Spinal Cord Circuits

Over the past decade, research at three different levels of sensorimotor control has revealed a degree of complexity that challenges traditional hypotheses regarding servocontrol of individual muscles: (a) The connectivity of spinal circuits is much more divergent and convergent than expected. (b) The normal and reflex-induced recruitment of individual muscles and compartments of muscles is more finely controlled than was noted previously. (c) The mechanical interactions among linked skeletal segments and their often multiarticular muscles are neither simple nor intuitively obvious. We have developed a mathematical model of the cat hind limb that permits us to examine the influence of individual muscles on posture and gait. We have used linear quadratic control theory to predict the optimal distribution of feedback from a hypothetical set of proprioceptors, given different assumptions about the behavioral goals of the animal. The changes in these predictions that result from changes in the structure and control objectives of the model may provide insights into the functions actually performed by the various circuits in the spinal cord.     

A study of the greater male variability hypothesis in creative thinking in Mainland China: Male superiority exists

This study tested the greater male variability hypothesis in creative thinking with a Chinese student sample in Mainland China. The Test for Creative Thinking-Drawing Production (TCT-DP) was administered to 627 Chinese adolescent boys (n = 332) and girls (n = 295). Results using the boy/girl variance ratio (VR) generally supported the hypothesis that boys have greater variability than girls in creativity test performance. However, results using the boy/girl ratios from different regions of the creativity score distribution revealed a pattern of male superiority. While boys significantly outnumbered girls in the higher extremes, girls tended to outnumber boys in the central region and the lower extremes. Results from an analysis of the means lent further support to the findings of male superiority. Plausible explanations for greater male variability and male superiority in Mainland China are proposed. The theoretical and practical implications of the findings are discussed.     

Age and emotion affect how we look at a face: Visual scan patterns differ for own-age versus other-age emotional faces

We investigated how age of faces and emotion expressed in faces affect young (n=30) and older (n=20) adults’ visual inspection while viewing faces and judging their expressions. Overall, expression identification was better for young than older faces, suggesting that interpreting expressions in young faces is easier than in older faces, even for older participants. Moreover, there were age-group differences in misattributions of expressions, in that young participants were more likely to label disgusted faces as angry, whereas older adults were more likely to label angry faces as disgusted. In addition to effects of emotion expressed in faces, age of faces affected visual inspection of faces: Both young and older participants spent more time looking at own-age than other-age faces, with longer looking at own-age faces predicting better own-age expression identification. Thus, cues used in expression identification may shift as a function of emotion and age of faces, in interaction with age of participants.     

Effect of strain rate on the compressive behaviour of a Zr56Al10.9Ni4.6Cu27.8Nb0.7 bulk metallic glass

We report the study of the effect of strain rate on the compressive behaviour of a Zr₅₆Al_10.9Ni_4.6Cu_27.8Nb_0.7 bulk metallic glass. The results indicated that both the strength and plasticity of the glass increase with increasing the strain rate up to 10^?5 s^?1, above which the strength and plasticity start to decrease. The enhanced mechanical properties under a strain rate of 10^?5 s^?1 are due to the emission/propagation rate of the shear bands being consistent with the strain rate.     

Waldo reveals cultural differences in return fixations

ABSTRACT

Humans routinely perform visual search towards targets to adapt to the environment. These sequences of ballistic eye movements are shaped by a combination of top–down and bottom–up factors. Recent research documented that human observers display cultural-specific fixation patterns in a range of visual processing tasks. In particular, eye movement strategies extracting information from faces clearly differs between Western Caucasian (WC) and East Asian (EA) observers. However, whether such cultural differences are also present for visual scene processing remains debated. To this aim, we recorded the eye movements of WC and EA observers while they were solving visual search problems parametrically varying in difficulty: Where’s Waldo. Both groups had a comparable familiarity with the Waldo books reaching a comparable level of accuracy in target detection. Both cultural groups also showed a comparable temporal effect on inhibition of return, with longer fixation durations when saccades were performed to a return location compared to other locations. Westerners, however, located Waldo faster than Easterners. Interestingly, this modulation of speed was likely related to differences occurring on the low-level mechanisms of spatial inhibition of return, with EA observers returning more often to previously visited locations than the WC observers. This suboptimal eye movement strategy in the Easterners might be engendered by their cultural perceptual bias consisting in? a greater use of extra-foveal information. Overall, our data point towards the existence of a subtle, but significant difference in the processing of visual scenes across observers from different cultures during active visual search.     

情绪性工作记忆对选择性注意的影响

选取大学本科生33名,采用情绪启动范式与再认范式相结合,要求被试依次完成情绪词识记、目标面孔性别判断及情绪词再认任务,探讨保存于工作记忆中的情绪性刺激对面孔性别判断任务的影响。结果显示:(1)在中性和恐惧情绪启动刺激条件下,被试对目标面孔性别判断的反应时要显著长于悲伤条件。(2)在愉悦情绪启动词条件下,线索提示有效性差异显著;在无效线索提示条件下,启动刺激的不同情绪效价差异显著。(3)对情绪面孔性别与被试性别一致性/非一致性两种条件下反应时对比发现,男、女被试在情绪面孔性别判断任务中均表现出异性相吸效应。综上所述,保存在工作记忆中情绪刺激会对面孔性别的识别产生自上而下的影响。     

生存加工的编码和提取双重优势效应:ERP证据

生存加工比控制条件有更好的记忆表现,产生稳定的记忆优势,这就是记忆生存优势.已有研究多采用行为学实验验证了此现象的存在,但没有确定该优势发生在记忆的何种阶段.本研究采用ERP技术和“间接学习-再认”实验范式,比较被试在生存情境、迁徙情境和愉悦判断中对词汇编码和提取过程的记忆加工,结果发现:在500-700ms时间段,生存情境的相继记忆效应显著大于迁徙情境和愉悦判断:在400-600ms时间段,生存情境的新旧效应显著大于迁徙情境和愉悦判断.表明生存加工具有编码和提取双重优势.     

小学生工作记忆与推理关系的实验研究

本实验以视觉同时呈现,在形近、音近、义近三种干扰下以再认方法和瑞文渐进推理测验探讨了小学生年级、性别、工作记忆与推理的关系。发现(I)小学生工作记忆与推理能力相关显著。(2)工作记忆和推理能力在小学阶段不存在性别差异。(3)年级和工作记忆是影响小学生推理能力的重要因素,但年级因素对推理能力的作用较工作记忆大。     

汉语语句重音的分类和分布

通过两个独立进行的重音标注实验对汉语语句重音的分类和分布进行了初步探讨。实验l是由60位普通被试参加的音节重音突显度的知觉实验。实验2是由本文三位作者参加的重音类别标注实验,在此实验中语句重音被划分为节奏重音和语义重音。实验2中对于语句重音的分类性标注结果得到了实验l中普通被试对音节重音突显度知觉结果的支持,这说明人们确实能够感知到两种不同类型的重音。实验结果还表明,节奏重音倾向于出现在较大韵律单元内的最末韵律词的末音节上,并且与适当的停延相伴生,语义重音的分布则与语句的韵律结构的关系不大。