Noise avoidance in the C57BL/6J mouse

Noise was evaluated as an aversive stimulus in the C57BL/6J mouse, using a simple escape/avoidance procedure in which mice could terminate noise by entering and remaining in a designatedsafe area (corner or side) of a square apparatus. Exposed to pulsed noise of 87.5–90 dB, mice spent 45%–50% of total corner time in the safe corner or approximately 80% of total time in the safe side. Acquisition was significantly faster with moderate intensities of pulsed noise (87.5–90 dB) than it was with high-intensity pulsed noise (100 dB). In comparisons of continuous as opposed to pulsed noise, acquisition was significantly faster with continuous (87.5-dB) noise than it was with pulsed noise, and continuous noise was shown in a choice procedure to be more aversive. Continuous noise caused significant, though not severe, suppression of activity, but pulsed noise caused virtually none. Thus, pulsed noise is a mildly aversive stimuhis for C57BL/6J mice and may have promise for the study of stress-induced behaviors in freely moving animals, but continuous noise is clearly more effective for rapid short-term conditioning.     

Magnetic compass orientation in C57BL/6J mice

We report evidence for a robust magnetic compass response in C57BL/6J mice. Mice were trained to build their nests in one of four magnetic directions by creating a light gradient along the long axis of a rectangular cage and positioning a nest box at the opposite (dark) end. The mice were then tested overnight in a circular, visually symmetrical arena in one of four magnetic field alignments. The positions of the nests built in the test arena showed strong unimodal orientation in the magnetic direction coinciding with the dark end of the training cage.     

Effect of circadian phase on context and cued fear conditioning in C57BL/6J mice

We examined context-dependent and tone-cued fear conditioning during the activity and rest periods of C57BL/6J mice. Wheel-running activity was measured continuously as a marker of circadian phase. To control the effects of light on the response, the animals were kept in a skeleton photoperiod (two 15-min light pulses per day, indicating the beginning and the end of the day). Half the animals were trained and tested for context-dependent fear conditioning 2 h after the morning light pulse; the other half were trained and tested 2 h after the evening light pulse. Animals were tested every 24 h for 5 days to analyze the conditioned response and the rate of extinction. They were then trained for tonecued fear conditioning at the same time and tested for 5 consecutive days. A significant difference between the morning and the evening groups was observed in the conditioning level and extinction rate of context-dependent fear conditioning, but not in tone-cued fear conditioning. These results suggest a modulating effect of the biological clock on the context fear-conditioning pathway.     

C57/BL-6J小鼠感光细胞发育实验观察

目的观察C57小鼠视感光细胞的发育及微细结构,为应用C57小鼠提供实验依据,对了解人类视网膜感光细胞的发育提供参考和帮助。方法将出生后第3、7、14、21、28d的C57小鼠及成鼠采用4%多聚甲醛灌注固定后,取眼球,冰冻切片,应用opsin单克隆抗体免疫组织化学法检测感光细胞的发育。结果免疫组织化学法显示：C57小鼠出生第3d,视网膜尚未完全分层,染色阴性,未见成熟感光细胞;出生第7d,有少量细胞染色阳性,可见少量的感光细胞;出生第14、21、28d及成鼠染色阳性的感光细胞逐渐增多,视网膜分层达到10层。结论 C57小鼠视网膜感光细胞在出生后开始发育,至第7d可见阳性细胞,第14d视网膜层数及感光细胞基本和成年鼠一致,而后逐渐达到成熟。     

C_(57)BL小鼠生殖效率的研究

对C57BL小鼠生殖系统进行了解剖学和细胞学研究 ,结果表明 :性周期发情期的鉴定是提高小鼠受孕率的关键 温度、光照、噪音、湿度及营养等因素对小鼠生殖效率影响较大     

Emotionality related to maternal cannibalism in BALB and C57BL mice

Twenty-four female mice from two inbred strains, BALB and C57BL, were tested for emotional behavior. Half of the animals had successfully raised their first litter to weaning, while the other half had eaten their first litter. Cannibalistic females of both strains were found to be more prone to auditory stress than controls. However, the relationship between emotional defecation and cannibalism was found to interact with strain, suggesting an optimum level of arousal.     

Acquisition and extinction of conditioned nicotine analgesic tolerance

These studies demonstrated the acquisition and extinction of conditioned tolerance to the analgesic effect of nicotine in rats. In Experiment 1, distinctive environmental cues were either paired or unpaired with nicotine. Following acquisition, the paired group was more tolerant to nicotine than the unpaired and saline groups. Conditioned tolerance was extinguished in the paired group after placebo sessions in the distinctive environment. Experiment 2 examined whether the distinctive environment functioned as a CS or as an occasion setter for injection cues. After acquisition, exposure to the distinctive environment, with or without placebo injections, resulted in extinction. This demonstrates that the distinctive environment served as a CS, not as an occasion setter for injection cues.     

Acquisition and extinction in the presence of the same intertrial stimuli: The effects of partial reward

Two groups of rats (N = 11) were trained at two trials a day for 16 days in Phase I and 13 days in Phase II. Responses on Trial 1 were always rewarded in both phases. Percentage of reward (50% vs 100%) was varied on Trial 2 of each day of Phase I. Trial 2 on each day of Phase II was never rewarded. A partial reward effect (PRE) was observed on Trial 2 of Phase II. The implications of the results for intertrial explanations of the PRE were discussed.     

Acquisition and extinction of runway performance under escape,avoidance, and partial-avoidance procedures

The acquisition and extinction of locomotor responses of rats in a straight alley were examined for groups trained under escape, partial-avoidance, and avoidance procedures. During acquisition, one group (escape) received a 0-sec delay between being dropped into the alley and the onset of shock; two groups (partial avoidance) had 0.5- and 1-sec delays; and two groups (avoidance) had delays of 2 and 4 sec. On the final day of acquisition, the partial-avoidance rats displayed higher running speeds than either the escape- or avoidance-trained animals. The 4-sec avoidance group was consistently slower than all other groups. Speeds for all groups decreased during extinction, with rate of decline showing some relation to terminal acquisition level. Relative group performance levels proved to be consistent with a simple arithmetic model based on the assumption that changes in running speeds affect the aversiveness of the situation by altering US duration, CS duration, and effective US length.     

Acquisition,extinction, and reacquisition of a conditional discrimination to avoid shock by goldfish

Goldfish, trained in the shuttlebox to avoid shock, were tested for the acquisition and extinction of a color-matching or a color-oddity conditional discrimination choice response, and then tested for reacquisition. Extinction affected the accuracy of the choice response but not the number of trials with response (response strength). Half of all groups were extinguished with changed signal colors, and half had the same signal colors experienced in acquisition. All groups had the same signal colors in reacquisition that they had experienced in acquisition. Changed-signal oddity groups decremented slightly faster than same-signal oddity groups, providing some support for a generalization decrement interpretation, but same- and changed-signal matching groups did not differ. All groups extinguished on the choice response by the end of extinction. All matching groups, and all oddity groups, regardless of their respective signal colors in extinction, reacquired at the same rate, and faster than in acquisition. These results imply conceptual generalization of extinction effects. Matching-trained groups were found to be slightly superior to oddity-trained groups in both acquisition and reacquisition. Comparisons of these results to positive reinforcement conditional discrimination extinction work, including some procedural suggestions, are made.     

One-trial backward excitatory fear conditioning in rats: Acquisition,retention, extinction,and spontaneous recovery

Water-deprived male albino rats received a single presentation of a 4-sec electric-grid-shock unconditioned stimulus followed by a 4-sec white-noise conditioned stimulus (a single backward conditioning trial.) Excitation conditioned to the noise was indexed in terms of the noise’s subsequent ability to suppress ongoing licking of a water tube. The main findings were: (1) Excitation was acquired and was retained over a 30-day retention interval; (2) although excitation was retained, it did not grow significantly stronger during the interval (there was no incubation effect); (3) excitation was extinguished by noise-alone trials; and (4) excitation showed more spontaneous recovery when extinction trials were separated by 29 days than when separated by only 1 day. Because these results are similar to those in the forward conditioning literature, they seem consistent with, but do not demand, the view that forward and backward excitatory conditioning involve similar learning processes. A current theory that embraces this view is opponent-process theory (Solomon & Corbit, 1974). We suggest that opponent-process theory can (1) account for existing backward conditioning data, (2) explain the phenomenon of incubation that has previously been described in the literature while simultaneously explaining its absence in the present study, and (3) integrate certain nonmonotonic acquisition phenomena that have appeared in both the forward and backward conditioning literatures.     

Imitation and social facilitation in the pigeon

The sight of another pigeon pecking a response key for grain resulted in similar pecking by more pigeons than did the sight of another pigeon eating or the sight of another pigeon (neither pecking nor eating). But more pigeons pecked the response key when they could see another pigeon that was neither pecking nor eating than when no other pigeon was there (whether or not key-light/grain pairings were observable in the adjacent compartment). Finally, observation of another pigeon pecking but not eating produced pecking comparable to observation of both pecking and eating. The presence of both imitation and social facilitation of keypecking were demonstrated. Observation of the consummatory response contributed little to keypecking.     

Transfer of facilitation in the rat

In two experiments, rats solved two concurrent discrimination problems in which one stimulus (i.e., a facilitator) signaled the reinforcement of another stimulus (i.e., a target). Then a transfer test assessed the capacity of facilitators trained in one problem to promote responding to targets trained in the other. Experiment 1 found that a facilitator promoted as much responding to such a transfer target as to the target with which it was originally trained. Transfer was not obtained with a pseudofacilitator that was uninformative, in training, about the reinforcement of its target. Experiment 2 manipulated the stimulus modality of the targets and facilitators. Its results indicated that transfer performance was not due to generalization between training and transfer targets or facilitators. These results parallel those from comparable autoshaping paradigms with pigeons, and they agree with the view that facilitators promote responding by lowering the threshold for activation of the US representation.     

基于μC/OS-Ⅱ的嵌入式数据采集仪的设计与研究

对嵌入式数据采集仪的整体结构进行了概述,详细介绍了系统设计过程中的关键技术:硬件调理电路、网络模块及软件模块的设计,并在设计过程中确立了模块化和层次化的思想。     

对于二语习得中场独立/依存研究的反思

在二语习得中,场独立/依存这两种学习风格受到了人们的关注,但大量研究结果却不一致,有的甚至互相矛盾。本文分析了产生这种结果的原因并引入了柯勃(Kolb)的学习风格理论来阐述学习风格多样性的重要意义。     

IPv6与IPv4网络互通技术及在H3C路由器上NAT-PT网关的实现

IPv6将取代IPv4成为下一代互联网的核心.但在今后较长一段时间内,IPv6、IPv4网络将长期共存.在过渡时期的不同阶段,选择合理的过渡机制是保证IPv4、IPv6网络互通性的有效手段.首先分析和介绍了双栈协议、隧道技术和翻译器技术及各种过渡技术的优点和局限性,介绍了转换网关系统.在过渡初期,转换网关NAT-PT系统作为过渡机制的一种,是解决小规模IPv6网络访问IPv4外网的一种较好的实现方案.最后,给出了H3C-MSR路由器下NAT-PT的实现.     

ADC14C080在高速数据采集电路中的应用

介绍了采样速率达到80MPSP,精度为14bit的模数转换芯片ADC14C080的性能指标。设计了其ADC前端电路。在FPGA中讨论了其控制和存储逻辑。     

Acquisition and extinction of differential responses to signals paired with shock or shock omission in goldfish: Evidence for truly discriminated avoidance learning

Goldfish trained to discriminate between signals paired with shock (S?) and signals paired with shock omission (S+) with a linear presentation procedure, originally learned (OL) to control the signal state of a shuttle box and showed a decided preference for the S+ signal. In Experiment 1, following OL, groups had one OL signal replaced (S+ or S?), both signals replaced (S+ and S?), or the OL signals reversed (S+ and S? reversed) and were then tested in a transfer training procedure. In transfer, groups with one signal replaced maintained discriminated performance at OL levels; the S+ replaced group was slightly superior to the S? replaced group on the first day of transfer. With both OL signals replaced, discrimination dropped to chance performance levels, whereas, with OL signal shock pairing reversed, discrimination performance dropped below chance levels. In Experiment 2, following OL, extinction procedures consisted of turning off the shocker (0% shock) or of shocking 100% or a random 25% of the trials. A fourth extinction procedure (R,) retained the trial start response-dependent shock-omission contingency, but shock differentiating the S+ and S? signals was eliminated entirely. Extinction of the S+/S? discrimination was measured both during extinction training per se and with reversal retraining of the S+/S? discrimination later. Groups for which the OL S+ was paired with shock during extinction extinguished on both measures, but groups for which the OL S? was paired with shock omission did not extinguish, especially as shown by the reversal test procedure. Theoretical implications and the implications for several conditioning procedures are discussed.     

Interference and facilitation produced by noncontingent reinforcement in the appetitive situation

The results of experiments on learned helplessness in the appetitive situation have varied from facilitation to debilitating effects produced by exposure to uncontrollable food. The conditions under which the interference effect (debilitation) may occur were examined in the first three experiments, employing the triadic design. Sixteen sets of conditions were examined. The results suggested that the effect occurs when (1) subjects are preexposed to the manipulandum to be used in the test stage, by having it present during pretreatment with uncontrollable food, and (2) the manipulandum employed during pretreatment is absent during the test stage. Furthermore, under the reverse conditions (test manipulandum absent during pretreatment, and pretreatment manipulandum present during testing) and partial reinforcement of the response contingent subjects during pretreatment, the test performance of rats exposed to uncontrollability was facilitated. Experiment 4 confirmed the occurrence of the interference effect under the suggested conditions. Apparently inconsistent results of previous studies may be interpreted in the light of these findings.