Recovery of memory after amnesia induced by electroconvulsive shock

Electroconvulsive shock given to rats immediately after one-trial avoidance learning produced a significant amnesic effect 24 hours later; this amnesia had largely disappeared in further retention tests 48 and 72 hours after treatment. This result puts in question a basic assumption implicit in most memory consolidation studies that such amnesic effects will be permanent.     

Memory impairment after subcutaneous injection of acetoxycycloheximide

Subcutaneous injection of 240 micrograms of acetoxycycloheximide in mice rapidly produces marked inhibition of cerebral protein synthesis. Treated mice were trained to escape shock by choosing the lighted limb of a T-maze. When trained five or more minutes after injection, they had a normal capacity to learn. They remembered normally 3 hours after training, but 6 hours after training they had markedly impaired retention. Amnesia persisted thereafter. Injections immediately after training had a less marked but significant amnesic effect. These studies suggest that protein synthesis is not necessary for learning or for memory for 3 hours after training but that it is required for long-term memory. The protein synthesis which appears to be necessary for long-term e3memory occurs during training, or within minutes after training, or both.     

Amnesia produced by spreading depression and ECS: evidence for time-dependent memory trace localization

Rats were given electroconvulsive shock and bilateral cortical spreading depression, either alone or in combination, at various times after a single passive avoidance training trial. Assessment of retention deficits, 24 hours after training, revealed a U-shaped amnesic function for cortical spreading depression as compared with the short linear function consistently obtained with electroconvulsive shock in this situation. Induction of cortical spreading depression immediately after training resulted in an extension of the amnesic gradient produced by electroconvulsive shock, presumably by disruption of the subcortically confined memory trace. In addition to indicating a stibcortical locus of action for the amnesic effects of electroconvulsive shock, these results are interpreted as favoring a hypothesis of time-dependent memory trace localization in short-term memory processing, which involves an initial subcortical localization of the trace followed by a phase involving either direct or indlirect cortical participation in a mulltistage memory fixation process.     

Memory disruption by electrical stimulation of substantia nigra, pars compacta

Electrical stimulation of the substantia nigra, pars compacta, of albino rats while they were learning a simple foot shock task of withdrawal and response suppression disrupted retention of that task 24 hours after original learning. Stimulation in the reticular zone of the substantia nigra was without effect on retention performance. Stimulation through electrodes in the medial lemniscus, red nucleus, or brainstem regions surrounding the substantia nigra, pars compacta, was also ineffective. Original learning performance, measured as time to criterion, was unimpaired by the stimulation. Posttrial stimulation in the substantia nigra, pars compacta, but not in adjacent structures, also disrupted retention performance.     

Time-dependent processes in memory storage

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.     

“投入量假设”在词汇附带习得中的应用研究

"词汇附带习得"是指非刻意的学习,或在学习者的主要目的不在词汇学习而是在完成其他学习任务的情况下无意识习得了词汇。"投入量假设"是Laufer和Hu lstijn提出的,并以此作为衡量学习任务对词汇附带习得作用的标准。不同的学习任务对词汇习得的不同影响是由学习者对词汇进行不同的认知加工程度造成的。"投入量假设"虽对促进二语词汇附带习得的教学有重要的指导作用,但其假设的量化指标需进一步修正。     

Acquisition of Key-Pecking via Autoshaping as a Function of Prior Experience: "Learned Laziness"?

A group of pigeons that had previously received noncontingent food delivery acquired the key-peck response (in autoshape training) more slowly than did a naive control group; key-peck acquisition was most rapid for a group given operant treadle-press training in the initial phase.     

北海道黄杨扦插繁殖的研究

北海道黄杨当年生枝条,用不同外源激素、不同时间和不同浓度处理后插入蛭石中培养。试验结果表明：当年生枝条生根率优于带一段老枝的当年生枝条生根率,扦插30d后,生根率达84．71％。IBA和NAA对促进北海道黄杨生根均有一定效果,但生根率IBA高于NAA,使用IBA和NAA进行高浓度短时间处理时,以浓度为800mg/L时效果最好,经IBA处理后的插条,平均根数为25．67条,经NAA处理后的插条平均根数为9．01条。使用IBA和NAA进行低浓度长时间处理时,生根效果随激素浓度的升高而增加,IBA以浓度为160mg/L处理14-18h效果最好,平均根数为49．88条;NAA以浓度为160mg/L处理10－14h效果最好,平均根数为14．33条。     

“任务驱动”在园林AutoCAD教学中的实践

将"任务驱动"教学方法运用到园林AutoCAD课程,改传统知识"灌输式"为"以任务为主线、教师为主导、学生为主体"的任务驱动模式,学生由被动接受者转变成主动探究者,学做一体,真正体现了高职教育让学生掌握技能的教学目标.     

疏果灵在柠檬上的应用效果研究

[目的]研究疏果灵对柠檬的疏果效应,为其在柠檬疏果上的应用提供理论依据。[方法]以不同浓度的疏果灵处理柠檬幼果,调查不同时期不同处理的疏果效应。[结果]柠檬于4月中旬出现了生理落果高峰期。在此期间对照组的落果量大大低于喷施疏果灵的3个处理;而在这3个喷施不同浓度的疏果灵处理中,200倍液处理的落果数最多,持续落果时间最短,疏果效应最好。[结论]疏果灵对柠檬有较好的疏果效应,以200倍稀释液效果最佳。     

Effect of electroconvulsive shock on an extinguished "fear" response

To test Gellhorn's hypothesis that electroconvulsive shock reinstates extinguished responses, a conditioned "anxiety" response was established and then extinguished in rats. A series of treatments did not restore the extinguished "anxiety" response; in fact, control animals showed appreciable spontaneous recovery of the "anxiety" response while treated animals did not.     

“旱地龙”对甘蔗伸长初期抗旱生理指标的影响

[目的]探讨干旱胁迫条件下,在甘蔗生产中喷施"旱地龙"的最佳时期及浓度。[方法]采用桶栽试验,设喷施2、46、g/L"旱地龙"(A、B、C)和清水(D)4个处理。[结果]从2007年11月20日至12月10日,喷施"旱地龙"+1叶POD活性均高于D处理,其中处理B+1叶POD活性比其他处理高,与D差异极显著;B、C处理的+1叶PPO活性高于D处理,A处理低于D处理;D处理的+3叶PRO含量不断下降,B、C、A处理的PRO含量先升后降,且下降的幅度小于D处理;B处理的MDA含量极显著低于D处理。PPO酶活性的提高与PRO含量的提高呈极显著正相关(相关系数为0.686 5),MDA含量与POD活性呈负相关(相关系数为-0.011 3)。[结论]4 g/L"旱地龙"可作为甘蔗伸长初期的抗旱保护剂。     

Retrograde amnesia: production of skseletal but not cardiac response gradient by electroconvulsive shock

Rats given a single electroconvulsive shock immediately after but not 60 seconds after an aversive conditioning trial exhibited behavioral retention deficits 24 hours later in a one-trial passive avoidance task. In contrast to these differential performance deficits, similar heart-rate changes, indicative of fear retention, were seen in punished animals irrespective of the time of delivery of the shock. These data suggest retention of a generalized fear to the training experience that was not revealed by the behavioral measure. The potential usefulness of concomitant behavioral and physiological response assessment in consolidation research is discussed.     

东方百合“Sorbonne”花期化学调控技术研究

利用不同浓度的赤霉素(GA3)、激动素(KT)、乙烯利(CEPA)及其混合液分别处理东方百合“Sor-bonne”种球,结果表明所有处理均能不同程度地影响“Sorbonne”的花期,其中GA3100 KT100 CEPA200处理效果最为显著,其次为GA3300 KT50处理。利用植物生长调节剂处理东方百合,其鲜切花品质与对照无明显差异。赤霉素与激动素单独处理时用25%丙酮代替清水作为溶剂对提高东方百合切花整齐度具有促进效果。     

红中牌生物有机肥在棉花上的应用效果

田间试验结果表明,棉花施用红中牌生物有机肥比对照处理(当地施肥模式)的籽棉产量明显增加,增产幅度为2.32%~10.43%,纯收入增长率为6.73%~24.59%。在施用红中肥的3个处理中,单纯施红中肥的方式比施“红中肥+化肥”的方式效果更好。     

Multiphasic retention deficits at periodic intervals after passive-avoidance learning

Aftetr one-trial passive-avoidance training, indepelenet groups of rats tested promptly after training or at successive 6-hour intervals displayed a repetitive pattern of high then low retention scores. These results suggest that some physiological rhythm may interact with retention performance.     

Amnesic effects of small bilateral brain puncture in the mouse

A small acute brain puncture produced retrograde amnesia in a passive avoidance learning situation in mice. If injury to the hippocampus was inflicted either immediately, 1 hour after the learning, or 1 hour before the learning, the animals showed a retention deficit; the degree of this deficit was related to the time interval. No effect of this injury was observed on retest performance when the animals were treated as long as 6 hours before or after the learning trial.     

"团队协助学习法"在教学中的实践与运用

对华南热带农业大学公共关系学专业近年的教学改革进行总结,提炼出适合公共关系学专业特点的“团队协作学习法”。将“团队协作学习法”具体做法进行研究、归纳、总结及运用,从具体的教学实践看,“团队协作学习法”在教学中取得了一定的成效,对教学过程具有积极的意义。     

Leaf infections: siderochromes (natural polyhydroamates) mimic the "green island" effect

Topical application of as little as 5x10(-12) moles of pure siderochromes (polyhydroxamate iron-transport compounds from bacteria and fungi) onto detached bean leaves causes spots of chlorophyll retention that are surrounded by chlorotic halos. These spots appear similar to "green islands" that are caused by certain fungal infections on leaves and are somewhat similar to zones where senescence is delayed by cytokinin.     

略论‘以人为本”的高校教学观

教学观对教学具有直接指导意义,本文从高校工作为教学服务、师生互动、调动学生学习主动性和培养全面发展人才的四个方向阐述了“以人为本”的高校教学观