几种促智药对樟柳碱所致记忆障碍的改善作用

采用跳台法和避暗法观察中医秘方ＴＣＭ９０１和ＴＣＭ９０２以及脑复智和尼莫地平对樟柳碱所致记忆障碍的改善作用。结果表明,它们均可较好地改善记忆障碍。使动物下跳台或步入暗箱的潜伏期明显延长,并使它们的错误次数明显减少。结果还提示,ＴＣＭ９０１和ＴＣＭ９０２的作用与脑复智和尼莫地平相比,效果几乎相仿,但其中ＴＣＭ９０２的效果似乎更好。     

东莨菪碱所致记忆障碍的脑内突触机制

研究问题是东莨菪碱所致记忆障碍的脑内突触机制,在东莨菪碱所致记忆障碍模型上定量分析屯小鼠海马ＣＡ３区ＧｒａｙＩ突触界面结构参数的变化。     

应激对大鼠行为和部分脑区谷氨酸含量的影响

以旷场试验法测定动物在急、慢性躯体性和心理性应激时的行为变化,以快速断头冷冻匀浆法,用ＨＩＴＡＣＨＩ－８３５氨基酸分析仪测定应激各期视皮层、海马、下丘脑、小脑谷氨酸含量。并对正常动物经侧脑室微量注射Ｌ－ＡＰ４后观察行为变化。结果显示,急性应激期动物行为活动增加,慢性应激期减少：应激时,大鼠部分脑区的谷氨酸含量与对照组相比在不同时期呈显著性差异;侧脑室微量注射Ｌ－ＡＰ４提示行为活动减弱可能与脑内Ｇｌｕ系统的活动有关。     

中药复方对铅染毒大鼠学习记忆障碍的改善作用

应用行为药理学方法研究铅对大鼠学习记忆影响的可能机制,并观察中药复方（驱铅灵）对铅染毒大鼠学习记忆障碍的改善效果。结果：（1）各染毒组大鼠Morris（第一、二、三、五、七轮）测试潜伏期显著延长;记忆保持百分率显著下降。（2）治疗后中药组的大鼠Morris水迷宫第2、3轮测试潜伏期显著短于阳性对照组,记忆保持率显著大于阳性对照组。（4）EDTA组和中药组。结论：中药复方对铅染毒大鼠学习记忆障碍具有良好的改善作用。     

颞叶梗塞致学习记忆障碍的机制研究──微透析分析与超微结构观察

应用光化学的方法建立了颞叶梗塞性学习记忆障碍动物模型。海马区神经介质类氨基酸的变化用微透析技术进行活体动态观测、超微结构改变用ＴＥＭ电镜观察,并同时观察光镜下的神经细胞变化及鼠的学习记忆障碍。结果发现：（１）颞叶梗塞性痴呆鼠其海马区有大量兴奋性和抑制性氨基酸释放;（２）痴呆鼠海马区神经突触有大量囊泡聚集,晚期大小不均;（３）痴呆鼠脑新皮层及海马锥体细胞均有选择性坏死;（４）氨基酸的释放量与选择性神经细胞损伤及学习记忆障碍有关。     

苯二氮类与学习记忆

临床上用于抗焦虑的苯二氮类可导致严重的学习记忆障碍，中枢神经系统内，其主要通过ＧＡＢＡ－Ａ／ＢＺ受体复合物易化ＧＡＢＡ能传递，影响多种记忆过程。已发现的内源苯二氮类具有类似的作用。学习记忆过程会导致脑内源苯二氮类释放，转而调节记忆过程。杏仁，隔区，海马是其参与记忆的关键位点，分别以不同的方式影响一定类型的记忆过程。     

遗忘症记忆障碍脑成像技术定位研究进展

1　引言　　脑成像技术是指以计算机断层扫描 (Ｃｏｍｐｕｔｅｒｉｚｅｄｔｏｍｏｇｒａｐｈｙ ,ＣＴ)、正电子发射断层扫描(ＰｏｓｉｔｒｏｎＥｍｉｓｓｉｏｎＴｏｍｏｇｒａｐｈｙ ,ＰＥＴ)和磁共振成像 (Ｍａｇｎｅｔｉｃｒｅｓｏｎａｎｃｅｉｍａｇｉｎｇ ,ＭＲＩ)三项无创伤显示人大脑结构的影像学技术。尽管这三项技术出现不过才 2 0多年的历史 ,但它在基础研究和临床应用方面已显示出巨大潜力。近年来 ,一些研究者将这三项技术应用于记忆功能和遗忘症损伤定位研究 ,取得了一些重要进展 ,与传统病理学方法相比较 ,有其独特的优越性。…     

不同月龄小鼠行为训练与脑突触蛋白的相关性研究

不同年龄动物在各种行为实验中表现出学习记忆能力不同。一般地说,动物进入中年期以后,记忆保持力(retention)随年龄增长而下降。有关衰老性记忆障碍与脑内神经细胞变化的相关性已有大量观察记载,但中、幼年阶段的记忆力差异及其脑内突触机制     

前额叶切除对于猕猴分辨反转的影响

一、在5只正常猕猴上进行了圆锥体与圆柱体的分辨反转学习训练。对反转后即刻分辨、反转学习速度和长时记忆作了观察。结果表明,随着反复训练,反转后即刻分辨正确率逐步有所提高,反转学习速度也可进一步加快。此外,猴对反转后即刻分辨的长时记忆也是相当巩固的。 二、两侧前额叶背侧面皮层切除后,分辨反转受到影响。这主要表现在反转后即刻分辨的正确率显著下降,动物出现“顽固性”错误。一侧手术后影响不大。     

逆行性遗忘的研究进展

1　前言　　遗忘症是记忆障碍的一种形式 ,其主要表现有顺行性遗忘和逆行性遗忘 ,但病人的短时记忆和智力均正常。顺行性遗忘是指脑受损后被试学习记忆新知识能力的下降 ,而逆行性遗忘是指被试对脑损伤发生之前的事件的记忆障碍 ,又称为远期记忆障碍[1- 2 ] 。相对于顺行性遗忘来说 ,心理学家和神经科学家对于逆行性遗忘的研究较少 ,但它对遗忘症的理论发展、对理解正常的记忆功能及信息在脑内的组织等认知神经科学的基本问题都具有重要的意义。研究逆行性遗忘最常用的测验大致分为两种 :其一是有关公众事件的测验 ,如著名人物 \事件测验。…     

Acetylcholine release in the hippocampus and prelimbic cortex during acquisition of a socially transmitted food preference

Interference with cholinergic functions in hippocampus and prefrontal cortex impairs learning and memory for social transmission of food preference, suggesting that acetylcholine (ACh) release in the two brain regions may be important for acquiring the food preference. This experiment examined release of ACh in the hippocampus and prefrontal cortex of rats during training for social transmission of food preference. After demonstrator rats ate a food with novel flavor and odor, a social transmission of food preference group of rats was allowed to interact with the demonstrators for 30 min, while in vivo microdialysis collected samples for later measurement of ACh release with HPLC methods. A social control group observed a demonstrator that had eaten food without novel flavor and odor. An odor control group was allowed to smell but not ingest food with novel odor. Rats in the social transmission but not control groups preferred the novel food on a trial 48 h later. ACh release in prefrontal cortex, with probes that primarily sampled prelimbic cortex, did not increase during acquisition of the social transmission of food preference, suggesting that training-initiated release of ACh in prelimbic cortex is not necessary for acquisition of the food preference. In contrast, ACh release in the hippocampus increased substantially (200%) upon exposure to a rat that had eaten the novel food. Release in the hippocampus increased significantly less (25%) upon exposure to a rat that had eaten normal food and did not increase significantly in the rats exposed to the novel odor; ACh release in the social transmission group was significantly greater than that of the either of the control groups. Thus, ACh release in the hippocampus but not prelimbic cortex distinguished well the social transmission vs. control conditions, suggesting that cholinergic mechanisms in the hippocampus but not prelimbic cortex are important for acquiring a socially transmitted food preference.     

Muscarinic cholinergic influences in memory consolidation

The central cholinergic system and muscarinic cholinergic receptor (mR) activation have long been associated with cognitive function. Although mR activation is no doubt involved in many aspects of cognitive functioning, the extensive evidence that memory is influenced by cholinergic treatments given after training either systemically or intra-cranially clearly indicates that cholinergic activation via mRs is a critical component in modulation of memory consolidation. Furthermore, the evidence indicates that activation of mRs in the basolateral amygdala (BLA) plays an essential role in enabling other neuromodulatory influences on memory consolidation. Memory can also be affected by posttraining activation of mRs in the hippocampus, striatum and cortex. Evidence of increases in hippocampal and cortical acetylcholine (ACh) levels following learning experiences support the view that endogenous ACh release is involved in long-term memory consolidation. Furthermore, the findings indicating that mR drug treatments influence plasticity in the hippocampus and in sensory cortices strongly suggest that mR activation is involved in the storage of information in these brain regions.     

Perseverative interference with object-in-place scene learning in rhesus monkeys with bilateral ablation of ventrolateral prefrontal cortex

Surgical disconnection of the frontal cortex and inferotemporal cortex severely impairs many aspects of visual learning and memory, including learning of new object-in-place scene memory problems, a monkey model of episodic memory. As part of a study of specialization within prefrontal cortex in visual learning and memory, we tested monkeys with bilateral ablations of ventrolateral prefrontal cortex in object-in-place scene learning. These monkeys were mildly impaired in scene learning relative to their own preoperative performance, similar in severity to that of monkeys with bilateral ablation of orbital prefrontal cortex. An analysis of response types showed that the monkeys with lesions were specifically impaired in responding to negative feedback during learning: The post-operative increase in errors was limited to trials in which the first response to each new problem, made on the basis of trial and error, was incorrect. This perseverative pattern of deficit was not observed in the same analysis of response types in monkeys with bilateral ablations of the orbital prefrontal cortex, who were equally impaired on trials with correct and incorrect first responses. This may represent a specific signature of ventrolateral prefrontal involvement in episodic learning and memory.     

Septohippocampal acetylcholine: involved in but not necessary for learning and memory?

The neurotransmitter acetylcholine (ACh) has been accorded an important role in supporting learning and memory processes in the hippocampus. Cholinergic activity in the hippocampus is correlated with memory, and restoration of ACh in the hippocampus after disruption of the septohippocampal pathway is sufficient to rescue memory. However, selective ablation of cholinergic septohippocampal projections is largely without effect on hippocampal-dependent learning and memory processes. We consider the evidence underlying each of these statements, and the contradictions they pose for understanding the functional role of hippocampal ACh in memory. We suggest that although hippocampal ACh is involved in memory in the intact brain, it is not necessary for many aspects of hippocampal memory function.     

前额叶皮层在学习记忆中的作用

为了探讨前额叶皮层的功能,在被试进行联合搜索作业(Conjunction search task)时,使用跨颅磁刺激干扰被试者右侧前额叶皮层的活动,观察被试者在学习前后的反应时间的变化。观察到磁刺激干扰前额叶的活动,明显地延长了被试者在学习前的反应时间,对学习之后的反应时间几乎没有变化。这说明右侧前额叶参与了记忆的编码,对记忆的提取没有作用。     

Some biochemical and behavioural aspects of the paradoxical sleep window

It has recently been proposed that there is a vulnerable period of time following successful learning when paradoxical sleep (PS) is necessary for learning. This vulnerable time period has been called the PS window. In Experiment 1, the protein synthesis inhibitor anisomycin (ANI) was administered following shuttle avoidance training in the Sprauge-Dawley rat to coincide with the onset of an established PS window. Control groups received either saline or ANI either 3 hours before or 3 hours after the beginning of the PS window. Three hours after the injection, each group was retested. Then animals were immediately sacrificed, and whole brain biochemical analyses were done on levels of acetylcholine (ACh) and activity of acetylcholinesterase (AChE). Only the rats given ANI timed to coincide with the beginning of the PS window showed learning deficits. All ANI-treated groups had less ACh and AChE activity. In Experiment 2, the ACh antagonist scopolamine (SCOP) was injected at the same times as in Experiment 1, and each of these groups had a corresponding saline control group as before. Retesting was done 1 day later; once again, the only group to show learning deficits was the group receiving SCOP timed to coincide with the PS window. Results suggested that the transmitter ACh plays an important role in learning/memory processes at the PS window.     

Age-related differences in the course of cognitive skill acquisition: the role of regional cortical shrinkage and cognitive resources

This study examined the impact of age-related differences in regional cerebral volumes and cognitive resources on acquisition of a cognitive skill. Volumes of brain regions were measured on magnetic resonance images of healthy adults (aged 22-80). At the early stage of learning to solve the Tower of Hanoi puzzle, speed and efficiency were associated with age, prefrontal cortex volume, and working memory. A similar pattern of brain-behavior associations was observed with perseveration measured on the Wisconsin Card Sorting Test. None of the examined structural brain variables were important at the later stages of skill acquisition. When hypertensive participants were excluded, the effect of prefrontal shrinkage on executive aspects of performance was no longer significant, but the effect of working memory remained.     

Evidence for neocortical involvement in reference memory

Rats were trained on an eight-arm radial maze task using a procedure that provides for an assessment of both working and reference memory. Following training, rats received parietal cortex, medial prefrontal cortex, visual cortex, or nucleus basalis magnocellularis lesions. Rats with visual cortex lesions showed no change in performance on either working or reference memory. Rats with parietal cortex lesions displayed a temporary deficit in reference, but no deficit on working memory. Animals with medial prefrontal cortex lesions showed a temporary deficit on both working and reference memory. Rats with extensive lateral frontal and parietal cortex depletion of acetylcholinesterase following nucleus basalis magnocellularis lesions had a marked disruption only of reference but not of working memory. It is concluded that neocortex and possibly the cholinergic projections to neocortex play an important role in mediating reference memory.     

Acetylcholine modulation of neural systems involved in learning and memory

Extensive evidence supports the view that cholinergic mechanisms modulate learning and memory formation. This paper reviews evidence for cholinergic regulation of multiple memory systems, noting that manipulations of cholinergic functions in many neural systems can enhance or impair memory for tasks generally associated with those neural systems. While parallel memory systems can be identified by combining lesions with carefully crafted tasks, most—if not all—tasks require the combinatorial participation of multiple neural systems. This paper offers the hypothesis that the magnitude of acetylcholine (ACh) release in different neural systems may regulate the relative contributions of these systems to learning. Recent studies of ACh release, obtained with in vivo microdialysis samples during training, together with direct injections of cholinergic drugs into different neural systems, provide evidence that release of ACh is important in engaging these systems during learning, and that the extent to which the systems are engaged is associated with individual differences in learning and memory.     

Demonstrating the Effects of Presentation Rate on Aging Memory Using the California Verbal Learning Test (CVLT)

Previous research has repeatedly found that the elderly demonstrate significant declines in direct measures of memory. This study examined verbal learning and memory in the young and old participants using the California Verbal Learning Test (CVLT). We hypothesized that slowing down the presentation rate of a list of words, therefore giving the participants more time to rehearse while learning new information, would decrease the normal differences found between the young and old adults on memory recall. However, at a faster presentation rate, the usual differences would be found. Participants took the CVLT, and correct recall responses were measured as a function of age and presentation rate. It was found, as expected, that at the faster presentation rate, the young did significantly better than the old on recall, but at the slower presentation rate, the differences between age groups diminished. It was concluded that by giving the elderly more time to rehearse information, age-related differences in memory recall could be greatly diminished.