to the present hypothesis: a temporal discrimination view, time tagging the memory of nonreward, generalization decrement occasioned by a change in retention interval from acquisition to extinction, and what was called the last-trial hypothesis. (26 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effects of nucleus basalis magnocellularis lesions in Long-Evans hooded rats on two learning set formation tasks, delayed matching-to-sample learning, and open-field activity.

Rats with quisqualic acid lesions of the nucleus basalis magnocellularis (nBM) and control rats were compared in discrimination reversal learning set (DRLS) and olfactory discrimination learning set (ODLS) tasks, a delayed matching-to-sample task (DMTS), and open-field activity. Evidence of learning set formation was seen to control rats but not in nBM-lesioned rats in the DRLS and ODLS tasks. Better-than-chance performances were seen for both groups in open-field activity. These findings suggest that the nBM is important for higher cognitive processing such as "learning to learn" and thus is important for a complex form of reference memory. In addition, perseverational, working memory, and attentional deficits could not explain learning set impariment after nBM lesions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Acquisition, retention, and extinction of operant discriminations in rats with nucleus basalis magnocellularis lesions.

Effects of bilateral ibotenic acid lesions of nucleus basalis magnocellularis (NBM) and scopolamine treatment on different aspects of learning and memory in an operant discrimination task were assessed. In Experiment 1, NBM lesions impaired acquisition performance. In Experiment 2, scopolamine lowered response rates but did not affect discrimination accuracy in lesioned or control rats. In Experiment 3, although pretrained rats showed transient increases in commission errors, percentage correct responding remained above chance levels after lesion. During extinction in Experiment 4, operant responding diminished more quickly in pretrained NBM-lesioned rats than in controls, but subsequent reacquisition performance was equivalent in both groups. Results suggest the NBM is importantly involved in discrimination learning, but cholinergic activity may be less critical for memory retention than for acquisition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Why there are complementary learning systems in the hippocampus and neocortex: Insights from the successes and failures of connectionist models of learning and memory.

Damage to the hippocampal system disrupts recent memory but leaves remote memory intact. The account presented here suggests that memories are first stored via synaptic changes in the hippocampal system, that these changes support reinstatement of recent memories in the neocortex, that neocortical synapses change a little on each reinstatement, and that remote memory is based on accumulated neocortical changes. Models that learn via changes to connections help explain this organization. These models discover the structure in ensembles of items if learning of each item is gradual and interleaved with learning about other items. This suggests that the neocortex learns slowly to discover the structure in ensembles of experiences. The hippocampal system permits rapid learning of new items without disrupting this structure, and reinstatement of new memories interleaves them with others to integrate them into structured neocortical memory systems. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of ethanol on encoding, consolidation, and expression of extinction following contextual fear conditioning.

Studies of contextual fear conditioning have found that ethanol administered prior to a conditioning session impairs the conditioned freezing response during a test session the next day. The present experiments examined the effects of ethanol on extinction, the loss of conditioned responding that occurs as the animal learns that a previously conditioned context no longer signals shock. Ethanol (1.5 g/kg) administered prior to single (Experiment 1) or multiple (Experiment 2) extinction sessions impaired extinction. Ethanol administered prior to a test session disrupted the expression of freezing after extinction (Experiments 3-5). There was some evidence that ethanol served as an internal stimulus signaling the operation of conditioning or extinction contingencies (Experiments 4-5). In Experiment 6, postsession injections of 1.5 g/kg ethanol had no effect on extinction with brief (3 min) or long (24 min) exposures to the context, but injections of 3 g/kg after long exposures impaired extinction. Together, these results indicate that ethanol affects extinction by acting on multiple learning and performance processes, including attention, memory encoding, and memory expression. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Spatial reversal learning in preclinical scrapie-inoculated mice

Acquisition and reversal of a two-choice spatial discrimination were tested in scrapie-inoculated mice. Both acquisition and reversal were normal in mice tested 138 and 103 days prior to the onset of clinical symptoms. At 65 days before onset of clinical symptoms, scrapie-inoculated mice required more trails to criterion in reversal learning, but this effect was not significant in a second experiment (68 days preclinical) and was transient: no effect was seen 33 days before symptoms. However, the course of reversal learning was abnormal in all three late preclinical groups (68, 65 and 33 days before symptoms). Reversal learning in these three groups was characterized by a rapid extinction of the original discrimination, followed by a period, absent in controls, during which performance showed no further improvement. This effect corresponds in time of onset to the appearance of characteristic neuropathological features.     

Discrimination learning during the first year: Stimulus and positional cues.

In four studies, 3-, 6-, and 9-month-old human infants were tested in a discrimination learning task in which visual fixation to a particular stimulus or lateral position was reinforced with an auditory stimulus. In Experiment 1, all age groups exhibited acquisition, extinction, and reinstatement of fixation to the reinforced target or position. Experiment 2 revealed that 3-month-olds retained the positional discrimination but not the stimulus discrimination after a 5-min delay between acquisition and extinction; older infants retained both types of discriminations. In Experiments 3 and 4 we investigated a possible developmental shift in the dominance of positional versus stimulus cues by training infants on displays in which stimulus and position were confounded and then by dissociating the cues on test trials. Results from both experiments indicated positional cue dominance for young infants and stimulus cue dominance for older infants. The findings are discussed in terms of differences in the attentional demands elicited by proprioceptive versus exteroceptive cues. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

机器学习在深冲钢质量自动判级中的应用

在流程工业中,生产过程需根据客户对产品质量要求进行判级,以满足客户提出的产品质量需求。目前,企业主要采用“事后”抽检方式,但因无法对所有产品实现在线自动判级,常发生索赔和退货,导致我国钢铁企业每年近100亿元损失。为了实现产品质量在线自动判级,提出基于高维数据非线性同等缩放与核简支集类边界确定相结合的质量在线智能判级方法。首先,将高维的工艺参数通过非线性同等缩放算法变换成低维的数据集,并对缩放后数据集进行聚类,分析工艺参数的类分布特征。然后,根据分类后样本的质量指标值分布,采用核简支集类边界算法来确定不同产品质量级别的类边界。最后,依据已确定的类边界,通过质量指标预测实现产品在线判级。通过深冲钢(IF钢)应用实例,证实该方法在训练阶段的在线自动判级准确率达到97.2%,测试阶段的准确率为96%。      

Autobiographical memory: Reports in adolescence.

A prompt word technique was used to investigate the processes of autobiographical memory in 40 adolescents (aged 12–15 yrs) and 40 undergraduates. Three types of prompts were used: object, action, and affect. Prompt type was found to interact with age for both response time and the reported event age of the memories. Results indicate that affect prompts were responded to differentially by college students but not by adolescents. Affective terms were responded to more slowly and with more recent memories by college students. Changes in the nature of conceptual systems, e.g., levels of abstraction, are suggested as a possible explanation for changes in episodic memory performance. (French abstract) (11 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hippocampectomy disrupts the topography of conditioned nictitating membrane responses during reversal learning.

The effects of bilateral hippocampectomy on the topography of conditioned nictitating membrane (NM) responses in 24 male New Zealand white rabbits were examined during 4 learning tasks: 1-tone delay conditioning, unpaired extinction, 2-tone discrimination, and reversal of 2-tone discrimination. Results show that hippocampal ablation altered conditioned NM response topography only during reversal learning and not during the other training paradigms. The shapes of learning curves for hippocampectomized Ss were different from those of controls only during reversal conditioning. Implications for unit-recording studies of hippocampal cellular activity during classical conditioning of the NM response are discussed. (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Intrapair imagery effects in verbal discrimination and incidental associative learning.

Administered 4 study-test trials to 80 17-38 yr. Old students on a verbal discrimination learning (vdl) task where the items varied in imagery (i) value. Ss were then tested for incidental associative learning. The 32-pair mixed list consisted of 8 pairs of high-i and 8 pairs of low-i nouns, and 16 pairs in which 1 item was high-i and the other low-i. For 1/2 of the latter pairs the high-i word was correct. Significantly more errors occurred during vdl with homogeneous low-i pairs than with the other 3 pair types, which did not differ reliably from each other. Incidental associative learning was highest for homogeneous high-i pairs, and stimulus i was more effective than response i when the stimuli had been wrong but not when they had been right during prior vdl. The latter condition was characterized particularly by sharply depressed performance on high-i-low-i pairs. The vdl results are discussed in terms of imagery and frequency hypotheses, and the associative memory data in terms of the effects of the experimental conditions on the amount of attention devoted to 1 or both members during vdl. (french summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Systemic or intrahippocampal delivery of histone deacetylase inhibitors facilitates fear extinction.

Several recent studies have shown that chromatin, the DNA-protein complex that packages genomic DNA, has an important function in learning and memory. Dynamic chromatin modification via histone deacetylase (HDAC) inhibitors and histone acetyltransferases may enhance hippocampal synaptic plasticity and hippocampus-dependent memory. Little is known about the effects of HDAC inhibitors on extinction, a learning process through which the ability of a previously conditioned stimulus, such as a conditioning context, to evoke a conditioned response is diminished. The authors demonstrate that administration of the HDAC inhibitors sodium butyrate (NaB) systemically or trichostatin A (TSA) intrahippocampally prior to a brief (3-min) contextual extinction session causes context-evoked fear to decrease to levels observed with a long (24-min) extinction session. These results suggest that HDAC inhibitors may enhance learning during extinction and are consistent with other studies demonstrating a role for the hippocampus in contextual extinction. Molecular and behavioral mechanisms through which this enhanced extinction effect may occur are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Psychotherapy as a learning process.

If one accepts the view that psychotherapy is a learning process, then greater efforts should be made to develop treatment methods derived from our knowledge of learning and motivation. The learning mechanisms of counterconditioning, extinction, discrimination, reward, punishment, and social imitation are discussed as well as the pertinent research in which these principles were applied to psychotherapy. Some of the more prevalent criticisms of the learning approach to psychotherapy are answered. From Psyc Abstracts 36:02:2IF43B. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reality monitoring.

People remember information from 2 basic sources: external (perceptual processes) and internal (processes such as reasoning, imagination, and thought). Of particular interest are the processes people use in deciding whether information initially had an external or an internal source, i.e., "reality monitoring." A working model of reality monitoring is proposed to account for both discrimination and confusion between memories for thoughts and memories for perceptions. Examples of questions the model addresses are: What types of information are more likely to be represented in memories of external events than in memories of internal events?; What assumptions do individuals have about their memory for their thoughts compared to their memory for their perceptions?; and How accurate are these assumptions? Research that demonstrates the usefulness of the model is summarized. (100 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

mGluR5 positive allosteric modulation enhances extinction learning following cocaine self-administration.

Extinction of classically and instrumentally conditioned behaviors, such as conditioned fear and drug-seeking behavior, is a process of active learning, and recent studies indicate that potentiation of glutamatergic transmission facilitates extinction learning. In this study, the authors investigated the effects of the Type-5 metabotropic glutamate receptors (mGluR5) positive allosteric modulator 3-cyano-N-(1,3-diphenyl-1H-pyrazol-5-yl)benzamide (CDPPB) on the extinction of cocaine-seeking behavior in rats with a history of intravenous cocaine self-administration. To assess its effects on acquisition and consolidation of extinction learning, CDPPB (60 mg/kg) or vehicle was administered either 20 min prior to, or immediately following, each of 10 extinction sessions, respectively. When administered prior to each extinction session, CDPPB produced a significant reduction in the number of active lever presses on all 10 days of extinction training as compared to vehicle-treated animals. When administered following each extinction session, a significant reduction in the number of active lever presses was observed on the 2nd through 10th day of extinction. Both treatment regimens also reduced the number of extinction-training sessions required to meet extinction criteria. Pre- or postextinction-training administration of CDPPB did not alter responding on the inactive lever and had no effects on open field locomotor activity. These data indicate that positive allosteric modulation of mGluR5 receptors facilitates the acquisition and consolidation of extinction learning following cocaine self-administration and may provide a novel pharmacological approach to enhancing extinction learning when combined with cue exposure therapy for the treatment of cocaine addiction. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Sequential and simultaneous feature positive discriminations: Occasion setting and configural learning in human Pavlovian conditioning.

Using a conditioned suppression preparation, the authors investigated sequential (X→A+/A–) versus simultaneous (XA+/A–) feature positive (FP) discrimination learning in humans. The sequential discrimination was expected to be resolved by means of a Feature X Modulated Target A–US association and the simultaneous discrimination by a feature X–US association. After sequential FP training, extinction of Feature X did not affect discriminative X→A/A responding (Experiment 1), and X transferred its modulatory ability only to new targets, B, that had also been modulated (Experiment 2). This suggests that the sequential FP discrimination indeed resulted in occasion setting. Unlike expected, Feature X Extinction did not affect discriminative XA/A responding after simultaneous FP training (Experiment 3), while at the same time Feature X did show the predicted nonselective transfer to new targets, B (Experiment 4). J. M. Pearce's (1987) configural learning theory can account for most but not all findings of Experiments 3 and 4. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A stability bias in human memory: Overestimating remembering and underestimating learning.

The dynamics of human memory are complex and often unintuitive, but certain features—such as the fact that studying results in learning—seem like common knowledge. In 12 experiments, however, participants who were told they would be allowed to study a list of word pairs between 1 and 4 times and then take a cued-recall test predicted little or no learning across trials, notwithstanding their large increases in actual learning. When queried directly, the participants espoused the belief that studying results in learning, but they showed little evidence of that belief in the actual task. These findings, when combined with A. Koriat, R. A. Bjork, L. Sheffer, and S. K. Bar’s (2004) research on judgments of forgetting, suggest a stability bias in human memory—that is, a tendency to assume that the accessibility of one’s memories will remain relatively stable over time rather than benefiting from future learning or suffering from future forgetting. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hippocampal and nonhippocampal contributions to place learning in rats.

Brain structures thought to be critical for learning and memory were lesioned, and the effects on rats' ability to locate food on a radial maze in situations that provided different types of information was used to suggest general principles of information processing by hypothesized neural systems that include each of the lesioned structures. When animals were confined to food-containing and empty arms on different training trials, the learned discrimination between the arms was amygdala based. More training trials were required for ambiguous (adjacent arms) than for unambiguous (widely separated arms) discriminations. When rats moved around and entered both food and no-food arms on the same trial, the unambiguous discrimination was learned by both dorsal striatum- and hippocampus-based systems; however, the ambiguous discrimination was learned only by the hippocampus system. (PsycINFO Database Record (c) 2010 APA, all rights reserved)