普洛托品对正常大鼠学习能力及海马、大脑皮层乙酰胆碱酯酶活性的影响

目的：观察普洛托品（protopine,Pro)对正常大鼠学习能力及海马、大脑皮层乙酰胆碱酯酶活性的影响。方法：大鼠每天Pro 0.5mg/kg灌胃，28d后三等分Y迷宫测定大鼠学习成绩，并测定海马及大脑皮层乙酰胆碱酯酶活性。结果：Pro组大鼠达到学会标准所需的训练次数明显减少，与对照组比较差异有极显著性（P＜0．01），Pro组大鼠海马及大脑皮层乙酰胆碱酯酶活性亦明显降低，与对照组比较差异有显著性（P＜0．01，P＜0．05），结论：Pro可提高正常大鼠学习能力，并降低海马及大脑皮层乙酰胆碱酯酶活性。     

Serial order short-term memory capacities and specific language impairment: No evidence for a causal association

This study re-explored the nature of verbal short-term memory (STM) deficits in children with specific language impairment (SLI), by distinguishing item and serial order STM processes. Recent studies have shown serial order STM capacity to be a critical determinant of language development, relative to item STM. In Experiment 1, 12 children with SLI, 12 age-matched children and 12 language-matched children were administered serial order recognition and reconstruction tasks. Experiment 2 assessed implicit serial learning abilities via a Hebb learning task. The SLI group showed impaired performance for the serial order reconstruction and recognition tasks, relative to language-matched and/or age-matched control groups. However, normal serial position effects were observed in all SLI children in the serial order reconstruction task, suggesting normal coding of serial position information. Similarly, performance on the Hebb serial learning task was at chronological age appropriate levels. Experiment 3 showed that the group differences observed for the serial order STM tasks in Experiment 1 disappeared when the SLI group was compared to a mental age-matched control group. Experiment 4 showed similar performance levels in the SLI group and the mental age-matched control group for a nonword recognition task assessing item STM capacities. This study shows that children with SLI have no specific impairments for serial order and item STM components but that poorer general cognitive efficiency is related to functional limitations in verbal STM tasks. The data are in line with limited information processing accounts of SLI.     

Generalization of Frequency Discrimination Learning Across Frequencies and Ears: Implications for Underlying Neural Mechanisms in Humans

Frequency discrimination thresholds (FDTs) at 750, 1500, 3000, and 6000 Hz were measured in 32 normal-hearing listeners before and after each listener practiced the task for 12 h at one of the above frequencies using a single ear. Marked improvements in thresholds taking place over several hours were observed during the frequency- and ear-specific training period. Comparisons between pre- and posttraining thresholds showed large improvements at the trained frequency, but also at other frequencies. The improvements were initially slightly—but significantly—larger at the trained frequency than at untrained frequencies. However, this trained-frequency advantage disappeared rapidly during the course of the two-hour multifrequency posttraining session, suggesting rapid relearning or learning generalization across frequencies. In contrast, no significant ear specificity was found, not even at early stages of the posttraining session. These findings add to earlier results suggesting that, in humans, frequency discrimination learning is only weakly frequency-specific, and they reveal that a complete generalization across frequencies can occur rapidly with little retraining at the initially untrained frequencies. Implications regarding underlying mechanisms are discussed.     

学习优良与不良中学生记忆特点的比较研究

目的探讨学习优良和不良中学生的记忆特点,为学习不良学生的教育提供科学依据。方法采用北京大学PES心理实验系统中的内隐记忆实验对学习优良和学习不良中学生各16名进行测试。结果学习优良和学习不良中学生的启动效应值均值分别为0.29和0.34,差异无统计学意义(P>0.05);学习优良与不良中学生的再认保持量均值分别为30.00和25.25,差异有统计学意义(P<0.01)。结论学习优良和不良中学生的内隐记忆无差异,学习优良中学生外显记忆优于学习不良中学生。提高学习不良学生的学习成绩应从外显记忆着手,同时兼顾内隐记忆的作用。     

神经节苷酯对老年性学习记忆减退鼠空间学习记忆能力的影响

目的研究神经节苷酯对老年性学习记忆减退鼠空间学习记忆的影响。方法用Ｍｏｒｉｓ水迷宫筛选老年性学习记忆减退昆明小鼠，腹腔注射神经节苷酯１４天，然后测试小鼠定位航行和空间探索能力。结果与老年学习记忆减退鼠对照组比较，治疗组平均逃避潜伏期缩短，原平台游泳距离和穿环数次却增大，但均未达到老年学习记忆正常组和青年组水平。结论提示神经节苷酯可改善老年性学习记忆减退鼠空间学习记忆能力。     

Diazepam impairs place learning in naive but not in maze-experienced rats in the Morris water maze

Anxiolytic benzodiazepines have been shown to impair place learning in the Morris water maze. However, a clear-cut demonstration of a direct and specific effect on mnemonic processes has not yet been offered. In the present study, the effects of diazepam on place navigation in the Morris water maze were studied in rats. Three conditions were examined: learning, reversal learning and learning after familiarisation of animals with the maze. In view of the anxiolytic and sedative properties of diazepam, appropriate doses of the drug, i.e. those that produced an anxiolytic effect but no major motor impairment, were initially selected in the water-lick conflict and rotarod tests, respectively. Doses of 2.5 and 5 mg/kg PO increased punished drinking in the water-lick conflict test without significantly decreasing rotarod performance. These doses were then used to assess the effects of diazepam on spatial behaviour. Diazepam, at both doses, impaired place learning in behaviourally naive rats. Such an effect appeared to be transient: diazepam-treated rats eventually reached control performance. Moreover, analysis of the probe trial at the end of training revealed adoption of a spatial strategy to locate the submerged platform. Neither reversal learning nor learning after familiarisation was affected. These results do not replicate previous findings in the Morris water maze and provide some evidence that the diazepam-induced place learning deficit may be primarily anxiolytic in nature.     

全身麻醉药物对学习记忆功能的影响

全身麻醉药物通过对中枢多种神经递质和受体系统的影响，调节神经突触传递可塑性的改变，从而对学习记忆功能产生广泛作用。深入考察全身麻醉药物对学习记忆功能的影响，将为合理解释术中残留记忆和术后认知功能障碍的发生机制，婴幼儿和老年痴呆患者手术期间选择合适的全身麻醉药物和方法提供借鉴。     

一次阿扑吗啡注射对大鼠视觉辨别学习和工作记忆的影响

目的探讨多巴胺受体激动剂 -阿扑吗啡对大鼠视觉辨别学习和工作记忆的影响。方法利用旋转T迷宫装置 ,通过食物强化 ,分别训练大鼠正常和逆反的视觉辨别学习任务。动物达到规定的标准次数后 ,腹腔注射 2mg/kg体重的阿扑吗啡 ,3 0分钟后观察药物对工作记忆的影响。 结果对于正常学习 ,阿扑吗啡注射组动物的正确次数与生理盐水对照组相比无显著性差异 ,且两组动物继续进行逆反学习训练 ,达到学习标准所需的总次数亦无显著性差异 ;对于逆反学习 ,阿扑吗啡注射组动物的正确次数较对照组显著降低。结论单独一次阿扑吗啡注射可能干扰大鼠逆反学习的工作记忆 ,但不影响正常学习的工作记忆和逆反学习的过程。     

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

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.