Ethanol state-dependent memory: involvement of dorsal hippocampal muscarinic and nicotinic receptors

In the present study, the effects of bilateral injections of cholinergic agents into the hippocampal CA1 regions (intra-CA1) on ethanol state-dependent memory were examined in mice. A single-trial step-down passive avoidance task was used for the assessment of memory retention in adult male NMRI mice. Pre-training intraperitoneal injection (i.p.) of ethanol (0.25, 0.5 and 1 g/kg) dose dependently induced impairment of memory retention. Pre-test administration of ethanol (0.5 and 1 g/kg, i.p.) induced state-dependent retrieval of the memory acquired under pre-training ethanol (1 g/kg, i.p.) influence. Pre-test intra-CA1 injection of physostigmine (2.5 and 5 μg/mouse, intra-CA1) or nicotine (0.3 and 0.5 μg/mouse, intra-CA1) improved pre-training ethanol (1 g/kg)-induced retrieval impairment. Moreover, pre-test administration of physostigmine (2.5 and 5 μg/mouse, intra-CA1) or nicotine (0.3 and 0.5 μg/mouse, intra-CA1) with an ineffective dose of ethanol (0.25 g/kg) significantly restored the retrieval and induced ethanol state-dependent memory. Pre-test intra-CA1 injection of the muscarinic receptor antagonist, atropine (4 and 8 μg/mouse, intra-CA1) or the nicotinic receptor antagonist, mecamylamine (2 and 4 μg/mouse, intra-CA1) 5 min before the administration of ethanol (1 g/kg, i.p.) dose dependently inhibited ethanol state-dependent memory. Pre-test intra-CA1 administration of physostigmine (0.5, 2.5 and 5 μg/mouse), atropine (2, 4 and 8 μg/mouse), nicotine (0.1, 0.3 and 0.5 μg/mouse) or mecamylamine (1, 2 and 4 μg/mouse) alone cannot affect memory retention. These findings implicate the involvement of a dorsal hippocampal cholinergic mechanism in ethanol state-dependent memory and also it can be concluded that there may be a cross-state dependency between ethanol and acetylcholine.     

Environmental cue saliency influences the vividness of a remote spatial memory in rats

The Morris water maze is frequently used to evaluate the acquisition and retrieval of spatial memories. Few experiments, however, have investigated the effects of environmental cue saliency on the strength or persistence of such memories after a short vs. long post-acquisition interval. Using a Morris water maze, we therefore tested in rats the effect of the saliency of distal cues on the vividness of a recent (5 days) vs. remote (25 days) memory. Rats trained in a cue-enriched vs. a cue-impoverished context showed a better overall level of performance during acquisition. Furthermore, the probe trials revealed that the rats trained and tested in the cue-impoverished context (1) spent less time in the target quadrant at the 25-day delay, and (2) swam shorter distances in the target area, with fewer crossings at both 5- and 25-day delays, as compared to their counterparts trained and tested in the cue-enriched context. Thus, the memory trace formed in the cue-enriched context shows better resistance to time, suggesting an implication of cue saliency in the vividness of a spatial memory.     

Message content,group identification and the intergroup sensitivity effect: Responses to the message and recognition memory

An intergroup sensitivity effect (ISE) is people's tendency to react more negatively to a criticism when it was made by an outgroup member than when the same criticism was made by an ingroup member. The present study investigated variation in ISE when the criticism was varied in terms of valence (absence of positive qualities or presence of negative qualities) and level of abstraction (traits or behaviours). Dependent measures were emotional reactions to the criticism, perceived constructiveness, ingroup bias, and recognition memory for the criticism. All participants showed an ISE to the negative abstract criticism. In addition, consistent with the social identity account of ISE, participants' levels of identification with their ingroup moderated the ISE in some of the measures.     

Spontaneous recovery of consummatory behavior, but not of consummatory successive negative contrast

Five experiments were designed to study spontaneous recovery (SR) in two situations involving consummatory behavior: consummatory successive negative contrast (cSNC) and consummatory extinction (cE). SR of consummatory suppression should occur if incentive downshift induces an egocentric memory encoding information about the emotional reaction to the downshift that is counterconditioned or extinguished during exposure to the downshifted reward. SR of cSNC failed to occur after resting periods of 24, 96, or 336 h interpolated following complete (Experiment 1) and incomplete (Experiment 2) recuperation of consummatory behavior, and was not induced by the opioid-receptor antagonist naloxone (2 mg/kg), known to enhance cSNC (Experiment 3). However, SR of consummatory behavior occurred across sessions in cSNC (Experiment 3) and cE (Experiments 4-5). Furthermore, naloxone facilitated cE without affecting SR (Experiments 4-5). These results are discussed in relation to evidence for the development of an egocentric memory of the aversive downshift experience in consummatory situations.     

Conscious and unconscious forms of memory in different implicit tests

This study investigated how shallow processing (complexity rating), deep processing (pleasantness rating), and semantic generation (translating from English) of Chinese words affects conscious memory (CM) and unconscious memory (UM) of the words with three implicit tests: word association, word identification, and word-stem completion. A metacognition-based dissociation procedure was used to estimate the two forms of memory for each test. Except for the shallow condition preceding the word-association test, all three study conditions produced a positive effect on the estimate of CM. The estimate of UM did not benefit from any of the study conditions in the word-association test, it benefited from the shallow and deep conditions but did not benefit from the generation condition in the stem-completion test, and it benefited from the shallow condition but did not benefit from the deep and generation conditions in the word-identification test. Implications of these results for CM and UM operations are discussed.     

Behavioral cues that great apes use to forage for hidden food

We conducted three studies to examine whether the four great ape species (chimpanzees, bonobos, gorillas, and orangutans) are able to use behavioral experimenter-given cues in an object-choice task. In the subsequent experimental conditions subjects were presented with two eggs, one of which contained food and the other did not. In Study 1 the experimenter examined both eggs by smelling or shaking them, but only made a failed attempt to open (via biting) the egg containing food. In a control condition, the experimenter examined and attempted to open both eggs, but in reverse order to control for stimulus enhancement. The apes significantly preferred the egg that was first examined and then bitten, but had no preference in a baseline condition in which there were no cues. In Study 2, we investigated whether the apes could extend this ability to cues not observed in apes so far (i.e., attempting to pull apart the egg), as well as whether they made this discrimination based on the function of the action the experimenter performed. Subjects significantly preferred eggs presented with this novel cue, but did not prefer eggs presented with a novel but functionally irrelevant action. In Study 3, apes did not interpret human actions as cues to food-location when they already knew that the eggs were empty. Thus, great apes were able to use a variety of experimenter-given cues associated with foraging actions to locate hidden food and thereby were partially sensitive to the general purpose underlying these actions.     

Enhanced recognition of emotional stimuli in the chimpanzee (<Emphasis Type="Italic">Pan troglodytes</Emphasis>)

Humans often have a better memory of emotional events than neutral events. From the comparative-cognitive perspective, we explored the enhancement of recognition memory by emotion in chimpanzees (Pan troglodytes) using a serial probe recognition task. In this task, we sequentially presented a list of pictures to subjects and then tested their recognition of specific pictures from within the list. We selected pictures of aggressive chimpanzees as emotional stimuli and less tensed, relaxed chimpanzees as neutral stimuli. In Experiment 1, we gave four-item lists to two young chimpanzees; one showed significantly greater recognition of pictures depicting aggressive chimpanzees than neutral ones. In Experiment 2, this chimpanzee was further tested using a recognition task with eight-item lists. The subject again showed better recognition of emotional stimuli than neutral. Furthermore, the presence of an emotional stimulus in the list also facilitated recognition of the neutral item immediately following it. Overall, although only one of the two chimpanzees showed enhanced recognition memory by emotional stimuli, this is the first demonstration of such a response in the chimpanzee. The findings are discussed in comparison with those of human studies.     

繁衍线索对风险信息加工的影响

进化理论认为风险行为与求偶有关。研究通过比较求偶信息(异性照片或描述异性的词语)、养育后代(孕妇照片)及奖赏信息(金牌照片等)试图进一步探讨繁衍线索对两性知觉和判断风险信息的影响。研究1中, 被试描述理想约会对象后求偶动机得到激发, 相对于描述晴朗天气的控制组, 求偶动机让两性更慢地从高风险信息(如滑雪、冲浪等)转移注意力, 且两性对风险信息的注意转移与社群性向无关。研究2显示, 相对于养育后代和奖赏信息, 求偶信息更为迅速地促使男性对高风险信息做出判断, 但求偶信息让女性比男性更慢地对高风险信息做出判断。研究结果进一步证实了自然选择理论及性选择理论对两性加工风险信息的认知机制具有预测作用。     

限制性饮食者对食物线索的认知偏向：行为和脑机制的证据

限制饮食是为了控制体重, 长期严格地控制进食的倾向。大量研究表明相对于非限制性饮食者, 限制性饮食者对食物线索尤其是高能量或高美味食物线索存在认知偏向。这种偏向是基于一定的脑神经基础的如前额叶背内侧, 小脑等区域。未来研究应设置严格的筛选标准, 运用视觉odd-one-out和学习-再认实验范式, 重视认知神经机制的探讨, 开展中国限制性饮食者对食物线索加工的认知机制和主要影响因素模型的系统研究。     

Bonus of rebate?: the impact of income framing on spending and saving

All income increases a person's absolute wealth, but consumption decisions may be based more heavily on perceived changes in wealth. Change is computed by comparing a current state with a former state, and we predicted that people would be more likely to spend income framed as a gain from a current wealth state than income framed as a return to a prior state. Four experiments confirmed this prediction on people's memory for spending of a government tax rebate (Experiment 1), on unobtrusive self‐report measures of spending an unexpected windfall (Experiments 2 and 3), and on actual spending on items for sale in a laboratory experiment (Experiment 4). These results can be explained, at least in part, by the reference points implied in the framing of income (follow‐ups to Experiments 1 and 4). Discussion focuses on implications for the consumption of other commodities, assessments of risk, and government tax policies. Copyright © 2006 John Wiley & Sons, Ltd.