Awake hippocampal sharp-wave ripples support spatial memory

The hippocampus is critical for spatial learning and memory. Hippocampal neurons in awake animals exhibit place field activity that encodes current location, as well as sharp-wave ripple (SWR) activity during which representations based on past experiences are often replayed. The relationship between these patterns of activity and the memory functions of the hippocampus is poorly understood. We interrupted awake SWRs in animals learning a spatial alternation task. We observed a specific learning and performance deficit that persisted throughout training. This deficit was associated with awake SWR activity, as SWR interruption left place field activity and post-experience SWR reactivation intact. These results provide a link between awake SWRs and hippocampal memory processes, which suggests that awake replay of memory-related information during SWRs supports learning and memory-guided decision-making.     

Extinction following intracranial reward: the effect of delay between acquisition and extinction

Rats trained to press a bar for intracranial reinforcement gave as many responses during extinction as did water-reinforced controls, when extinction came immediately after an acquisition session. However, the experimental animals gave fewer responses in extinction than water-reinforced animals when extinction was delayed for 1 hour after acquisition. The activity level of the experimental animals was high immediately after acquisition but declined markedly over the delay period, which suggests that resistance to extinction after intracranial reinforcement is primarily a function of activity level.     

Delayed alternation in hemicerebrectomized monkeys

Monkeys subjected to extensive unilateral brain extirpation learned a delayed alternation task, although their rates of learning were significantly lower than those of a control group of normal animals. Visual field defects did not seem to account for the deficit.     

Cretinism in rats: enduring behavioral deficit induced by tricyanoaminopropene

Rats reared on diets containing tricyanoaminopropene, the antithyroid compound that stimulates RNA synthesis, showed a deficit in performance on automated closed-field maze tests many weeks after discontinuation of the drug. The rats were also tested while still receiving the drug, and performance deficits were indicated in tests of Y-maze reversal and manual closed-field maze performance; rats treated with the drug and with thiouracil behaved in a highly similar fashion on several tasks. No evidence of facilitation by tricyanoaminopropene appeared in any of the eight learning situations used. Exposure to tricyanoaminopropene before and after birth, at doses sufficient to produce anatomical cretinism, apparently induces an enduring behavioral deficit which is similar to that of neonatal thyroidectomy-induced cretinism in rats and which parallels the mental retardation associated with human cretinism.     

冷应激对海兰雏鸡胃肠道粘膜损伤的影响

本实验观察了不同的时间的低温饲养加浸水应激及浸水应激后不同时间对海兰雏鸡胃肠道粘膜损伤的情况。结果表明：即刻观察雏鸡在低于正常饲养温度５℃时加浸水应激后造成胃肠道充血现象并不严重;而浸水应激后不同时间却对雏鸡产生相对较强的影响,特别是冷应激后１～２ｈ胃肠道充血比较严重,与冷应激前比较差异显著（ｐ〈０．０５）。所以在生产过程中应避免产生冷应激,否则易诱发其他疾病的发生。     

调亏滴灌对土壤水盐分布与河套蜜瓜产量的影响

研究不同生育期调亏及亏缺程度对土壤水盐分布和河套蜜瓜产量的影响。采用田间滴灌试验,分别在蜜瓜伸蔓期和结果期进行20%、30%和40%灌水量亏缺处理。试验结果表明:充分灌溉处理(T1)的土壤剖面含水率随时间波动最为剧烈,伸蔓期和结果期亏缺处理的土壤剖面含水率平均极差分别比T1低48.5%和80%。各处理的土壤剖面盐渍度随时间均有增长趋势,T1的土壤剖面平均电导率在生育期前后的增幅为0.026ds/m,亏缺灌溉处理的增幅为0.073~0.098ds/m。伸蔓期和结果期亏缺处理的产量平均值分别比充分灌溉处理显著降低16.0%和20.5%,但2个时期亏缺处理的产量之间不存在显著性差异。伸蔓期亏缺处理的平均灌溉水利用效率比T1低11.6%,而结果期亏缺处理比T1高6.5%。在结果期亏缺处理中,进行30%灌水量亏缺的T7产量最高,并与伸蔓期各亏缺处理相对于T1的减产幅度相差不大,但灌水量比T1低25.0%,灌溉水利用效率比T1高9.0%。因此,为取得较好的节水效应和灌溉水利用效率,T7是滴灌条件下河套蜜瓜覆膜起垄种植的最佳选择。     

Long temporal gradient of retrograde amnesia for a well-discriminated stimulus

This experiment tested the general validity of recent findings that retrograde amnesia can be produced by electroconvulsive shock only if the shock is administered within 10 to 30 seconds after the learning trial. Precautions were taken to avoid confusion of other shock effects with retrograde amnesia. A temporal gradient of elec- troconvulsive shock-produced retrograde amnesia, extending up to at least 1 hour, for a well-discriminated stimulus, was demonstrated in mice in a one-trial learning passive avoidance situation.     

Prenatal exposure to carbon monoxide: learning and memory deficits

Exposing pregnant rats to carbon monoxide (150 parts per million) produced only minor reductions in the birth weights of the pups and gave no evidence of overt teratogenesis. However, behavioral evaluation of learning and memory processes in a two-way avoidance task suggested a functional deficit in the central nervous system of the exposed offspring. Multiple dependent measures and specific control groups confirmed that this deficit was independent of nonassociative or motivational alterations.     

Memory in mice analyzed with antibiotics. Antibiotics are useful to study stages of memory and to indicate molecular events which sustain memory

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.     

Visual attention in the tree shrew: an ablation study of the striate and extrastriate visual cortex

Removal of the striate area in tree shrews results in increased distractibility, which prevents the animals from learning to discriminate form when hue is an irrelevant and distracting cue. Removal of the extrastriate visual cortex results in the reciprocal deficit: an increase in perseveration manifested by an inability to shift attention when irrelevant dimensions are made relevant.     

Loss of hippocampal theta rhythm results in spatial memory deficit in the rat

Rats learned, using distal room cues, to run to a goal on an elevated, circular track starting from any position on the track. The goal was one of eight equidistant, recessed cups set around the track, the goal cup being distinguished from the others solely by its position in the room. After learning, electrolytic lesions were made in the medial septal nucleus eliminating hippocampal theta rhythm in some animals but not in others. Rats without theta rhythm were no longer able to perform the spatial task, whereas rats with undisturbed theta rhythm retrained normal performance. Although rats without theta rhythm could not find their way directly to the goal, they recognized its location when they came upon it by chance. This type of spatial deficit appears similar to that shown by hippocampally lesioned patient H.M. Subsequent tests demonstrated that rats deprived of theta rhythm before training could nevertheless learn the task.     

渗透胁迫下大白菜吸收转运~(45)Ca_(2 )的变化

在－０．３Ｐａ和－１．０ＰａＰＥＧ胁迫过程中,大白菜幼苗根系膜透性,ＴＴＣ还原能力和丙二醛含量的变化显示根受到的不同程度伤害．渗透胁迫处理下,根系对钙的吸收速率在［Ｃａ２＋］＞０．７５ｍｍｏｌ／Ｌ时明显受到抑制．根系对４５Ｃａ２＋的积累能力分别在－０．３ＰａＰＥＧ胁迫５ｈ和－１．０ＰａＰＥＧ胁迫３ｈ后受到抑制．而且大白菜各器官（根、茎、叶）对４５Ｃａ２＋的吸收、转运能力在渗透胁迫下发生不同程度下降．其中叶对渗透胁迫反映最敏感．胁迫条件下,叶片各部位４５Ｃａ２＋积累明显减少．其中叶缘反映最为敏感．     

Unsupervised natural experience rapidly alters invariant object representation in visual cortex

Object recognition is challenging because each object produces myriad retinal images. Responses of neurons from the inferior temporal cortex (IT) are selective to different objects, yet tolerant ("invariant") to changes in object position, scale, and pose. How does the brain construct this neuronal tolerance? We report a form of neuronal learning that suggests the underlying solution. Targeted alteration of the natural temporal contiguity of visual experience caused specific changes in IT position tolerance. This unsupervised temporal slowness learning (UTL) was substantial, increased with experience, and was significant in single IT neurons after just 1 hour. Together with previous theoretical work and human object perception experiments, we speculate that UTL may reflect the mechanism by which the visual stream builds and maintains tolerant object representations.     

Vascular lesions: possible pathogenetic basis of the generalized Shwartzman reaction

Evidence of vascular injury was found in rabbits after a single small dose of endotoxin from Escherichia coli. Eighty percent of the treated animals developed circulating endothelial cells, leukopenia, and thrombocytopenia, and 50 percent had aortic endothelial lesions as determined by electron microscopy. Prior anticoagulation with heparin did not prevent this response. No control animals showed these abnormalities.     

经后路椎弓根固定治疗胸腰椎骨折并脊髓损伤24例疗效分析

目的观察经后路椎弓根固定治疗胸腰椎骨折并脊髓损伤的疗效.方法所有患者在伤后6 h～10 d行后路切开复位、短节段椎弓根钉内固定术.本组全部病例术前、术后及随诊时均摄正侧位X片、CT或MR I扫描检查.结果经X片、CT检查,病椎高度恢复90%以上,伤前的后突畸形Cobb角平均为25.5°（11°～32°）,术后纠正至平均4.4°（1°～7°）.结论后路椎管减压椎弓根系统治疗胸腰椎骨折并脊髓损伤效果良好.     

Inhibitors of angiotensin-converting enzyme prevent myointimal proliferation after vascular injury

The role of a local angiotensin system in the vascular response to arterial injury was investigated by administering the angiotensin-converting enzyme (CE) inhibitor cilazapril to normotensive rats in which the left carotid artery was subjected to endothelial denudation and injury by balloon catheterization. In control animals, by 14 days after balloon injury, the processes of smooth muscle cell (SMC) proliferation, migration of SMCs from the media to the intima, and synthesis of extracellular matrix produced marked thickening of the intima, with reduction of the cross-sectional area of the lumen. However, in animals that received continuous treatment with the CE inhibitor, neointima formation was decreased (by about 80 percent), and lumen integrity was preserved. Thus, the angiotensin-converting enzyme may participate in modulating the proliferative response of the vascular wall after arterial injury, and inhibition of this enzyme may have therapeutic applications to prevent the proliferative lesions that occur after coronary angioplasty and vascular surgery.     

Macrophage spreading: inhibition in delayed hypersensitivity

The capacity of peritoneal macrophages to spread was studied with cells of mice infected with Listeria monocytogenes and with cells of guinea pigs sensitized with BCG (bacille Calmette Guérin) vaccine or immunized with ovalbumin. In macrophages taken from animals having delayed hypersensitivity, this ability was markedly decreased by the presence of specific antigen for less than 1 hour. Such an effect was not observed in guinea pigs having only circulating antibodies.     

自动站仪器维护及异常记录处理

针对中国气象局改革要求地面观测系统设备运行保障质量、地面观测资料传输正常、地面观测数据正确,在日常工作中观测人员应对自动站仪器经常维护,对常见故障能及时处理.每日日出后和日落前应巡视观测场和值班室内的自动气象站设备,白天每正点前30 min要查看前2h和本小时数据采集是否正常;一般1～2d重启计算机,每天19：00应检查自动站采集器时钟对时;己实现自动观测的要素数据异常,正点时次的记录按照先分钟数据替代、备份自动站记录、内插记录的顺序代替,以保证数据的准确性.     

胡杨的夜间蒸腾——来自树干液流、叶片气体交换及显微结构的证据

不完全的气孔关闭引起的夜间蒸腾在不同物种和环境中普遍存在,且其大小与水汽压差和土壤水分有效性正相关,这意味着荒漠河岸林是研究夜间蒸腾的理想区域。本文基于木质部液流、叶片气体交换、显微结构及环境因子测定证实了胡杨夜间蒸腾的存在:1)夜间叶片气孔是不完全关闭的,平均气孔导度为45 mmol/(m2·s),远大于文献报道的杨属最小气孔导度(约为5 mmol/(m2·s)),平均蒸腾速率为0.7 mmol/(m2·s),两者分别占白天的26%和17%,这表明高的气孔导度和蒸腾速率主要是气孔开放引起;2)木质部平均液流速率白天为31.3 cm/h,夜间为16.5 cm/h,约为白天的53%,无论是白天还是夜间,液流速率与水汽压差均呈显著的对数关系,水汽压差可以解释55%的夜间液流变化,这表明夜间液流由蒸腾和组织补水两部分组成,因此,如何将夜间液流区分为夜间蒸腾和组织补水还有待进一步研究。午夜后液流速率的增加与木质部水势和径向生长变化是一致的,而与水汽压差是相反的,说明午夜后液流速率的增加是组织补水而非蒸腾。      

Transmissible Agent Associated with 26 Types of Experimental Mouse Neoplasms

A transmissible agent or factor has been found to be associated with all transplanted and spontaneous experimental tumors examined. This observation was made possible by utilization of a biochemical response of normal animals when inoculated with plasma or organ extracts from tumor-bearing hosts. This transmissible enzymic "lesion" is expressed by a five- to tenfold increase in the plasma lactic dehydrogenase activity of the injected normal test animals. The factor is heat labile, passes through bacteria-retaining filters, but is nondialyzable. It is partially sedimented by centrifugation at 100,000g for 1 hour.