小鸡一次性被动回避模型行为特点的研究

本文系统地观察了一日龄小鸡在一次性被动回避模型中的行为特点,其主要结果如下：１）用１００％ＭｅＡ训练的动物在训练后５至１８０分钟之间表现出良好的辨别记忆能力,但在训练后１５分钟可见到一次短暂的遗忘现象;２）用２０％ＭｅＡ训练的动物虽然短时记忆和部分中时记忆良好,但不能形成长时记忆。文中比较了上述结果与有关文献之间的异同,并对刺激强度与长时记忆之间的关系进行了讨论。     

荷苞牡丹碱对雏鸡单眼视剥夺后记忆形成过程的改善作用

了雏鸡左眼视剥夺２小时后,进行一次性被动回避学习的记忆形成过程;以及ｒ一氨基丁酸（ｒ－ａｍｉｎｏ－ｂｕｔｙｒｉｃａｃｉｄＧＡＢＡ）的受体颉颌颃剂荷苞牡丹碱（ｂｉｃｕｃｕｌｌｉｎｅＢｉｃ）,对雏鸡左眼视剥夺后记忆形成过程的改善作用。实验结果表明：１．雏鸡左眼视剥夺２小时后,仅能形成较好的短时记忆,中时记忆和长时记忆难以形成;２．训练前１０分钟颅内注射荷苞牡丹碱,对雏鸡左眼视剥夺２小时后的记忆缺失有明显的改善作用,形成了较好的中时记忆和长时记忆。     

荷包牡丹碱对受低强度训练的小鸡的记忆形成的影响

在小鸡一次性被动回避行为中,低强度训练的动物其长时记忆保持不良,而训练前１０或２０分钟注射γ－氨基丁酸能颉颃剂荷包牡丹碱,可明显提高长时记忆的保持水平,这一作用可被激动剂蝇蕈碱反转。记忆保持曲线进一步显示,受低强度训练的动物其记忆仅能保持至训练后２０分钟,而注射荷包牡丹碱可使记忆至少延长至训练后１２０分钟。上述结果提示：小鸡的记忆形成受γ－氨基丁酸能系统的调节;γ－氨基丁酸能系统虽然直接参与中时记忆,但对长时记忆的形成似乎也是必需的。     

剥夺左眼和单眼学习与雏鸡脑内Jun样蛋白表达的相关性研究

利用免疫组化技术,观察并比较剥夺一侧视觉及单眼一次性味觉厌恶回避学习后Ｊｕｎ样蛋白在雏鸡ＨＶ和ＬＰＯ的表达,结果表明正常雏鸡ＨＶ、ＬＰＯＪｕｎ表达几乎没有,剥夺左眼和单眼视觉学习后均可使Ｊｕｎ样蛋白增高。根据阳性神经元记数结果表明：１．视剥夺２．５、４、２４小时后可使Ｊｕｎ样蛋白的表达逐渐增高,而且它们之间的差异显著;２．剥夺左眼２小时和２４小时后训练,并分别于１０分钟、７０分钟记忆保持测验后可看到Ｊｕｎ样蛋白表达继续增多;３。无论单纯视剥夺组还是单眼视觉学习组,各组ＬＰＯＪｕｎ样蛋白的表达均明显高于ＨＶ的Ｊｕｎ样蛋白表达,它们之间差异显著。     

中枢胆碱能系统在小鸡记忆形成过程中的作用

中枢胆碱能系统在记忆形成过程中的特异性作用仍有待于进一步探讨。该研究观察了东莨菪碱对小鸡一次性被动回避行为的影响,主要结果如下：１．训练前颅内注射一定剂量的东莨菪碱可引起一日龄小鸡的记忆障碍;２．无论是训练前１５分钟还是训练前３０分钟注射,东莨菪碱引起的记忆障碍均起始于训练后１５－２０分钟之间;３．研究中所用剂量的东莨菪碱不影响小鸡的啄食行为、味觉功能及兴奋水平。上述结果提示,中枢胆碱能系统可能较特异性地参与中时记忆的形成过程。     

雏鸡左眼视剥夺不同时程后记忆形成过程与脑内Jun样蛋白表达差异的研究

本实验采用一次性味觉厌恶回避学习,研究２日龄雏鸡左眼视剥夺２４小时后的记忆形成过程,并与左眼视剥夺２小时后的记忆形成过程进行比较,同时利用免疫组化技术,观察并比较单眼视剥夺不同时程及单眼学习后Ｊｕｎ样蛋白在雏鸡脑内不同区域（ＨＶ和ＬＰＯ）的表达。结果表明：１．视剥夺左眼２４小时后对雏鸡的短时记忆、中时记忆和长时记忆均无明显影响,但中时记忆保持水平略低于双眼学习条件下的中时记忆保持水平。这与视剥夺２     

加工深度和元记忆训练对多重记忆系统监测的影响

这项研究探讨元记忆判断对情节记忆系统、语义记忆系统和ＰＲＳ（ｐｅｒｃｅｐｔｕａｌｒｅｐｒｅｓｅｎｔａｔｉｏｎ）系统的监测问题。已有的研究表明,元记忆对情节记忆的监测好于对语义记忆的监测。这项研究在深度加工和元记忆训练的条件下,进一步比较了Ｒ反应（Ｒｒｅｓｐｏｎｓｅｓ）项目、Ｋ反应（Ｋｒｅｓｐｏｎｓｅｓ）项目以及成功补笔项目的ＦＯＫ幅度（ＭＦＯＫ,ｍａｇｎｉｔｕｄｅｏｆＦＯＫ）。结果表明,无论是在深度加工的条件下,还是在元记忆训练的条件下,Ｒ项目的ＭＦＯＫ明最高于Ｋ项目和成功补笔项目。这说明元记忆系统的监测模式具有相对的稳定性,它不受记忆痕迹的性质与元记忆判断策略的影响。     

厌恶与恐惧面孔的记忆编码、保持、提取

情绪记忆增强效应在负性情绪记忆研究中被反复证实。尽管厌恶和恐惧同属负性情绪, 提示威胁的存在, 但由于它们的进化意义和生理功能不同, 可能导致它们对记忆的编码、保持、提取三个阶段不同的调节方向或调节强度。本文采用延迟再认任务, 采用事件相关电位考察健康成年被试对唤醒度和效价相当的恐惧和厌恶面孔的记忆编码、保持和提取。结果显示, 1)在记忆编码的早期, 被试主要加强了对恐惧面孔的注意(P1)和结构编码(N170), 而厌恶信息的加工受到了抑制; 2)从记忆编码晚期到记忆保持的整个阶段, 被试对厌恶信息的精细评估(编码阶段P3)和复述保持(保持阶段的负走向慢波)均强于恐惧信息; 3)相比于恐惧面孔, 厌恶面孔可能在工作记忆系统形成了更强的表征, 从而使被试在记忆提取时可回忆起更多的细节, 对记忆提取的信心更足(提取阶段P3)。这后两条发现是导致行为层面上厌恶情绪记忆优于恐惧情绪记忆的原因。本研究为“厌恶比恐惧具有更强的记忆增强效应”提供了高时间分辨率的脑活动层面的证据, 从而进一步揭示了负性情绪增强记忆的认知机制。     

东莨菪碱对大鼠空间参考记忆和工作记忆的不同影响

观察东莨菪碱对空间参考记忆和空间工作记忆的编码、保持和提取过程的作用。应用Morris水迷宫实验测定大鼠的空间参考记忆和空间工作记忆,分别在训练的不同阶段腹腔注射东莨菪碱（1mg/kg）和相同容量的生理盐水,比较各东莨菪碱组和生理盐水组之间游泳潜伏期、路径长度、轨迹和游泳速度的差异。结果发现：与注射生理盐水相比,在训练前和探测实验前注射东莨菪碱的大鼠在探测实验中对目标象限不表现出空间偏爱,说明东莨菪碱干扰参考记忆的信息编码和提取过程;而在训练结束后注射东莨菪碱的大鼠探测实验的结果与生理盐水组相比没有显著差异,说明东莨菪碱对参考记忆的保持过程没有影响。在工作记忆实验中,无论第一次测试前、第一次测试后和第2次测试前注射东莨菪碱,均造成大鼠游泳潜伏期延长,说明东莨菪碱干扰工作记忆的编码、保持和提取过程。研究提示M受体在空间工作记忆和参考记忆中发挥不同作用     

远期恐惧记忆再巩固更新机制的线索选择性特点

已有动物和人类研究均表明, 通过记忆的再巩固更新机制能有效削弱新形成的条件性恐惧记忆(1天), 并且存在线索选择性特点。然而创伤后应激障碍(PTSD)往往在形成相当一段时间后才能得到治疗, 且现实生活中人们通常一次习得对多个线索的恐惧。因此找到针对多线索创伤记忆的有效治疗方法显得尤为重要。目前未有人研究远期恐惧记忆的再巩固更新机制是否存在线索选择性特点。为探究远期恐惧记忆(>7天)的再巩固更新机制是否同样存在线索选择性特点, 本研究采用被试内实验设计, 以皮肤电作为恐惧反应指标, 多个线索作为条件刺激进行恐惧习得, 习得14天后给被试单独呈现一个线索进行恐惧记忆提取, 10分钟后进行消退训练, 24小时后对不同线索进行自发恢复测试。结果显示：未提取线索的自发恢复程度显著高于提取线索。说明远期记忆(14天)的再巩固更新机制同样存在线索选择性特点, 并确认了提取消退作为一种行为手段对远期恐惧记忆再巩固进行干预的有效性, 对临床干预具有一定指导意义。     

Doubts about double dissociations between short- and long-term memory

Historically, psychologists and neuroscientists have distinguished between processes supporting memory for events across retention delays of several seconds (short-term memory, STM), and those supporting memory for events across longer retention delays of minutes or more (long-term memory, LTM). Dissociations reported in some neuropsychological studies have contributed to a popular view that there must be neurally distinct memory stores that differentially support STM and LTM. In this article, we review evidence from recent studies regarding dissociations between STM and LTM. We suggest that the evidence reveals problems with claims of selective STM or LTM impairments, which in turn questions whether theories of memory need to propose neurally distinct stores for short- and long-term retention. We consider alternative ways to explain the neural mechanisms of memory across different retention intervals.     

Interaction between amount and pattern of training in the induction of intermediate- and long-term memory for sensitization in aplysia

In Aplysia, three distinct phases of memory for sensitization can be dissociated based on their temporal and molecular features. A single training trial induces short-term memory (STM, lasting <30 min), whereas five trials delivered at 15-min intervals induces both intermediate-term memory (ITM, lasting >90 min) and long-term memory (LTM, lasting >24 h). Here, we explore the interaction of amount and pattern of training in establishing ITM and LTM by examining memory for sensitization after different numbers of trials (each trial = one tail shock) and different patterns of training (massed vs. spaced). Under spaced training patterns, two trials produced STM exclusively, whereas four or five trials each produced both ITM and LTM. Three spaced trials failed to induce LTM but did produce an early decaying form of ITM (E-ITM) that was significantly shorter and weaker in magnitude than the late-decaying ITM (L-ITM) observed after four to five trials. In addition, E-ITM was induced after three trials with both massed and spaced patterns of training. However, L-ITM and LTM after four to five trials require spaced training: Four or five massed trials failed to induce LTM and produced only E-ITM. Collectively, our results indicate that in addition to three identified phases of memory for sensitization—STM, ITM, and LTM—a unique temporal profile of memory, E-ITM, is revealed by varying either the amount or pattern of training.     

Cooling blocks ITM and LTM formation and preserves memory

In Lymnaea aerial respiratory behaviour can be operantly conditioned; snails learn not to perform this behaviour. Depending on the training procedure used, snails are competent to form either intermediate-term (ITM; lasting 1-3 h) or long-term (LTM; >4 h) memory. We found that cooling the snails for 1 h immediately after training was sufficient to block either ITM or LTM. Cooling snails for a similar period 10 or 15 min after cessation of training, failed to block ITM and LTM formation, respectively. Finally, we employed the cooling technique to extend both ITM and LTM. That is, cooling could prevent forgetting. Cooling extended LTM that normally persisted for 2 days to at least 8 days. These data are consistent with the hypothesis that forgetting is due to the learning and remembering of interfering events, and thus is an active process.     

Enhancement of long-term memory retention by Colostrinin in one-day-old chicks trained on a weak passive avoidance learning paradigm

Colostrinin (CLN) is a biologically active proline-rich polypeptide which has therapeutic potential for the alleviation of memory deficits in age-related dementias in a number of human conditions, particularly Alzheimer's disease. To examine the efficacy of CLN in other species, day-old domestic chicks were used as a model system to study its effects on retention of memory for a single one-trial learning paradigm--avoidance of a bitter-tasting substance (methylanthranilate, MeA). Birds were presented with a bead coated with either a dilute (10%) solution of MeA or a bead coated with 100% MeA. Those trained on 100% MeA avoided pecking at a similar but dry bead 24 h later, thereby demonstrating long-term memory whereas chicks trained on the 10% solution pecked the bead at 24 h, indicating lack of long term memory for the task. However, when CLN was injected (i.c.) into a region known to be important in memory formation, the mesopallium intermediomediale (IMM), prior to training with 10% MeA, chicks exhibited strong memory retention at 24 h, similar to those trained on 100% MeA. Control chicks trained on 10% MeA but injected i.c. with a 10% saline solution did not show improvement in memory retention. Intraperitoneal (i.p.) injections of CLN were as effective as the i.c. route. These data extend the known efficacy of CLN from mammals demonstrating its widespread efficacy as a cognitive enhancer.     

一日龄小鸡的不同记忆阶段中Jun样蛋白在脑内HV和LPO的表达

以一日龄小鸡为研究对象,采用一次性动回避反应试验和免疫组织化学结合的方法,选择六个时间点对Ｊｕｎ样蛋白在小鸡左右侧脑内ＨＶ和ＬＰＯ两部位的表进行了探讨。     

Endogenous BDNF is required for long-term memory formation in the rat parietal cortex

Information storage in the brain is a temporally graded process involving different memory phases as well as different structures in the mammalian brain. Cortical plasticity seems to be essential to store stable long-term memories, although little information is available at the moment regarding molecular and cellular events supporting memory consolidation in the neocortex. Brain-derived neurotrophic factor (BDNF) modulates both short-term synaptic function and activity-dependent synaptic plasticity in hippocampal and cortical neurons. We have recently demonstrated that endogenous BDNF in the hippocampus is involved in memory formation. Here we examined the role of BDNF in the parietal cortex (PCx) in short-term (STM) and long-term memory (LTM) formation of a one-trial fear-motivated learning task in rats. Bilateral infusions of function-blocking anti-BDNF antibody into the PCx impaired both STM and LTM retention scores and decreased the phosphorylation state of cAMP response element-binding protein (CREB). In contrast, intracortical administration of recombinant human BDNF facilitated LTM and increased CREB activation. Moreover, inhibitory avoidance training is associated with a rapid and transient increase in phospho-CREB/total CREB ratio in the PCx. Thus, our results indicate that endogenous BDNF is required for both STM and LTM formation of inhibitory avoidance learning, possibly involving CREB activation-dependent mechanisms. The present data support the idea that early sensory areas constitute important components of the networks subserving memory formation and that information processing in neocortex plays an important role in memory formation.     

Get the gist? The effects of processing depth on false recognition in short-term and long-term memory

Gist-based processing has been proposed to account for robust false memories in the converging-associates task. The deep-encoding processes known to enhance verbatim memory also strengthen gist memory and increase distortions of long-term memory (LTM). Recent research has demonstrated that compelling false memory illusions are relatively delay-invariant, also occurring under canonical short-term memory (STM) conditions. To investigate the contributions of gist to false memory at short and long delays, processing depth was manipulated as participants encoded lists of four semantically related words and were probed immediately, following a filled 3- to 4-s retention interval, or approximately 20 min later, in a surprise recognition test. In two experiments, the encoding manipulation dissociated STM and LTM on the frequency, but not the phenomenology, of false memory. Deep encoding at STM increases false recognition rates at LTM, but confidence ratings and remember/know judgments are similar across delays and do not differ as a function of processing depth. These results suggest that some shared and some unique processes underlie false memory illusions at short and long delays.     

Components of visual memory

Visual recognition memory for a sequence of non-verbalized patterns is shown to have a large and clearly defined recency effect. This recency effect occurs with random list lengths and therefore cannot be due to differential processing of the end items. The effect is completely removed by just 3 s of mental arithmetic but survives for at least 10 s over unfilled intervals. Recognition memory for patterns at other serial positions is slower, less accurate, and shows no primacy effect; performance at these earlier serial positions is dependent upon the time for which patterns are initially presented, but is unaffected by the duration of the retention interval, mental arithmetic, and the time between patterns on initial presentation. These findings provide evidence that visual memory has two components that are closely analogous to the short-term (STM) and long-term (LTM) components of verbal memory. Visual STM, here called visualization, has a capacity of one pattern, cannot be activated LTM, and does not seem to be the gateway to LTM.