Effects of rodent prefrontal lesions on object-based, visual scene memory

It has been suggested that certain prefrontal areas contribute to a neural circuit that mediates visual object memory. Using a successive go/no-go visual scene discrimination task, object-based long-term memory was assessed in two rodent prefrontal regions. Rewarded trials consisted of a standard scene of four toy objects placed over baited food wells. The objects and their locations composing the standard scene remained constant for the duration of the study. Trials in which one of the standard scene objects was replaced with a novel object were not rewarded. Following the establishment of a significant difference between latency to approach the rewarded standard scene compared to latency to approach non-rewarded scenes, quinolinic acid or control vehicle was infused into either the prelimbic and infralimbic cortices or the anterior cingulate cortex. Following a 1 week recovery period, subjects were retested. Animals with prelimbic/infralimbic cortex lesions displayed a profound and sustained deficit, whereas, animals with anterior cingulate cortex lesions showed a slight initial impairment but eventually recovered. Both lesion groups acquired a simple single object discrimination task as quickly as controls indicating that the deficits on the original scene discrimination task were not due to motivational, response inhibition, or perceptual problems.     

A model of episodic memory: Mental time travel along encoded trajectories using grid cells

The definition of episodic memory includes the concept of mental time travel: the ability to re-experience a previously experienced trajectory through continuous dimensions of space and time, and to recall specific events or stimuli along this trajectory. Lesions of the hippocampus and entorhinal cortex impair human episodic memory function and impair rat performance in tasks that could be solved by retrieval of trajectories. Recent physiological data suggests a novel model for encoding and retrieval of trajectories, and for associating specific stimuli with specific positions along the trajectory. During encoding in the model, external input drives the activity of head direction cells. Entorhinal grid cells integrate the head direction input to update an internal representation of location, and drive hippocampal place cells. Trajectories are encoded by Hebbian modification of excitatory synaptic connections between hippocampal place cells and head direction cells driven by external action. Associations are also formed between hippocampal cells and sensory stimuli. During retrieval, a sensory input cue activates hippocampal cells that drive head direction activity via previously modified synapses. Persistent spiking of head direction cells maintains the direction and speed of the action, updating the activity of entorhinal grid cells that thereby further update place cell activity. Additional cells, termed arc length cells, provide coding of trajectory segments based on the one-dimensional arc length from the context of prior actions or states, overcoming ambiguity where the overlap of trajectory segments causes multiple head directions to be associated with one place. These mechanisms allow retrieval of complex, self-crossing trajectories as continuous curves through space and time.     

Individuals differ in the attentional blink: Mental speed and intra-subject stability matter

The failure to correctly report two targets (“T₁”, “T₂”) that follow each other in close temporal proximity has been called the “attentional blink” (AB). The AB has, so far, mainly been studied using experimental approaches. The present studies investigated individual differences in AB performance, revealing (among further findings) a high positive correlation between the accuracies of detecting the two targets correctly (r = 0.69); and between T₂∣T₁ accuracy and psychometric intelligence (0.41 ≤ r ≤ 0.43) and RT variability in short-term and working memory (− 0.38 ≤ r ≤ − 0.45). Together, these results support important aspects of major theoretical accounts of the AB from an individual differences perspective and introduce intelligence and intra-subject stability as contributing factors in AB performance.     

Individual differences in emotional intelligence and incidental memory of words1

Participants were required to complete the Japanese version of the Emotional Skills and Competence Questionnaire ( Toyota, Morita, & Tak?i?, 2007 ) to assess their level of emotional intelligence. Then they were asked to rate the pleasantness of an episode that each target reminded them of, followed by unexpected free recall tests. Participants with high emotional intelligence recalled targets with pleasant, neutral, and unpleasant episodes equally. However, for participants with low emotional intelligence, targets with neutral episodes were recalled less than those with pleasant or unpleasant ones. These results were interpreted as showing that the level of emotional intelligence determined the effectiveness of neutral episodes on targets as retrieval cues.     

听觉后见之明偏差的实验研究

后见之明偏差是一种人类认知自我中心。后见之明偏差的研究具有重大的理论价值和应用价值,尤其是其应用价值更不容低估。研究1采用回忆型和假定型研究范式考察听觉领域是否存在后见之明偏差;研究2采用回忆型研究范式,从需要角度考察奖励性动机对去除听觉后见之明偏差的作用。研究发现:听觉领域存在后见之明偏差;两种研究范式的后见之明偏差不存在差异;奖励性动机并不能消除听觉后见之明偏差。     

Assessment of working memory components at 6years of age as predictors of reading achievements a year later

The ability of working memory skills (measured by tasks assessing all four working memory components), IQ, language, phonological awareness, literacy, rapid naming, and speed of processing at 6 years of age, before reading was taught, to predict reading abilities (decoding, reading comprehension, and reading time) a year later was examined in 97 children. Among all working memory components, phonological complex memory contributed most to predicting all three reading abilities. A capacity measure of phonological complex memory, based on passing a minimum threshold in those tasks, contributed to the explained variance of decoding and reading comprehension. Findings suggest that a minimal ability of phonological complex memory is necessary for children to attain a normal reading level. Adding assessment of phonological complex memory, before formal teaching of reading begins, to more common measures might better estimate children’s likelihood of future academic success.     

环境雌激素双酚A对成年小鼠学习记忆和突触结构的影响*

双酚A (bisphenol, BPA)是一种广泛存在的环境内分泌干扰物,它可与雌激素受体结合干扰内源性雌激素对中枢神经系统的调控作用。本研究通过将10周龄小鼠灌胃染毒BPA (0.4、4、40 mg/kg/day)3个月,研究长期BPA暴露对成年小鼠记忆行为和突触可塑性的影响。开场行为测试结果表明, BPA (0.4、4、40 mg/kg/day)增加雄性的站立次数和理毛频率, BPA (4 mg/kg/day)却显著减少雌鼠的站立次数。水迷宫和被动回避行为模型检测显示, BPA主要损伤雄鼠的空间学习记忆和被动回避记忆。通过制备海马CA1区超薄切片后,电镜观测发现, BPA (0.4、40 mg/kg/day)暴露降低雄鼠海马CA1区突触数密度,缩短雄鼠突触前活性带长度,减小雄鼠突触后致密体(PSD)厚度,增加雄鼠突触间隙宽度。进一步用Western blot方法检测突触前、后的标志性蛋白Synapsin I和PSD95以及兴奋性氨基酸NMDA受体NR1亚基和AMPA受体GluR1亚基蛋白的表达,发现BPA暴露致雄鼠Synapsin I、PSD95、NR1蛋白表达水平下调。而BPA对雌鼠的记忆行为、突触形态、突触蛋白和受体蛋白均没有明显作用。以上结果提示长期B PA暴露性别特异性地影响成年小鼠的活动性和探究行为,损伤雄鼠的学习记忆,这些作用可能通过下调突触蛋白和NMDA受体的表达而负性影响突触结构可塑性,最终影响雄鼠的学习记忆功能。     

Language aptitude for pronunciation in advanced second language (L2) Learners: Behavioural predictors and neural substrates

Individual differences in second language (L2) aptitude have been assumed to depend upon a variety of cognitive and personality factors. Especially, the cognitive factor phonological working memory has been conceptualised as language learning device. However, strong associations between phonological working memory and L2 aptitude have been previously found in early-stage learners only, not in advanced learners. The current study aimed at investigating the behavioural and neurobiological predictors of advanced L2 learning. Our behavioural results showed that phonetic coding ability and empathy, but not phonological working memory, predict L2 pronunciation aptitude in advanced learners. Second, functional neuroimaging revealed this behavioural trait to be correlated with hemodynamic responses of the cerebral network of speech motor control and auditory-perceptual areas. We suggest that the acquisition of L2 pronunciation aptitude is a dynamic process, requiring a variety of neural resources at different processing stages over time.     

The effects of relationship context and modality on ratings of funniness

There is evidence to suggest that humour is an important part of mate choice and that humour may serve as an indicator of genetic quality. The current study investigated how rated funniness from a video clip was related to an individual’s attractiveness as a short-term or long-term partner. We additionally tested for the presence of an attractiveness halo effect on humour ratings by comparing ratings of funniness from video clips, audio-only presentations, and photographs. We found that funniness was most strongly correlated with attractiveness for short-term relationships, especially in videos of males. We also found that attractiveness was related to funniness ratings differently across video, audio-only clips, and photographs. Relative to their rated funniness in the audio-only condition, with no appearance cues, attractive individuals were rated as funnier in video clips than less attractive individuals. An additional study demonstrated that ratings of flirtatiousness and funniness were strongly correlated. Perceived similarity between producing humour and flirting may explain why humour is more preferable in a short-term partner as flirting may be seen to signal proceptivity. The effects of attractiveness on humour judgement may also be explained by an association with flirtation as flirting may be most enjoyable when directed by attractive individuals.     

Gender differences in autobiographical memory: Developmental and methodological considerations

Gender differences have surfaced in inconsistent ways in autobiographical memory studies. When apparent, researchers find gender differences such that women report more vivid memory experiences than men and women include more details about emotions, about other people, and about the meaningfulness of their memories. Specifically, females include more emotion, more elaboration, and a greater sense of connectedness to others in their narratives, and we consider the possible connection between these tendencies and women’s advantage on a number of autobiographical and episodic memory tasks. However, not all studies of autobiographical memory find gender differences. We propose that gender differences in autobiographical memory development and interpersonal socialization contribute to the differences found, and that gender differences can be attributed, at least in part, to the influence of conversations with parents when autobiographical memory skills are developing. An examination of studies in which gender differences are not found suggests that specific instructions, context, gender salience, and the type of autobiographical memory measure used can mitigate gender differences. We conclude by outlining future directions for research, including longitudinal studies and experiments designed to systematically examine gender in autobiographical memory for its own sake.