Influence of Strategy on Muscle Activity During Impact Movements

Participants (N = 10) made flexions or extensions about the elbow. Movements either were pointing (i.e., self-terminated) or terminated by impact on a barrier. The author examined how the trajectory and the electromyographic (EMG) patterns varied according to the distance moved, the instruction provided concerning speed, or the type of termination. Variations in kinematics induced by changes in the target distance or the instruction regarding speed were the same for impact and pointing movements. In comparison with a pointing movement of similar distance and speed instruction, an impact movement (a) accelerated longer and reached a higher velocity, (b) had a longer agonist EMG burst, and (c) had a low level of contraction that started slightly after the agonist burst and continued throughout the movement but had little or no antagonist burst. Because the different types of movements required different forces from the muscles, there were systematic, task-specific differences in EMG patterns that reflected task-specific differences in central control. The results of this experiment demonstrate that impact movements share some of the rules used in the control of other tasks, such as pointing and reversing movements. The sharing is not imposed by mechanical or physiological constraints but, rather, represents the imposition of internal constraints.     

A Note on State Individual Differences in Accuracy of Response Imagery: Aftereffects and Reminiscence

In two sessions, separated by 7 days, subjects imagined themselves performing a tracking task under a massed practice schedule. After conditions of interpolated rest and no-rest, which were counterbalanced across sessions, subjects actually performed the tracking task. During imagery practice, subjects verbally reported the temporal component of the task. The temporal accuracy of verbal reports varied widely across subjects, but not within subjects. Furthermore, a performance gain was demonstrated as a function of interpolated rest versus no-rest (reminiscence effect). Finally, the accuracy of verbal reports predicted imagery aftereffects, but not reminiscence effects.     

The Influence of Motor Imagery on Postural Sway: Differential Effects of Type of Body Movement and Person Perspective

The present study examined the differential effects of kinesthetic imagery (first person perspective) and visual imagery (third person perspective) on postural sway during quiet standing. Based on an embodied cognition perspective, the authors predicted that kinesthetic imagery would lead to activations in movement-relevant motor systems to a greater degree than visual imagery. This prediction was tested among 30 participants who imagined various motor activities from different visual perspectives while standing on a strain gauge plate. The results showed that kinesthetic imagery of lower body movements, but not of upper body movements, had clear effects on postural parameters (sway path length and frequency contents of sway). Visual imagery, in contrast, had no reliable effects on postural activity. We also found that postural effects were not affected by the vividness of imagery. The results suggest that during kinesthetic motor imagery participants partially simulated (re-activated) the imagined movements, leading to unintentional postural adjustments. These findings are consistent with an embodied cognition perspective on motor imagery.     

心理健康的测量与评估:大学生与成人及住院病人的纵向横向研究

对国内有关大学生心理问题比一般成人更严重的研究结论提出了质疑。使用总量4268人的样本,应用自编的心理健康评定量表(PHS)进行了纵向与横向研究。研究发现,大学生人群与一般成人同期相比,心理问题并非更严重。5项分量表中3项(抑郁、焦虑、躯体化)成人却明显比大学生人群要高,另外两项(强迫和精神病性)二者没有显著差异。但是,10年后的大学生与10年前的大学生在所有分量表上均见非常显著的差异,说明10年的变迁中,大学生的心理问题有非常明显的增长趋势,日见复杂化,虽然不能说比成人更严重,但是也足够引起我们的高度重视。将不同人群样本的数据按心理障碍严重性进行排列,依次是:住院精神障碍患者、成人、大学生。     

健康人格研究述评

在适应现代生活的同时人们愈来愈重视人格健康问题,个体的健康人格状况一直受到学者们的关注.文章对国内外二十年来健康人格的理论和实证研究进展进行了系统综述.在此基础上,指出了健康人格研究领域存在的问题和将来进一步研究的方向.     

Age and Flexible Thinking: An Experimental Demonstration of the Beneficial Effects of Increased Cognitively Stimulating Activity on Fluid Intelligence in Healthy Older Adults

ABSTRACT

The disuse hypothesis of cognitive aging attributes decrements in fluid intelligence in older adults to reduced cognitively stimulating activity. This study experimentally tested the hypothesis that a period of increased mentally stimulating activities thus would enhance older adults' fluid intelligence performance. Participants (N?=?44, mean age 67.82) were administered pre- and post-test measures, including the fluid intelligence measure, Cattell's Culture Fair (CCF) test. Experimental participants engaged in diverse, novel, mentally stimulating activities for 10–12 weeks and were compared to a control condition. Results supported the hypothesis; the experimental group showed greater pre- to post-CCF gain than did controls (effect size d?=?0.56), with a similar gain on a spatial-perceptual task (WAIS-R Blocks). Even brief periods of increased cognitive stimulation can improve older adults' problem solving and flexible thinking.     

Combination Effects of Forced Mild Exercise and GABAB Receptor Agonist on Spatial Learning,Memory, and Motor Activity in Striatum Lesion Rats

Basal ganglia (BG) lesions cause impairments of different mammalian’s movement and cognition behaviors. Motor circuit impairment has a dominant role in the movement disorders. An inhibitory factor in BG is GABA neurotransmitter, which is released from striatum. Lesions in GABAergic neurons could trigger movement and cognition disorders. Previous evidence showed that GABA_B receptor agonist (Baclofen) administration in human improves movement disorders and exercise can improve neurodegenerative and cognitive decline; however, the effects of both Baclofen and mild forced treadmill exercise on movement disorders are not well known. The main objective of this study is to investigate the combined effects of mild forced treadmill exercise and microinjection of Baclofen in the internal Globus Pallidus on striatum lesion-induced impairments of spatial learning and motor activity. We used Morris water maze and open filed tests for studying spatial learning, and motor activity, respectively. Results showed that mild exercise and Baclofen microinjection could not lonely affect the spatial learning, and motor activity impairments while the combination of them could alleviate spatial learning, and motor activity impairments in striatum-lesion animals. Our results suggest that striatum lesion-induced memory and motor activity impairments can improve with combination interaction of GABA_B receptor agonist and exercise training.