Aspects of Code-Specific Memory Development

We investigated the development of code specific representations of different kinds of information in long term memory. Forty second graders, 40 sixth graders and 40 adults learned the associations between 12 pictures and one position each in a 4 × 3 grid of squares, 12 pictures and 1 of 12 monosyllabic words each or 12 pictures and 1 of 12 faces. After a 3 min distractor task, a picture was presented in the retrieval phase, and the associated position, word or face had to be selected. Performance in the verbal condition improved as a function of age, while performance in the spatial condition turned out to be independent of age, and the performance in the facial condition showed a difference between both child groups and the adults. The results revealed a developmental difference of code specific representation of different kinds of information.     

The role of autonomic arousal in feelings of familiarity

Subjective feelings of familiarity associated with a stimulus tend to be strongest when specific information about the previous encounter with the stimulus is difficult to retrieve (e.g., the butcher-on-the-bus phenomenon; [Mandler, G. (1980). Recognizing: The judgment of previous occurrence. Psychological Review, 87, 252-271.]). When a stimulus has been encountered previously and the circumstances of the encounter cannot be recollected, additional cognitive resources may be directed toward recollection processes; this resource allocation is accompanied by autonomic arousal [Dawson, M. E., Filion, D. L., & Schell, A. M. (1989). Is elicitation of the autonomic orienting response associated with allocation of processing resources?. Psychophysiology, 26, 560-572]. One easily measurable index of autonomic arousal is the skin conductance response (SCR). In the present study, participants studied lists of words and then gave recognition ratings to briefly displayed and masked studied and nonstudied test words while their SCRs were monitored. Results revealed a relationship between recognition ratings and the temporal characteristics of the SCR, supporting the idea that feelings of familiarity are indeed "feelings" in that they stem from autonomic arousal associated with cognitive resource allocation.     

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.     

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.     

Neophilia in domestic dogs (Canis familiaris) and its implication for studies of dog cognition

This study examined novel-object preference in dogs. In a free choice test 17 dogs were presented with a novel toy in a line up with two familiar toys. The unfamiliar object was chosen first in 38 out 50 tests suggesting a strong preference for novel over familiar items. Neophilia may be an adaptive trait for domestic dogs that has helped their adaptation towards man.     

客体工作记忆任务中大脑皮层活动的记忆负荷效应

利用128导事件相关电位技术,采用延迟匹配任务的实验范式,测查了20名正常被试完成不同负荷客体任务时的皮层慢电位（slow cortical potentials,简称sp成分）,实验发现：背侧前额叶在刺激呈现后的700ms到1400ms出现记忆负荷效应,高负荷任务诱发的sp成分显著负于低负荷任务;低负荷任务诱发的sp成分在左前额区（500~1800ms）、左前额-中央区（700~1800ms）、左中央-顶叶区（1000~1400s和1800~4800ms）、右前额区（1800~4800ms）和右前额-中央区（1400~4800ms）显著负于高负荷任务,出现记忆负荷效应,但这种负荷效应在左右大脑半球所反映的心理意义可能不同