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Forward bending and backward return of the human trunk in the sagittal plane are associated with a specific lumbopelvic rhythm, which consists of magnitude and timing aspects. In this study, the age-related differences in the timing aspect of lumbopelvic rhythm were investigated using the continuous relative phase method. Specifically, the mean absolute relative phase (MARP) between the thoracic and pelvic motions as well as variation in MARP under repetitive motions, denoted by deviation phase (DP), were characterized in sixty participants between 20 and 70 years old. MARP and DP were determined for trunk forward bending and backward return tasks with self-selected slow and fast paces. The MARP and DP were both smaller (p = 0.003, p < 0.001 respectively) in the older versus younger age participants with no gender-related difference. In fast versus slow pace task, the MARP was smaller (p < 0.001) only in forward bending, whereas the DP was smaller (p < 0.001) in both the forward bending and backward return. A more in-phase and more stable lumbopelvic rhythm denoted respectively by smaller MARP and DP in older versus younger individuals maybe a neuromuscular strategy to protect the lower back tissues from excessive strain, in order to reduce the risk of injury. 相似文献
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Changes in sleep patterns negatively influence some emotional responses, but their effects on facial expressiveness identification are unclear. To investigate these effects, 21 young, healthy, male volunteers of intermediate chronotype evaluated emotional expressiveness of faces depicting 6 basic emotions in 5 emotional gradients every 4?h over 36?h of continuous wakefulness. To measure attention and mood we used the Psychomotor Vigilance test and the Positive and Negative Affect Schedule Expanded, respectively. We found effects of emotional gradient for all types of emotions (100%?>?80%?>?60%?>?40%?>?20%) during all tested periods, with no indications of circadian effects. The only emotional rating to be affected was disgust, which was progressively blunted throughout the experiment. This effect did not parallel homeostatic and circadian changes in mood, alertness or attention. We conclude that identifying disgust on facial photographs is particularly sensitive to lack of sleep irrespective of sleep-induced changes in mood and attention in males. 相似文献
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时间加工是认知加工的内在属性。因此, 理解发生在知觉或更广泛的认知过程中的时间加工极为重要。为了应对中枢信息加工所面临的外部挑战, 大脑显然已形成了一些用于整合信息的特殊时间窗。已经发现, 其中一个时间窗介于数十毫秒的范围内, 它用于为意识活动产生必要的建构单元。来自反应时、时序阈限以及神经元结构振荡反应的研究为该时间窗的存在提供了实证证据。另一个时间窗的作用范围是2~3秒, 它用于产生“主观现在感”或作为使知觉体的标识保持不变的时间整合区间。支持该窗口存在的实验证据来自时距再现、两可图形、感觉运动同步以及神经生理学研究。还有一种时间窗以昼夜节律的形式存在。所有的心理和生理功能似乎都有着24小时的周期性变化。时间窗的紊乱会以神经或精神疾病的形式表现出来, 这恰恰表明了在基础研究之外对时间加工进行研究的重要性。 相似文献
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Oliver Stiedl Michael Meyer MD PhD 《Integrative psychological & behavioral science》2002,37(4):311-345
Non-linear fractal analysis of cardiac interbeat time series was performed in corticotropin-releasing factor receptor subtype
2 (CRFR2) deficient mice. Heart rate dynamics in mice constitutes a self-similar, scale-invariant, random fractal process
with persistent intrinsic long-range correlations and inverse power-law properties. We hypothesized that the sustained tachycardic
response elicited by intraperitoneal (ip) injection of human/rat CRF (h/rCRF) is mediated by CRFR2. In wildtype control animals,
heart rate was increased to about maximum levels (~ 750 bpm) while in CRFR2-deficient animals baseline values were retained
(~ 580 bpm). The tachycardic response elicited by ip-application is mediated by CRFR2 and is interpreted to result from sympathetic
stimulation. However, the functional integrity of CRFR2 would not present a prerequisite to maintaining the responsiveness
and resiliency of cardiac control to external environmental perturbations experimentally induced by extrinsic ip-application
of h/rCRF or under physiological conditions that may be associated with an increased peripheral release of CRF. Under stressful
physiological conditions achieved by novelty exposure, CRFR2 is not involved in the cardiodynamic regulation to external short-term
stress. While the hypothesis of involvement of CRFR2 in cardiac regulation upon pharmacological stimulation cannot be rejected,
the present findings suggest that the mechanism of action is by sympathetic stimulation, but would not unambiguously allow
to draw any conclusions as to the physiological role of CRFR2 in the control of cardiac dynamics. 相似文献
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This study explores differential processing of vocal and instrumental rhythms in short-term memory with three decision (same/different judgments) and one reproduction experiment. In the first experiment, memory performance declined for delayed versus immediate recall, with accuracy for the two rhythms being affected differently: Musicians performed better than non-musicians on clapstick but not on vocal rhythms, and musicians were better on vocal rhythms in the same than in the different condition. Results for the second experiment showed that concurrent sub-vocal articulation and finger-tapping differentially affected the two rhythms and same/different decisions, but produced no evidence for articulatory loop involvement in delayed decision tasks. In a third experiment, which tested rhythm reproduction, concurrent sub-vocal articulation decreased memory performance, with a stronger deleterious effect on the reproduction of vocal than of clapstick rhythms. This suggests that the articulatory loop may only be involved in delayed reproduction not in decision tasks. The fourth experiment tested whether differences between filled and empty rhythms (continuous vs. discontinuous sounds) can explain the different memorisation of vocal and clapstick rhythms. Though significant differences were found for empty and filled instrumental rhythms, the differences between vocal and clapstick can only be explained by considering additional voice specific features. 相似文献
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血压的生物节律与高血压的时间治疗学 总被引:3,自引:0,他引:3
人体血压的昼夜节律现象具有重要临床意义,高血压病更尤为如此。不同降压药物或不同时间用药对血压的昼夜节律产生不同的影响。高血压时间治疗学是根据疾病发生或发作的昼夜节律特征,通过调整投药时间及/或剂量、或应用特殊制剂,调整血液或组织中的药物浓度,从而增加疗效并减少或避免不良反应的发生。时间治疗学方法有助于以最小的医疗经济学及毒副反应代价获取最佳的治疗效果。 相似文献
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Time-space learning reflects an ability to represent in memory event-stimulus properties together with the place and time
of the event; a capacity well developed in birds. Homing pigeons were trained in an indoor octagonal arena to locate one food
goal in the morning and a different food goal in the late afternoon. The goals differed with respect to their angular/directional
relationship to an artificial light source located outside the arena. Further, the angular difference in reward position approximated
the displacement of the sun's azimuth that would occur during the same time period. The experimental birds quickly learned
the task, demonstrating the apparent ease with which birds can adopt an artificial light source to discriminate among alternative
spatial responses at different times of the day. However, a novel midday probe session following successful learning revealed
that the light source was interpreted as a stable landmark and not as a surrogate sun that would support compass orientation.
Probe sessions following a phase shift of the light–dark cycle revealed that the mechanism employed to make the temporal discrimination
was prevailingly based on an endogenous circadian rhythm and not an interval timing mechanism. 相似文献