Temporal modulations of agonist and antagonist muscle activities accompanying improved performance of ballistic movements

Although many studies have examined performance improvements of ballistic movement through practice, it is still unclear how performance advances while maintaining maximum velocity, and how the accompanying triphasic electromyographic (EMG) activity is modified. The present study focused on the changes in triphasic EMG activity, i.e., the first agonist burst (AG1), the second agonist burst (AG2), and the antagonist burst (ANT), that accompanied decreases in movement time and error. Twelve healthy volunteers performed 100 ballistic wrist flexion movements in ten 10-trial sessions under the instruction to "maintain maximum velocity throughout the experiment and to stop the limb at the target as fast and accurately as possible". Kinematic parameters (position and velocity) and triphasic EMG activities from the agonist (flexor carpi radialis) and antagonist (extensor carpi radialis) muscles were recorded. Comparison of the results obtained from the first and the last 10 trials, revealed that movement time, movement error, and variability of amplitudes reduced with practice, and that maximum velocity and time to maximum velocity remained constant. EMG activities showed that AG1 and AG2 durations were reduced, whereas ANT duration did not change. Additionally, ANT and AG2 latencies were reduced. Integrated EMG of AG1 was significantly reduced as well. Analysis of the alpha angle (an index of the rate of recruitment of the motoneurons) showed that there was no change in either AG1 or AG2. Correlation analysis of alpha angles between these two bursts further revealed that the close relationship of AG1 and AG2 was kept constant through practice. These findings led to the conclusion that performance improvement in ballistic movement is mainly due to the temporal modulations of agonist and antagonist muscle activities when maximum velocity is kept constant. Presumably, a specific strategy is consistently applied during practice.     

情绪加工老化效应的神经机制

行为学研究发现,老年人对消极情绪的辨别、注意和记忆都有所下降,而对积极情绪并未表现出类似的现象。情绪加工老化效应的神经影像学研究发现,老年人在情绪加工过程中边缘系统（尤其杏仁核）的激活强度低于年轻人,但额叶皮层区域的激活却有所增强。研究者对该结果提出了两种假说,一种是功能代偿假说,另一种是策略改变假说。功能代偿假说认为老年人额叶皮层区域的激活增强是为了弥补边缘系统功能的下降,反映了大脑功能的代偿;策略改变假说认为老年人主动使用了不同于年轻人的策略,情绪加工方式的不同导致了两组人群大脑活动的差异。未来这方面研究可以从研究层面、研究方法、研究问题等方面逐步完善     

兴奋性氨基酸对猫怒叫反应的影响

为了提供猫“怒叫中枢”的神经元胞体参与怒叫反应的直接证据,本实验观察了“怒叫中枢”内注射谷氨酸单钠和海人酸对猫怒叫反应的影响。结果表明,“怒叫中抠”内注射谷氨酸单钠后,动物的呼吸加快,瞳孔明显扩大,电刺激引起叫反应的阈值明显降低。注射海人酸也可引起呼吸加快,瞳孔扩大,电刺激引起叫反应的阈值明显下降等反应。实验所用的动物中有3只动物,海人酸还可直接诱发叫反应。本实验提示,电刺激“怒叫中枢”引起的怒叫反应是神经元胞体兴奋的结果,而不是过路纤维兴奋的作用。     

Exploring Counselor-Client Agreement on Clients’ Work Capacity in Established and Consultative Dyads

Counselor-client agreement on the work capacity of clients living with serious mental illnesses informs the counseling relationship and facilitates accurate assessments of client eligibility for public programs. In this exploratory mixed-methods study, we assessed counselor-client agreement on clients’ work capacity in 61 established therapeutic dyads and compared it with 30 dyads involved in an initial assessment session. Intraclass correlation coefficients and mountain plots were used to examine counselor-client agreement. Results revealed moderate counselor-client agreement of work capacity for both dyads. Counselor interviews illuminated sources of discordance. These results have practical implications for assessing the work capacity of clients.     

下岗职工SCL-90的元分析

本文选取了9篇有关下岗职工SCL-90的研究成果进行元分析。元分析结果发现,下岗职工在“人际敏感”这个因子上没有影响外,在其余8个因子上都有很大的影响。这8个因子的平均效应值在0．21到0．66之间均属于中效应,说明我国下岗职工的心理健康状况比全国常     

Applicant Reactions to Personality Tests: Effects of Item Invasiveness and Face Validity

In a simulated employee selection exercise, two hundred and ten participants responded to a personality test that varied in terms of item invasiveness and item face validity. A third factor of empirical job-relatedness was manipulated via test instructions. Reactions to the test, the organization, and behavioral intentions about accepting a job offer were measured. Results indicated that item invasiveness and face validity interacted in the prediction of all dependent variables. Specifically, item invasiveness affected the dependent variables only when face validity was low. Implications for the use of personality tests and integrity tests were discussed.     

提高小学四年级学生情绪胜任力的干预研究

基于将情绪、认知和行为发展相整合的理念,试图通过团体干预活动,提高小学生的情绪胜任力。结果表明,6个系列干预活动能够有效提高小学四年级学生的情绪词汇量、情绪识别能力和情绪调节能力。团体内同伴提名和教师访谈显示,干预活动有助于促进学生的积极心境、自我控制能力和亲社会社交能力的发展,有助于减少攻击、同伴拒绝等适应不良行为。     

Glutamatergic activation of anterior cingulate cortex mediates the affective component of visceral pain memory in rats

Studies of both humans and animals suggest that anterior cingulate cortex (ACC) is important for processing pain perception. We identified that perigenul ACC (pACC) sensitization and enhanced visceral pain in a visceral hypersensitive rat in previous studies. Pain contains both sensory and affective dimensions. Teasing apart the mechanisms that control the neural pathways mediating pain affect and sensation in nociceptive behavioral response is a challenge. In this study, using a rodent visceral pain assay that combines the colorectal distension (CRD)-induced visceromotor response (VMR) with the conditioning place avoidance (CPA), we measured a learned behavior that directly reflects the affective component of visceral pain. When CRD was paired with a distinct environment context, the rats spent significantly less time in this compartment on the post-conditioning test days as compared with the pre-conditioning day. Effects were lasted for 14 days. Bilateral pACC lesion significantly reduced CPA scores without reducing acute visceral pain behaviors (CRD-induced VMR). Bilateral administration of non-NMDA receptor antagonist CNQX or NMDA receptor antagonist AP5 into the pACC decreased the CPA scores. AP5 or CNQX at dose of 400 mM produced about 70% inhibition of CRD-CPA in the day 1, 4 and 7, and completely abolished the CPA in the day 14 after conditioning. We concluded that neurons in the pACC are necessary for the "aversiveness" of visceral nociceptor stimulation. pACC activation is critical for the memory processing involved in long-term negative affective state and prediction of aversive stimuli by contextual cue.