Low environmental calcium blocks long-term memory formation in a freshwater pulmonate snail

The freshwater snail Lymnaea stagnalis (L.) is considered a calciphile and exhibits reduced growth and survival in environments containing less than 20 mg/l environmental calcium. Although it has no apparent effect on survival at 20 mg/l, reducing environmental calcium increases metabolic demand, and as such we consider that this level of calcium acts as a stressor on the snail. We exposed snails to acute periods of low environmental calcium and tested their ability to form intermediate-term memory (ITM) and long-term memory (LTM) following one trial operant conditioning (1TT) to reduce aerial respiratory activity in hypoxic conditions. We also assessed whether there were changes in the electrophysiological properties of a single neuron, right pedal dorsal 1 (RPeD1), which has been demonstrated to be necessary for LTM formation. Following training in high (80 mg/l) environmental calcium, L. stagnalis formed ITM and LTM lasting 24 h and demonstrated a significant reduction in all activity measured from RPeD1; however when snails were exposed to low (20 mg/l) environmental calcium they were able to form ITM but not LTM. Although no behavioral LTM was formed, a partial reduction in RPeD1 activtiy measured 24 h after training was observed, indicating a residual effect of training. The strong effect that environmental calcium concentration had on physiology and behavior in response to training to reduce aerial respiration in L. stagnalis suggests that it is an element of gastropod husbandry that needs to be carefully considered when studying other traits. This study also indicates that L. stagnalis found naturally in low calcium environments may be less able to adapt to novel stressors than populations found in harder waters.     

Interference with reelin signaling in the lateral entorhinal cortex impairs spatial memory

Entorhinal neurons receive extensive intracortical projections, and form the primary input to the hippocampus via the perforant pathway. The glutamatergic cells of origin for the perforant pathway are distinguished by their expression of reelin, a glycoprotein involved in learning and synaptic plasticity. The functional significance of reelin signaling within the entorhinal cortex, however, remains unexplored. To determine whether interrupting entorhinal reelin signaling might have consequences for learning and memory, we administered recombinant receptor-associated protein (RAP) into the lateral entorhinal cortex (LEC) of young Long-Evans rats. RAP prevents reelin from binding to its receptors, and we verified the knockdown of reelin signaling by quantifying the phosphorylation state of reelin’s intracellular signaling target, disabled-1 (DAB1). Effective knockdown of reelin signaling was associated with impaired performance in the hippocampus-dependent version of the water maze. Moreover, inhibition of reelin signaling induced a localized loss of synaptic marker expression in the LEC. These observations support a role for entorhinal reelin signaling in spatial learning, and suggest that an intact reelin signaling pathway is essential for synaptic integrity in the adult entorhinal cortex.     

学业优秀者和学业不良者的倒摄抑制比较 ——从结构化和非结构化角度

以汉字为实验材料,以学业优秀者和学业不良者为被试,探讨学习材料的结构化和非结构化性质对倒摄抑制产生的影响,以及两类学生学习两类材料时的倒摄抑制差异。并通过指导语,逐步揭示结构化材料中的规则,迫使被试采用有效的学习策略,来观察倒摄抑制的变化情况。结果表明:一、与非结构化材料相比,学习结构化材料表现出更好的记忆绩效,但未发现两者对倒摄抑制的不同影响;二、和学优者相比,学业不良者的记忆绩效较差,倒摄抑制值也较大;三、对材料规则的提示会促进学业不良学生的记忆绩效,降低倒摄抑制,但对学习优秀者的影响不大;四、一些汉字识别特征影响倒摄抑制,如当干扰项和目标项构形相同时,会降低倒摄抑制。     

Learning language from the input: why innate constraints can't explain noun compounding

Do the production and interpretation of patterns of plural forms in noun-noun compounds reveal the workings of innate constraints that govern morphological processing? The results of previous studies on compounding have been taken to support a number of important theoretical claims: first, that there are fundamental differences in the way that children and adults learn and process regular and irregular plurals, second, that these differences reflect formal constraints that govern the way the way regular and irregular plurals are processed in language, and third, that these constraints are unlikely to be the product of learning. In a series of seven experiments, we critically assess the evidence that is cited in support of these arguments. The results of our experiments provide little support for the idea that substantively different factors govern the patterns of acquisition, production and interpretation patterns of regular and irregular plural forms in compounds. Once frequency differences between regular and irregular plurals are accounted for, we find no evidence of any qualitative difference in the patterns of interpretation and production of regular and irregular plural nouns in compounds, in either adults or children. Accordingly, we suggest that the pattern of acquisition of both regular and irregular plurals in compounds is consistent with a simple account, in which children learn the conventions that govern plural compounding using evidence that is readily available in the distribution patterns of adult speech.     

Edmund Husserl＇s Political Praxis and Theoretical Reflections during World War I

Husserl the philosopher personally experienced World War I breaking out 100 years ago. Like most German and Austrian commoners, at the initial stage of the war, Husserl was extremely passionate for it. After undergoing the cruelty of war and losing many relatives and friends, he was once enmeshed in extreme confusion and disappointment, albeit he still made every effort to offer spiritual and ethical support to the soldiers at the front. Along with the proceeding of the war, he soon changed his views with respect to this war and confessed that more and deeper reflections were needed to address issues about problems of nationality, super-national ethics and about problems of wars relevant to them. He made philosophical theoretical reflections with regard to this war after it ended, and presented, eventually, requirements for himself： to be satisfied with taking the possibility of the practical activities of philosophy as the topic of philosophical theoretical study and to give up, in drastic fashion, the intention in such philosophical practices as providing political proposals and exerting political influences, ＂living purely as a scientific philosopher.＂     

＂I Effaced Myself＂ and ＂The Disappearance of the Subject＂： A Comparison between Zhuangzi and Jean Baudrillard＇s Anti-Subjectivism

In the chapter ＂The Adjustment of Controversies＂ in his eponymous work, Zhuangzi has the character Nanguo Ziqi declare ＂I effaced myself,＂ thereby holding that one can return to the state of naturalness only after breaking with the ＂self＂ that is in opposition to ＂objects,＂ abandoning his subject-object standpoint and entering a state of ＂effacement＂ wherein one fuses with the Dao. Coincidently, the French philosopher Jean Baudrillard also repeatedly stresses the ＂disappearance of the subject＂ in his later philosophy, trying to dissolve subject-centrism by means of a counterattack by the object wherein its logic would entrap the subject. Although they lived in different times, both Zhuangzi and Baudrillard note the same human predicament--the situation wherein the ＂I as subject＂ constantly obscures the ＂real I.＂ Their resolutions of the predicament are similar： both put their hopes in the dissolution of the ＂I＂ or self in subject-object relations, with Zhuangzi declaring ＂I effaced myself＇ and Baudrillard mooting the ＂disappearance of the subject.＂ They differ, however, on how to dissolve the ＂I＂ （myself）. Briefly, Zhuangzi advocates ＂effacing myself through the Dao,＂ that is, quitting one＇s ＂fixed mindset＂ and ＂egoism＂ and returning to the Dao by means of ＂forgetting＂ or ＂effacing＂; Baudrillard, on the other hand, proposes to ＂efface oneself through the object,＂ i.e., replace the supremacy of the subject with that of the object. Baudrillard＇s theory has often been criticized as pataphysics because of its nihilism without transcendence; in contrast, Zhuangzi＇s view, which construes the whole world as the unfolding of the Dao, seems more thought-provoking.     

Changes in processing of masked stimuli across early- and late-night sleep: a study on behavior and brain potentials

Sleep has proven to support the memory consolidation in many tasks including learning of perceptual skills. Explicit, conscious types of memory have been demonstrated to benefit particularly from slow-wave sleep (SWS), implicit, non-conscious types particularly from rapid eye movement (REM) sleep. By comparing the effects of early-night sleep, rich in SWS, and late-night sleep, rich in REM sleep, we aimed to separate the contribution of these two sleep stages in a metacontrast masking paradigm in which explicit and implicit aspects in perceptual learning could be assessed separately by stimulus identification and priming, respectively. We assumed that early sleep intervening between two sessions of task performance would specifically support stimulus identification, while late sleep would specifically support priming. Apart from overt behavior, event-related EEG potentials (ERPs) were measured to record the cortical mechanisms associated with behavioral changes across sleep. In contrast to our hypothesis, late-night sleep appeared to be more important for changes of behavior, both for stimulus identification, which tended to improve across late-night sleep, and for priming, with the increase of errors induced by masked stimuli correlating with the duration of REM sleep. ERP components proved sensitive to presence of target shapes in the masked stimuli and to their priming effects. Of these components, the N2 component, indicating processing of conflict, became larger across early-night sleep and was related to the duration of S4 sleep, the deepest substage of SWS containing particularly high portions of EEG slow waves. These findings suggest that sleep promotes perceptual learning primarily by its REM sleep portion, but indirectly also by way of improved action monitoring supported by deep slow-wave sleep.     

Academic Achievement Over 8 Years Among Children Who Met Modified Criteria for Attention-deficit/Hyperactivity Disorder at 4–6 Years of Age

The predictive validity of symptom criteria for different subtypes of ADHD among children who were impaired in at least one setting in early childhood was examined. Academic achievement was assessed seven times over 8 years in 125 children who met symptom criteria for ADHD at 4–6 years of age and in 130 demographically-matched non-referred comparison children. When intelligence and other confounds were controlled, children who met modified criteria for the predominantly inattentive subtype of ADHD in wave 1 had lower reading, spelling, and mathematics scores over time than both comparison children and children who met modified criteria for the other subtypes of ADHD. In some analyses, children who met modified criteria for the combined type had somewhat lower mathematics scores than comparison children. The robust academic deficits relative to intelligence in the inattentive group in this age range suggest either that inattention results in academic underachievement or that some children in the inattentive group have learning disabilities that cause secondary symptoms of inattention. Unexpectedly, wave 1 internalizing (anxiety and depression) symptoms independently predicted deficits in academic achievement controlling ADHD, intelligence, and other predictors.     

基于元认知的认知学习对动态能力影响的实证研究

通过实证研究勾勒出符合动态特征的元认知理论框架,提出构成元认知的6个要素,分别归为元认知策略、元认知调控和元认知知识三个维度.并借助结构方程模型重点分析了元认知、认知学习和动态能力的相关性,以及基于元认知的认知学习对动态能力演化的影响.