653 research outputs found

    Mirror Adaptation in Sensory-Motor Simultaneity

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    Background: When one watches a sports game, one may feel her/his own muscles moving in synchrony with the player's. Such parallels between observed actions of others and one's own has been well supported in the latest progress in neuroscience, and coined “mirror system.” It is likely that due to such phenomena, we are able to learn motor skills just by observing an expert's performance. Yet it is unknown whether such indirect learning occurs only at higher cognitive levels, or also at basic sensorimotor levels where sensorimotor delay is compensated and the timing of sensory feedback is constantly calibrated. Methodology/Principal Findings: Here, we show that the subject's passive observation of an actor manipulating a computer mouse with delayed auditory feedback led to shifts in subjective simultaneity of self mouse manipulation and auditory stimulus in the observing subjects. Likewise, self adaptation to the delayed feedback modulated the simultaneity judgment of the other subjects manipulating a mouse and an auditory stimulus. Meanwhile, subjective simultaneity of a simple visual disc and the auditory stimulus (flash test) was not affected by observation of an actor nor self-adaptation. Conclusions/Significance: The lack of shift in the flash test for both conditions indicates that the recalibration transfer is specific to the action domain, and is not due to a general sensory adaptation. This points to the involvement of a system for the temporal monitoring of actions, one that processes both one's own actions and those of others

    Motion of the Tippe Top : Gyroscopic Balance Condition and Stability

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    We reexamine a very classical problem, the spinning behavior of the tippe top on a horizontal table. The analysis is made for an eccentric sphere version of the tippe top, assuming a modified Coulomb law for the sliding friction, which is a continuous function of the slip velocity vP\vec v_P at the point of contact and vanishes at vP=0\vec v_P=0. We study the relevance of the gyroscopic balance condition (GBC), which was discovered to hold for a rapidly spinning hard-boiled egg by Moffatt and Shimomura, to the inversion phenomenon of the tippe top. We introduce a variable ξ\xi so that ξ=0\xi=0 corresponds to the GBC and analyze the behavior of ξ\xi. Contrary to the case of the spinning egg, the GBC for the tippe top is not fulfilled initially. But we find from simulation that for those tippe tops which will turn over, the GBC will soon be satisfied approximately. It is shown that the GBC and the geometry lead to the classification of tippe tops into three groups: The tippe tops of Group I never flip over however large a spin they are given. Those of Group II show a complete inversion and the tippe tops of Group III tend to turn over up to a certain inclination angle θf\theta_f such that θf<π\theta_f<\pi, when they are spun sufficiently rapidly. There exist three steady states for the spinning motion of the tippe top. Giving a new criterion for stability, we examine the stability of these states in terms of the initial spin velocity n0n_0. And we obtain a critical value ncn_c of the initial spin which is required for the tippe top of Group II to flip over up to the completely inverted position.Comment: 52 pages, 11 figures, to be published in SIAM Journal on Applied Dynamical Syste

    Reversal Rate of Clustering of Cardiovascular Disease Risk Factors of Metabolic Syndrome in the General Population: The Niigata Preventive Medicine Study

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    The reversal rate from clustering of cardiovascular disease (CVD) risk factors—components of the metabolic syndrome (MetS) is not known. Methods and Results. Among 35,534 subjects who received the annual health examinations at the NiigataHealth Foundation (Niigata, Japan), 4,911 subjects had clustering of 3 or more of the following CVD risk factors: (1) body mass index (BMI) ≥25 Kg/m2, (2) blood pressure ≥130 mm Hg in systolic and/or ≥85 mm Hg in diastolic, (3) triglycerides ≥150 mg/dL, (4) high-density lipoprotein cholesterol ≤40 mg/dL in men, ≤50 mg/dL in women, and (5) fasting blood glucose ≥100 mg/dL. After 5 years 1,929 subjects had a reversal of clustering (39.4%). A reversal occurred more often in males. The subjects with a reversal of clustering had milder level of each risk factor and a smaller number of risk factors, while BMI was associated with the least chance of a reversal. Conclusion. We concluded that a reversal of clustering CVD risk factors is possible in 4/10 subjects over a 5-year period by habitual or medical interventions. Gender and each CVD risk factor affected the reversal rate adversely, and BMI was associated with the least chance of a reversal

    Judgments of Facial Attractiveness as A Dynamic Combination of Internal/External Parts

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    Although the importance of facial attractiveness has been widely researched, how attractiveness of internal/external facial parts and whole interacts in a time course of attractiveness judgment is still unclear. In our research, visual information integration in the facial attractiveness judgment has been investigated in a series of psychological experiments in which presentation of facial images to be evaluated their attractiveness was constrained spatially and/or temporally. Attractiveness evaluation of briefly-presented facial images demonstrated that 1) contribution of the eyes to the whole facial attractiveness judgment remains high even after short exposure duration as 20 milliseconds to the face, while contribution of other facial parts changed over time, and 2) either the gaze of the face is directed to or averted from the evaluator affected the dynamic integration of facial parts information to the judgments of whole facial attractiveness. Different experiments examining the influence of external feature on the perceived facial attractiveness revealed the mutual, but not symmetrical influence between facial attractiveness and hair attractiveness. These findings together suggest the dynamic feature of facial attractiveness judgment where information from internal/external features is integrated over the time while it is affected by social cue such as gaze direction of the face

    Judgments of Facial Attractiveness as A Dynamic Combination of Internal/External Parts

    Get PDF
    Although the importance of facial attractiveness has been widely researched, how attractiveness of internal/external facial parts and whole interacts in a time course of attractiveness judgment is still unclear. In our research, visual information integration in the facial attractiveness judgment has been investigated in a series of psychological experiments in which presentation of facial images to be evaluated their attractiveness was constrained spatially and/or temporally. Attractiveness evaluation of briefly-presented facial images demonstrated that 1) contribution of the eyes to the whole facial attractiveness judgment remains high even after short exposure duration as 20 milliseconds to the face, while contribution of other facial parts changed over time, and 2) either the gaze of the face is directed to or averted from the evaluator affected the dynamic integration of facial parts information to the judgments of whole facial attractiveness. Different experiments examining the influence of external feature on the perceived facial attractiveness revealed the mutual, but not symmetrical influence between facial attractiveness and hair attractiveness. These findings together suggest the dynamic feature of facial attractiveness judgment where information from internal/external features is integrated over the time while it is affected by social cue such as gaze direction of the face
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