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1.
采用双任务范式使被试将工作记忆信息保存在工作记忆当中并完成选择性注意任务,结果发现:视觉空间工作记忆负荷不能使熟悉面孔的干扰效应消失,语义工作记忆负荷使熟悉面孔的干扰效应在高知觉负荷条件下消失.因此,熟悉面孔在高知觉负荷条件下可能是以语义的方式存储在工作记忆当中,在低知觉负荷条件下可能是同时存储在视觉空间工作记忆和语义工作记忆中. 相似文献
2.
Although primary CD8 responses to acute infections are independent of CD4 help, it is unknown whether a similar situation applies to secondary responses. We show that depletion of CD4 cells during the recall response has minimal effect, whereas depletion during the priming phase leads to reduced responses by memory CD8 cells to reinfection. Memory CD8 cells generated in CD4+/+ mice responded normally when transferred into CD4-/- hosts, whereas memory CD8 cells generated in CD4-/- mice mounted defective recall responses in CD4+/+ adoptive hosts. These results demonstrate a previously undescribed role for CD4 help in the development of functional CD8 memory. 相似文献
3.
4.
Using functional magnetic resonance imaging, we investigated the mechanism by which cholinergic enhancement improves working memory. We studied the effect of the cholinesterase inhibitor physostigmine on subcomponents of this complex function. Cholinergic enhancement increased the selectivity of neural responses in extrastriate cortices during visual working memory, particularly during encoding. It also increased the participation of ventral extrastriate cortex during memory maintenance and decreased the participation of anterior prefrontal cortex. These results indicate that cholinergic enhancement improves memory performance by augmenting the selectivity of perceptual processing during encoding, thereby simplifying processing demands during memory maintenance and reducing the need for prefrontal participation. 相似文献
5.
Time-dependent processes in memory storage 总被引：33，自引：0，他引：33
J L McGaugh 《Science (New York, N.Y.)》1966,153(742):1351-1358
These observations indicate that the long-lasting trace of an experience is not completely fixed, consolidated, or coded at the time of the experience. Consolidation requires time, and under at least some circumstances the processes of consolidation appear to be susceptible to a variety of influences- both facilitating and impairing- several hours after the experience. There must be, it seems, more than one kind of memory trace process (31). If permanent memory traces consolidate slowly over time, then other processes must provide a temporary basis for memory while consolidation is occurring. The evidence clearly indicates that trial-to-trial improvement, or learning, in animals cannot be based completely on permanent memory storage. Amnesia can be produced by electroshock and drugs even if the animals are given the treatment long after they have demonstrated "learning" of the task. Of particular interest is the finding that retention of the inhibitory avoidance response increases with time. In a sense this should be expected, for it has long been known (and ignored) that, within limits, learning is facilitated by increasing the interval between repeated trials (7, 30). Our result may be the simplest case of such an effect. Since the improvement in retention with time seemed not to be due solely to consolidation (as indicated by electroshock effects), it would seem that the "distribution of practice" effect, as it is typically designated, may be due in part to a time-dependent temporary memory storage process. In our work with animals we have found no analog of human immediate memory such as that required for repeating digits (or finishing sentences). Animals tested immediately on the task described above after a trial typically showed no evidence of memory. It could be that the poor performance is due to excessive fright, but the "distribution of practice effect" is also typically observed in learning experiments in which food reward is used rather than shock avoidance. Since the retention tasks require the animals to change their behavior in some way, it could well be that the growth of retention over the first few minutes after a trial is due to time dependent processes involved in the organization of processes necessary for changing behavior, in addition to those involved in temporary storage and retrieval. It is worth pointing out that there is evidence of an analogous process in human memory (32). A complex picture of memory storage is emerging. There may be three memory trace systems: one for immediate memory (and not studied in our laboratory); one for short-term memory which develops within a few seconds or minutes and lasts for several hours; and one which consolidates slowly and is relatively permanent. The nature of the durability of the longterm memory trace (that is, the nature and basis of forgetting) is a separate but important issue. There is increasing evidence and speculation (20, 21, 33) that memory storage requires a "tritrace" system, and our findings are at least consistent with such a view. If there are, as seems possible, at least three kinds of traces involved in memory storage, how are they related? Is permanent memory produced by activity of temporary traces (31), or are the trace systems relatively independent? Although available findings do not provide an answer to this question, there does seem to be increasing evidence that the systems are independent. Acquisition can occur, as we have seen, without permanent consolidation, and both short-term and long-term memory increase with time. All this evidence suggests (but obviously does not prove) that each experience triggers activity in each memory system. Each repeated training trial may, according to this view, potentiate short-term processes underlying acquisition while simultaneously enhancing independent underlying long-term consolidation. Obviously, acceptance of these conclusions will require additional research. If this view is substantially correct, it seems clear that any search for the engram or the basis of memory is not going to be successful. Recognition of the possibility that several independent processes may be involved at different stages of memory may help to organize the search. A careful examination of the time course of retention and memory trace consolidation, as well as examination of the bases of the effects of memory-impairing and memory-facilitating treatments, may help to guide the search. It is clear that a complete theory of memory storage must eventually provide an understanding of time-dependent processes in memory. In 1930 Lashley wrote (2), "The facts of both psychology and neurology show a degree of plasticity, of organization, and of adaptation and behavior which is far beyond any present possibility of explanation." Although this conclusion is still valid, the current surge of interest in memory storage offers hope that this conclusion may soon need to be modified. 相似文献
6.
通过事件相关电位(ERP)技术,让被试分别在金钱启动和中性启动条件下,用"触及自尊符合词"和"触及自尊不符合词"对"自我"和"正性他人"进行符合与否的评价,以此来探讨金钱启动对被试外显自尊影响的脑内时程动态变化.结果发现:在中性启动条件下,触及自尊不符词的自我评价比触及自尊不符词的他人评价诱发了更大的P300成分,这与前人的研究一致;相反,在金钱启动条件下,自我评价与他人评价之间的差异消失了.认为金钱启动增强了个体的自尊水平,对自尊产生了一种补偿作用,并且,这种补偿作用有可能与情绪有关. 相似文献
7.
Simulation of paleocortex performs hierarchical clustering 总被引：7，自引：0，他引：7
Simulations were performed of layers I and II of olfactory paleocortex, as connected to its primary input structure, olfactory bulb. Induction of synaptic long-term potentiation by means of repetitive sampling of inputs caused the simulation to organize encodings of learned cues into a hierarchical memory that uncovered statistical relationships in the cue environment, corresponding to the performance of hierarchical clustering by the biological network. Simplification led to characterization of those parts of the network responsible for the mechanism, resulting in a novel, efficient algorithm for hierarchical clustering. The hypothesis is put forward that these corticobulbar networks and circuitry of similar design in other brain regions contain computational elements sufficient to construct perceptual hierarchies for use in recognizing environmental cues. 相似文献
8.
《农业科学学报》2017,(12)
Anticipated more frequent extreme events due to changes in global climatic variability requires adaptation of crop species to multi-occurrence abiotic stresses hereby sustaining the food security. Priming, by pre-exposure of plants to an eliciting factor, enables plants to be more tolerant to later biotic or abiotic stress events. Priming induced "stress memory" exists in both present generation and the offspring. Thus, priming is suggested to be a promising strategy for plants to cope with the abiotic stresses under global change scenarios. In this review, the underlying physiological and molecular mechanisms of priming induced enhancement of stress tolerance to the major abiotic stresses of drought and waterlogging, and high and low temperature in crop plants were discussed, and the potential to utilize the priming effect for sustaining crop productivity in future climates was also suggested. 相似文献
9.
Jordan MB Mills DM Kappler J Marrack P Cambier JC 《Science (New York, N.Y.)》2004,304(5678):1808-1810
Exposure of na?ve B cells to the cytokine interleukin-4 (IL-4) and/or antigen leads to a state of "priming," in which subsequent aggregation of major histocompatibility complex class II molecules induces the mobilization of calcium ions and cell proliferation. However, it is not clear how critical this priming is for immune responses or how it is normally induced in vivo. Injection of mice with the commonly used adjuvant alum led to priming of splenic B cells and to the accumulation in the spleen of a previously unknown population of IL-4-producing, Gr1+ cells. These cells and IL-4 were both required for in vivo priming and expansion of antigen-specific B cells, as well as for optimal production of antibody. These studies reveal a key role for a previously unknown accessory myeloid cell population in the generation of humoral immune responses. 相似文献
10.
Nakazawa K Quirk MC Chitwood RA Watanabe M Yeckel MF Sun LD Kato A Carr CA Johnston D Wilson MA Tonegawa S 《Science (New York, N.Y.)》2002,297(5579):211-218
Pattern completion, the ability to retrieve complete memories on the basis of incomplete sets of cues, is a crucial function of biological memory systems. The extensive recurrent connectivity of the CA3 area of hippocampus has led to suggestions that it might provide this function. We have tested this hypothesis by generating and analyzing a genetically engineered mouse strain in which the N-methyl-D-asparate (NMDA) receptor gene is ablated specifically in the CA3 pyramidal cells of adult mice. The mutant mice normally acquired and retrieved spatial reference memory in the Morris water maze, but they were impaired in retrieving this memory when presented with a fraction of the original cues. Similarly, hippocampal CA1 pyramidal cells in mutant mice displayed normal place-related activity in a full-cue environment but showed a reduction in activity upon partial cue removal. These results provide direct evidence for CA3 NMDA receptor involvement in associative memory recall. 相似文献
11.
Perceiving real-world scenes 总被引：9，自引：0，他引：9
I Biederman 《Science (New York, N.Y.)》1972,177(43):77-80
When a briefly presented real-world scene was jumbled, the accuracy of identifying a single, cued object was less than that when the scene was coherent. Jumbling remained an effective variable even when the subject knew where to look and what to look for. Thus an object's meaningful context may affect the course of perceptual recognition and not just peripheral scanning or memory. 相似文献
12.
郭炎林 《上海交通大学学报(农业科学版)》2014,(6):63-66
运用时间知觉与时间估计理论，探讨操作与控制田径运动技能中时距、时序、时间估计对节奏的影响。通过节奏构成的要素，阐述了动作技能中的节奏是一种组织结构，是动作技能操作过程中的一种组织表现。时距知觉可以直接控制节奏的快慢和影响动作技能的时间结构从而改变节秦；时序知觉的启动效应在个体动作技能的学习与控制过程中影向着完成的质量，并具有不断发展变化和个性特点；准确的时间估计是动作技能操作中时间信息的反馈与记忆或经验的一种对比，其对完成长距离径赛项目中的节奏控制有着极为重要作用。 相似文献
13.
Bidirectional signaling between neocortex and limbic cortex has been hypothesized to contribute to the retrieval of long-term memory. We tested this hypothesis by comparing the time courses of perceptual and memory-retrieval signals in two neighboring areas in temporal cortex, area TE (TE) and perirhinal cortex (PRh), while monkeys were performing a visual pair-association task. Perceptual signal reached TE before PRh, confirming its forward propagation. In contrast, memory-retrieval signal appeared earlier in PRh, and TE neurons were then gradually recruited to represent the sought target. A reasonable interpretation of this finding is that the rich backward fiber projections from PRh to TE may underlie the activation of TE neurons that represent a visual object retrieved from long-term memory. 相似文献
14.
Memory in mice analyzed with antibiotics. Antibiotics are useful to study stages of memory and to indicate molecular events which sustain memory 总被引：11，自引：0，他引：11
It is apparent that antibiotics are useful in differentiating different stages in the formation of memory. Puromycin gave the first indication that very early memory can be established and survive, for a short period at least, in spite of inhibition of protein synthesis (12). Injection of actinomycin D indicates that RNA synthesis is not essential during this early stage (13). The duration of this early period seems to vary with the inhibiting agent; with puromycin memory was notably degraded in less than an hour, but with actinomycin D or with acetoxycycloheximide it persisted for several hours or more. The fixation or consolidation of memory involves whatever processes give permanence to memory. These processes are disrupted when electroconvulsive shock is administered shortly after a learning experience, presumably because of the interference with organized patterns of neuronal electrical activity. Memory acquired in the presence of antibiotics appears to proceed to a stage beyond that based purely on electrical activity because the memory persists beyond the period usually reported as sensitive to electroconvulsive shock. Further work should show whether this stage is truly insensitive to electroconvulsive shock. Memory acquired in the presence of puromycin does not seem to achieve any durable consolidation. In contrast, memory acquired in the presence of or immediately before injection of acetoxycycloheximide does appear to initiate the later stages of consolidation, as permanent memory. reappears some days after the initial stages have become ineffective in controlling performance. Finally, puromycin has provided evidence of the enlarged area of the neocortex which participates as memory matures. Puromycin also indicates the time required for this maturation process. Since antibiotics have also been useful in studying learning and memory in goldfish (14), this approach seems to have general applicability in defining various stages in the process of memory formation. The initial purpose of these investigations was to determine the molecular basis of the "memory trace" This goal still remains distant, although there are some indications that protein synthesizing systems are involved. This objective, though of enormous interest, is to be regarded as only a necessary first step. Whether new proteins or some other molecules cause the changes in synapses thought to underlie memory, this knowledge of itself will contribute only a beginning to our understanding of the events which account for the functioning of the brain. A determination of the composition of computer components would provide very little information towards unraveling their function. As the experiments proceeded, however, information of a more general nature was being obtained. The identification of different stages of consolidation show how injections of antibiotics can supplement electroconvulsive shock as a way of disrupting the establishment of memory and how it can supplement ablation in destroying memory already laid down in a permanent mode. Applied to larger animals the localization of various regions sensitive or insensitive to the action of the drugs should become more definitive. We hope that such experiments will contribute increasingly to the general problem of brain function. 相似文献
15.
Mechanisms of memory 总被引：17，自引：0，他引：17
L R Squire 《Science (New York, N.Y.)》1986,232(4758):1612-1619
Recent studies of animals with complex nervous systems, including humans and other primates, have improved our understanding of how the brain accomplishes learning and memory. Major themes of recent work include the locus of memory storage, the taxonomy of memory, the distinction between declarative and procedural knowledge, and the question of how memory changes with time, that is, the concepts of forgetting and consolidation. An important recent advance is the development of an animal model of human amnesia in the monkey. The animal model, together with newly available neuropathological information from a well-studied human patient, has permitted the identification of brain structures and connections involved in memory functions. 相似文献
16.
Allan RS Smith CM Belz GT van Lint AL Wakim LM Heath WR Carbone FR 《Science (New York, N.Y.)》2003,301(5641):1925-1928
The classical paradigm for dendritic cell function derives from the study of Langerhans cells, which predominate within skin epidermis. After an encounter with foreign agents, Langerhans cells are thought to migrate to draining lymph nodes, where they initiate T cell priming. Contrary to this, we show here that infection of murine epidermis by herpes simplex virus did not result in the priming of virus-specific cytotoxic T lymphocytes by Langerhans cells. Rather, the priming response required a distinct CD8alpha+ dendritic cell subset. Thus, the traditional view of Langerhans cells in epidermal immunity needs to be revisited to accommodate a requirement for other dendritic cells in this response. 相似文献
17.
鲜萝卜颗粒引发老化大豆种子,能明显提高种子萌发率和活力;减少电解质和氨基酸外渗。种子引发后“不回干”与“回干”两种处理的萌发率分别为94.5%和68.5%,是对照的2.2倍和1.6倍;活力指数为6.78和2.30,是对照的9.7倍和3.3倍;电解质外渗为34.0 μS/cm和38.9 μS/cm,占对照59.3%和67.9%;而氨基酸外渗为6.72 μg/g和10.89 μg/g,占对照22.7%和10.89%,各指标的差异达显著水平。结果显示:引发效果是“不回干”的好于“回干”的,这可为老化种子引发方法提供参考。 相似文献
18.
Schemas and memory consolidation 总被引：1，自引：0，他引：1
Tse D Langston RF Kakeyama M Bethus I Spooner PA Wood ER Witter MP Morris RG 《Science (New York, N.Y.)》2007,316(5821):76-82
Memory encoding occurs rapidly, but the consolidation of memory in the neocortex has long been held to be a more gradual process. We now report, however, that systems consolidation can occur extremely quickly if an associative "schema" into which new information is incorporated has previously been created. In experiments using a hippocampal-dependent paired-associate task for rats, the memory of flavor-place associations became persistent over time as a putative neocortical schema gradually developed. New traces, trained for only one trial, then became assimilated and rapidly hippocampal-independent. Schemas also played a causal role in the creation of lasting associative memory representations during one-trial learning. The concept of neocortical schemas may unite psychological accounts of knowledge structures with neurobiological theories of systems memory consolidation. 相似文献
19.
土壤氮激发效应的探讨 总被引：8，自引：1，他引：7
结合近年来利用同位素示踪技术进行的氮素研究,比较系统地探讨了土壤氮素的激发效应及其影响因子。通过土壤和肥料的C/N值、土壤水分、肥料种类及不同耕作措施等因子对土壤氮素激发效应影响的探讨,指出在田间条件下,土壤氮的激发效应实际上是土壤氮素肥力在动态过程中的一项综合指标,它反映了土壤在某一特定的耕作栽培系统内氮素的盈亏和平衡状况。它不仅受施肥的影响,而且受这一系统的制约。 相似文献
20.
采收时间对烤烟致香物质含量和评吸质量的影响 总被引：1，自引：0，他引：1
采用大田试验研究了采收时间对不同部位烤烟(N icotiana tabacum L.)叶片主要致香物质含量和评吸质量的影响。结果表明,下部叶提前1周至常规采收、中部叶和上部叶推迟1周左右采收,烟叶中大部分致香物质含量较高,致香物质总量和类胡萝卜素类致香物质含量明显增加;烟叶评吸总分及香气质、香气量、余味得分较高,香气质量较好,适宜在生产上推广应用。 相似文献