An object-based cost of visual filtering

Although evidence for object-based attention has been reported in a variety of paradigms, few studies have examined directly the relationship between efficiency in the processing of targets and the number of intervening distractors. In five experiments, observers judged whether the vertices of two relevant shapes were of the same height. Experiments 1 and 2 manipulated observers' perceptual set so that identical stimulus displays were perceived as containing either intervening or flanking distractors. The observers were faster when the distractors were flanking rather than intervening between the targets. Experiments 3-5 varied the number of intervening distractors directly. The observers' response latencies correlated positively with the distractor set-size. Because the distractors were highly discriminable from the targets and the spatial separation between the targets and their interactions with the adjacent distractors were held constant, it was unlikely that the differential reaction times across the conditions were caused by lateral inhibition or response competitions from the distractors. The results suggest the existence of an object-based filtering cost. The implications of the present data for attentional selection over noncontiguous regions are also discussed.     

Serial learning by rhesus monkeys: II. Learning four-item lists by trial and error

Three rhesus macaque monkeys were trained to produce novel 4-item lists (A-->B-->C-->D) on which all items were displayed from the start of training. Subjects were previously trained to produce 4-item lists by adding one item at a time (A, A-->B, A-->B-->C, and A-->B-->C-->D; lists K. B. Swartz et al., 1991). Those lists could be mastered by responding to each new item last. To learn lists on which all items were displayed from the start of training, subjects had to recall the consequences of errors and correct responses to each item. Errors ended the trial; correct responses to A, B, or C allowed the trial to continue. A correct response to D produced food reward. Although the probability of executing a 4-item list correctly by chance was .04, each subject mastered 4 novel 4-item lists by trial and error. The ability of monkeys to use a trial-and-error strategy to learn novel lists provides a basis for studying the development of serial expertise in animals.     

锌对细胞凋亡调控研究的一些思考

锌是机体必需的微量元素,它能够抑制细胞凋亡,也可以诱导细胞凋亡。阐述近年有关锌对细胞凋亡的研究结果,提出要全面,辩证地看待二者之间的关系。     

Imaging high-resolution structure of GFP-expressing neurons in neocortex in vivo

To detect subtle changes in neuronal morphology in response to changes in experience, one must image neurons at high resolution in vivo over time scales of minutes to days. We accomplished this by infecting postmitotic neurons in rat and mouse barrel cortex with a Sindbis virus carrying the gene for enhanced green fluorescent protein. Visualized with 2-photon excitation laser scanning microscopy, infected neurons showed bright fluorescence that was distributed homogeneously throughout the cell, including axonal and dendritic arbors. Single dendritic spines could routinely be resolved and their morphological dynamics visualized. Viral infection and imaging were achieved throughout postnatal development up to early adulthood (P 8-30), although the viral efficiency of infection decreased with age. This relatively noninvasive method for fluorescent labeling and imaging of neurons allows the study of morphological dynamics of neocortical neurons and their circuits in vivo.     

Rethinking technology, revitalizing ethics: Overcoming barriers to ethical design

This paper explores the role of ethics in design. Traditionally, ethical questions have been seen as marginal issues in the design of technology. Part of the reason for this stems from the widely held notion of technology being “out of control.” This notion is a barrier to what I call “ethical design” because it implies that ethics has no role to play in the development of technology. This view, however, is challenged by recent work in the field of Science and Technology Studies (STS). Looking into the dynamics of technological change, STS scholars argue that human choices are present at every stage of a technology’s development and, furthermore, that human values are reflected in the very design of artifacts. This alternative view suggests that ethics can and should be included in the design process. Drawing on examples from the privacy arena. I point to some of the potential advantages of addressing ethical concerns early on in the design of a technology. I conclude with some general strategies for bringing ethics back into design. A version of this paper was presented at ETHICOMP98, the Fourth International Conference on Ethical Issues of Information Technology, March 25–27, 1998, Erasmus University, the Netherlands. Patrick Feng is a Ph.D. student in the Science and Technology Studies Department at Rensselaer. His research focuses on the development of technical standards that are designed to address social values such as privacy and trust.     

论原始及部派佛教的"六识"说

本文探讨与分析了原始及部派佛教的"六识"说,尤其从心识与五蕴、与十二处、与十八界、与心所、与其他诸法、与四缘的联系上,指出"六识"说存在的局限,而正是由于这些局限,才必然导致更为严密、周详,尤其非心理主义的唯识学的"八识"说的出现.     

"道物无际"--道教生态哲学纲要

道教生态哲学的基础围绕着道教的最高理念"道"及最基本范畴"物"生"神"而展开."道"作为道教信仰的终极理念,具有至高无上的地位,它与其它宗教或思想体系中的最高理念,如上帝、安那、梵(印度教吠檀多派)、绝对精神、自由意志等等范畴一样处于核心的地位,虽然这些范畴在解释一切精神和存在现象的作用上不尽相同.在道教哲学中,"道"是无所不覆、自生自化、永恒存在、派生万物的形而上的宇宙本体,是贯穿于整个自然界、人世间和神仙世界之中的最高理念.除了作为最高理念的"道"外,"物"生"和"神"也是道教生态哲学的最基本范畴."物"是对物质、万物、实物、器物、财物等具体事物的抽象,主要指有形的、变化的、局部的、杂多的现象存在."生"是对生命、身体、人生、生物、生物圈、生态环境的抽象,也包括事物的有机活动和转化的功能,如事物的生成、生长和生化."神"是对精神、神仙、神明的抽象,它是对"物"和"生"的提升、超越.道教将"道"贯穿于"物"生"神"三界,具体演化为自然界(物)、人世间(生)和神仙界(神),或物质世界、生命世界和神仙世界."物"生"神"的相互关系及其与"道"的关系构成了道教生态哲学的基础.     

The level of cholinergic nucleus basalis activation controls the specificity of auditory associative memory

Learning involves not only the establishment of memory per se, but also the specific details of its contents. In classical conditioning, the former concerns whether an association was learned while the latter discloses what was learned. The neural bases of associativity have been studied extensively while neural mechanisms of memory specificity have been neglected. Stimulation of the cholinergic nucleus basalis (NBs) paired with a preceding tone induces CS-specific associative memory. As different levels of acetylcholine may be released naturally during different learning situations, we asked whether the level of activation of the cholinergic neuromodulatory system can control the degree of detail that is encoded and retrieved. Adult male rats were tested pre- and post-training for behavioral responses (interruption of ongoing respiration) to tones of various frequencies (1-15 kHz, 70 dB, 2 s). Training consisted of 200 trials/day of tone (8.0 kHz, 70 dB, 2 s) either paired or unpaired with NBs (CS-NBs = 1.8 s) at moderate (65.7+/-9.0 microA, one day) or weak (46.7+/-12.1 microA, three training days) levels of stimulation, under conditions of controlled behavioral state (pre-trial stable respiration rate). Post-training (24 h) responses to tones revealed that moderate activation induced both associative and CS-specific behavioral memory, whereas weak activation produced associative memory lacking frequency specificity. The degree of memory specificity 24 h after training was positively correlated with the magnitude of CS-elicited increase in gamma activity within the EEG during training, but only in the moderate NBs group. Thus, a low level of acetylcholine released by the nucleus basalis during learning is sufficient to induce associativity whereas a higher level of release enables the storage of greater experiential detail. gamma waves, which are thought to reflect the coordinated activity of cortical cells, appear to index the encoding of CS detail. The findings demonstrate that the amount of detail in memory can be directly controlled by neural intervention.     

Traits and stories: links between dispositional and narrative features of personality

Dispositional traits and life narratives represent two different levels of personality that have not previously been empirically linked. The current study tested five hypotheses connecting Big-Five traits to life-narrative indices of emotional tone, theme, and structure. Students (Study 1) and adults (Study 2) completed a self-report measure of the Big-Five traits and provided extended written accounts of either ten (students) or eight (adults) key life-narrative scenes, including life high points, low points, and turning points. Content analysis of the narrative data revealed that for both samples Neuroticism was positively associated with an emotionally negative life-narrative tone, Agreeableness was correlated with narrative themes of communion (e.g., friendship, caring for others), and Openness was strongly associated with the structural complexity of life narrative accounts. Contrary to prediction, however, Conscientiousness was not consistently associated with themes of agency (e.g., achievement, self-mastery) and Extraversion was unrelated to positive narrative tone. The results are discussed in the context of contemporary research and theorizing on the narrative study of lives and the relation of narrative research in personality to more conventional, trait-based approaches.