A new group-training procedure for habituation demonstrates that presynaptic glutamate release contributes to long-term memory in Caenorhabditis elegans

In the experiments reported here we have developed a new group-training protocol for assessing long-term memory for habituation in Caenorhabditis elegans. We have replicated all of the major findings of the original single-worm protocol using the new protocol: (1) distributed training produced long-term retention of training, massed training did not; (2) distributed training at long interstimulus intervals (ISIs) produced long-term retention, short ISIs did not; and (3) long-term memory for distributed training is protein synthesis-dependent as it could be blocked by heat shock during the inter-block interval. In addition, we have shown that long-term memory for habituation is graded, depending on the number of blocks of stimuli in training. The inter-block interval must be >40 min for long-term retention of training to occur. Finally, we have tested long-term memory for habituation training in a strain of worms with a mutation in a vesicular glutamate transporter in the sensory neurons that transduce tap (eat-4). The results from these eat-4 worms indicate that glutamate release from the sensory neurons has an important role in the formation of long-term memory for habituation.     

Updating egocentric representations in human navigation

Seven experiments tested whether human navigation depends on enduring representations, or on momentary egocentric representations that are updated as one moves. Human subjects pointed to unseen targets, either while remaining oriented or after they had been disoriented by self-rotation. Disorientation reduced not only the absolute accuracy of pointing to all objects ('heading error') but also the relative accuracy of pointing to different objects ('configuration error'). A single light providing a directional cue reduced both heading and configuration errors if it was present throughout the experiment. If the light was present during learning and test but absent during the disorientation procedure, however, subjects showed low heading errors (indicating that they reoriented by the light) but high configuration errors (indicating that they failed to retrieve an accurate cognitive map of their surroundings). These findings provide evidence that object locations are represented egocentrically. Nevertheless, disorientation had little effect on the coherence of pointing to different room corners, suggesting both (a) that the disorientation effect on representations of object locations is not due to the experimental paradigm and (b) that room geometry is captured by an enduring representation. These findings cast doubt on the view that accurate navigation depends primarily on an enduring, observer-free cognitive map, for humans construct such a representation of extended surfaces but not of objects. Like insects, humans represent the egocentric distances and directions of objects and continuously update these representations as they move. The principal evolutionary advance in animal navigation may concern the number of unseen targets whose egocentric directions and distances can be represented and updated simultaneously, rather than a qualitative shift in navigation toward reliance on an allocentric map.     

Perception of dynamic acoustic patterns by an individual with unilateral verbal auditory agnosia

Previous studies have found that subjects diagnosed with verbal auditory agnosia (VAA) from bilateral brain lesions may experience difficulties at the prephonemic level of acoustic processing. In this case study, we administered a series of speech and nonspeech discrimination tests to an individual with unilateral VAA as a result of left-temporal-lobe damage. The results indicated that the subject's ability to perceive steady-state acoustic stimuli was relatively intact but his ability to perceive dynamic stimuli was drastically reduced. We conclude that this particular aspect of acoustic processing may be a major contributing factor that disables speech perception in subjects with unilateral VAA.     

In the eye of the storm: race and genomics in research and practice

The difficulties of operationalizing race in research and practice for social, behavioral, and genetic researchers and practitioners are neither new nor related to recent genetic knowledge. For geneticists, the bases for understanding groups are clines, observed traits that gradually change in frequency between geographic regions without distinct identifiable population boundaries and population histories that carry information about the distribution of genetic variants. For psychologists, race may not exist or be a social and cultural construct associated with fluid social inferences. Because definitions of populations and race can be socially and biologically incongruent, the authors suggest that geneticists and social and behavioral scientists and clinicians attend to external validity issues by operationalizing population and racial categories and avoiding race proxies for other biological, social, and cultural constructs in research designs, data analyses, and clinical practice.     

Mothers' affect in the homework context: the importance of staying positive

This research investigated mothers' affect in the context of children's homework. Mothers (N = 109) of children 8 to 12 years old were interviewed daily about their affect while interacting with children, their assistance with children's homework, and children's behavior while completing homework. At this time and 6 months later, children's motivational and emotional functioning was assessed. Although mothers' negative affect was lower than their positive affect, it was elevated on days their assistance with homework was high. This was accounted for by mothers' perceptions of children as helpless on days they provided heightened assistance. Mothers' positive affect in the homework context buffered children's motivational and emotional functioning against mothers' negative affect as well as children's helplessness.     

Is the curve relating temperature to aggression linear or curvilinear? A response to Bell (2005) and to Cohn and Rotton (2005)

P. Bell recommended examining the relationship between temperature and assaults during the hottest times of day and during the hottest months of the year. The authors' analyses of these data show a linear rather than inverted U-shaped relationship between temperature and assault during the hottest times of day and in the hottest months of the year. E. Cohn and J. Rotton recommended analyzing the 6 hr with the highest assaults versus the 6 hr with the lowest assaults. During high assault periods, there is a strong positive linear relationship between temperature and assault. During low assault periods, there is no relationship between temperature and assaults. Assaults and other violent crimes might decrease when temperatures are very hot, but the Minneapolis data set does not allow for testing of this hypothesis because Minneapolis is too cold.     

"结构":解读古典经济学哲学构架的逻辑中轴--瓦尔特·本雅明:作品、生活、时代和历史的交叠

马克思的"古典经济学"概念具有明确内涵、外延并与一定的"知识型"相关,这与西方学者在一般的、含糊的意义使用这个概念具有根本的异质性.它界划了一种分析的范式,说明了马克思与资产阶级经济学之间存在着"知识型"的断裂,这种分析范式就是从配第和布阿吉尔贝尔开始的探讨社会结构及由这种结构所决定的运动规律,这是"古典经济学"概念之独特内涵所在.福柯等人忽视了古典经济学的"结构"视角而从"劳动"范畴出发,认为马克思对李嘉图的修正在西方知识的最深层中并未产生真正的间断性,这是没有读懂马克思"古典政治经济学"的真正内涵.     

百般谏诤皆为民--晏婴在《晏子春秋》中的谏诤形象

晏婴以极忠尽谏闻名,而其劝谏的主要内容便是要齐君效法古之贤君爱民、重民,体现出中国传统文化中的民本思想.本文以《晏子春秋》为据,描述晏婴的谏诤形象和高超的进谏艺术与技巧.