Reduced asymmetry in motor skill learning in left-handed compared to right-handed individuals

Hemispheric specialization for motor control influences how individuals perform and adapt to goal-directed movements. In contrast to adaptation, motor skill learning involves a process wherein one learns to synthesize novel movement capabilities in absence of perturbation such that they are performed with greater accuracy, consistency and efficiency. Here, we investigated manual asymmetry in acquisition and retention of a complex motor skill that requires speed and accuracy for optimal performance in right-handed and left-handed individuals. We further determined if degree of handedness influences motor skill learning. Ten right-handed (RH) and 10 left-handed (LH) adults practiced two distinct motor skills with their dominant or nondominant arms during separate sessions two–four weeks apart. Learning was quantified by changes in the speed–accuracy tradeoff function measured at baseline and one-day retention. Manual asymmetry was evident in the RH group but not the LH group. RH group demonstrated significantly greater skill improvement for their dominant-right hand than their nondominant-left hand. In contrast, for the LH group, both dominant and nondominant hands demonstrated comparable learning. Less strongly-LH individuals (lower EHI scores) exhibited more learning of their dominant hand. These results suggest that while hemispheric specialization influences motor skill learning, these effects may be influenced by handedness.     

面孔吸引力和配偶价值:进化心理学视角

面孔吸引力是对个体容貌的审美评价。根据进化心理学的观点,面孔吸引力是配偶价值的线索。这一假设是进化心理学视角下的面孔吸引力研究的前提所在。本文就涉及这一核心假设的研究进行梳理,重点关注影响面孔吸引力的形态特征与配偶价值的关系。这些形态特征包括面孔的性别二态性特征,面孔的波动性不对称特征以及面孔的肥胖特征。     

Speech presentation cues moderate frontal EEG asymmetry in socially withdrawn young adults

Socially withdrawn individuals display solitary behavior across wide contexts with both unfamiliar and familiar peers. This tendency to withdraw may be driven by either past or anticipated negative social encounters. In addition, socially withdrawn individuals often exhibit right frontal electroencephalogram (EEG) asymmetry at baseline and when under stress. In the current study we examined shifts in frontal EEG activity in young adults (N=41) at baseline, as they viewed either an anxiety-provoking or a benign speech video, and as they subsequently prepared for their own speech. Results indicated that right frontal EEG activity increased, relative to the left, only for socially withdrawn participants exposed to the anxious video. These results suggest that contextual affective cues may prime an individual's response to stress, particularly if they illustrate or substantiate an anticipated negative event.     

Sensitivity to lateral information on a perceptual word identification task in French third and fifth graders

This study aimed at examining sensitivity to lateral linguistic and nonlinguistic information in third and fifth grade readers. A word identification task with a threshold was used, and targets were displayed foveally with or without distractors. Sensitivity to lateral information was inferred from the deterioration of the rate of correct word identification when displayed with distractors. Results show that the two reader groups were sensitive to both right and left lateral information. The area of sensitivity to this information was more extended for the identification of easy words than difficult words. Examination of the detrimental effect of distractors suggests that in both third and fifth graders, the impact of lateral information on foveal processing is the result of a general distraction effect, but also of linguistic processing whose nature remains to be clarified.     

Menstrual cycle-related changes of functional cerebral asymmetries in fine motor coordination

Fluctuating sex hormone levels during the menstrual cycle have been shown to affect functional cerebral asymmetries in cognitive domains. These effects seem to result from the neuromodulatory properties of sex hormones and their metabolites on interhemispheric processing. The present study was carried out to investigate whether functional cerebral asymmetries in fine motor coordination as reflected by manual asymmetries are also susceptible to natural sex hormonal variations during the menstrual cycle. Sixteen right-handed women with a regular menstrual cycle performed a finger tapping paradigm consisting of two conditions (simple, sequential) during the low hormone menstrual phase and the high estrogen and progesterone luteal phase. To validate the luteal phase, saliva levels of free progesterone (P) were analysed using chemiluminescence assays. As expected, normally cycling women showed a substantial decrease in manual asymmetries in a more demanding sequential tapping condition involving four fingers compared with simple (repetitive) finger tapping. This reduction in the degree of dominant (right) hand manual asymmetries was evident during the luteal phase. During the menstrual phase, however, manual asymmetries were even reversed in direction, indicating a slight advantage in favour of the non-dominant (left) hand. These findings suggest that functional cerebral asymmetries in fine motor coordination are affected by sex hormonal changes during the menstrual cycle, probably via hormonal modulations of interhemispheric interaction.     

卫生经济学视野中的医患合谋

从分析医患合谋道德风险的影响因素入手,结合卫生经济学的供给曲线和需求曲线探讨产生医患合谋道德风险的原因和规避策略.发现医疗保险的供给方(保险机构)、医疗服务的提供方(医疗服务机构)和医疗保险的被保险方(医疗保险的消费者,即接受医疗服务的消费者或患者)三者之间信息不对称是导致道德风险的重要因素,保险基金风险更多是来自医疗服务提供方的道德风险.建议从建立信息公开制度,加强监督;加强激励,遏制道德风险;运用技术,规范行为三方面规范医疗服务提供方的行为.     

Biomechanical Study of Tandem Stance in Healthy Young Adults: Effects of Weight-Bearing and Limb Dominance

Postural strategies of healthy young adults to control tandem stance were investigated through the calculation of the relative contribution of the two loading-unloading (LU) and pressure-distribution (PD) mechanisms and the two legs for controlling the resultant center-of-pressure (CP_Res) displacements. Weight-bearing asymmetry and limb dominance were also studied. For antero-posterior and medio-lateral CP_Res displacements, LU and PD mechanisms mainly contribute, respectively. A significant LU contribution is nonetheless observed for medio-lateral control, due to a lateral gap between the CP positions under each foot despite a strict sagittal alignment for the two feet. Moreover, for medio-lateral control, the respective involvement of the two legs is related to the level of weight-bearing asymmetry, whereas the front leg mainly controls the antero-posterior sway. By specifying potential effects of body-weight asymmetry and limb dominance, to a better testing of patients with deficiencies in lateral sway control.     

Phallic Integration and Male Identity Development

The analytic setting as well as the analyst's initial communications unavoidably exert influence that may be perceived by the patient as a sexually tinged intrusion, which evokes questions about what the analyst wants. Together with the asymmetry of the analytic relationship, these phenomena uncannily bring to life a repressed relationship between infant and adult in which analogous stimuli constitute enigmas for the child. The theoretical understanding of Jean Laplanche of such enigmatic transference in terms of “primal seduction” is reviewed and clinical material is provided to illustrate Laplanche's ideas. The discussion addresses “recentralized” and “decentralized” aspects of sexuality. Primal seduction is discussed as including not only intrusion, but also qualities of stimulation and trust.     

Elementary school children’s attentional biases in physical and numerical space

Numbers are conceptualized spatially along a horizontal mental line. This view is supported by mounting evidence from healthy adults and patients with unilateral spatial neglect. Little is known about children's representation of numbers with respect to space. This study investigated elementary school children's directional biases in physical and numerical space to better understand the relation between space and number. We also examined the nature of spatial organization in numerical space. In two separate tasks, children (n = 57) were asked to bisect a physical line and verbally estimate the midpoint of number pairs. In general, results indicated leftward biases in both tasks, but the degree of deviation did not correlate between the tasks. In the number bisection task, leftward bias (underestimating the midpoint) increased as a function of numerical magnitude and interval between number pairs. In contrast, a rightward deviation was found for smaller number pairs. These findings suggest that different underlying spatial attentional mechanisms might be directed in physical and numerical space in young school children, which would be integrated in adulthood.     

Transforming valences through transitive inference: How are faces emotionally dissonant?

Information that is emotionally incongruous with self-concepts can produce feelings of unease. This implies that embedding incongruous information in newly formed relational structures would have little effect on their previous emotive properties. Alternatively, Relational Frame Theory highlights the importance of contextualized stimulus-stimulus relations, where the structure of a relational series is key in determining the function of its elements. To see whether series membership can mitigate ‘dissonance’ when a salient element is employed, the present investigation trained and tested a seven-term relational series (X>A>B>C>D>E>Y) using blurred faces as stimuli. Specifically, Stimuli X, A, B, D, E and Y were blurred unfamiliar faces and Stimulus C constituted of the participant’s own blurred face, assumed to be more salient than the former. To assess how the valences of the related stimuli were transformed by relational series membership, self-report ratings and electroencephalographic (EEG) recordings were collected before and after training the X>A>B>C>D>E>Y series. These pre vs. post contrasts revealed that, for unfamiliar faces, stimulus valence transformed as a function of relational structure. Conversely, the lack of difference in pre vs. post contrasts of Stimulus C, which maintained a high valence, suggest that relational series membership may not suffice to mitigate emotionally dissonant information.