Reinforcement-related neurons in the primate basal forebrain respond to the learned significance of task events rather than to the hedonic attributes of reward

The objective of this study was to determine if the responses of basal forebrain neurons are related to the cognitive processes necessary for the performance of behavioural tasks, or to the hedonic attributes of the reinforcers delivered to the monkey as

Gender effect on the right-left discrimination task in a sample of heroin-dependent patients

Rationale: Discriminating right from left is an everyday cognitive ability. Repeated exposure to certain drugs, such as heroin, can produce poor performance on many cognitive tasks. However, it is yet unclear whether drug abuse impairs the ability of right-left discrimination. Objectives: The aim of the present study is to examine whether the spatial ability measured by the right-left discrimination task can be affected by heroin abuse and whether such drug effect, if it exists, is gender related. Methods: A paper-and-pen test was used. The test consists of line drawings of a person with no arm, one arm, or both arms crossing the vertical body axis of the figure. The line drawings are viewed from the back, from the front, or randomly alternating between the back and front drawings. The subjects task is to mark which is the right or left hand in the figure as fast as possible. Results: A main finding in this study was that the ability to discriminate between left and right in visual space was impaired in heroin-dependent patients. Especially, heroin-dependent females performed poorer than control females in all conditions but heroin-dependent males only performed poorly in part of conditions. Conclusions: Recent heroin abuse impairs the ability of right-left discrimination and such impairment is gender related: heroin-dependent females demonstrated greater performance deficits than males.

Effects of exposure to 50 Hz magnetic field of 1 mT on the performance of detour learning task by chicks

In the present study, we examined the effects of exposure to an extremely low-frequency magnetic field of 1 mT intensity on learning and memory in Lohmann brown domestic chicks using detour learning task. These results show that 20 h/day exposure to a low

The stress experience dependent long-term depression disassociated with stress effect on spatial memory task

Behavioral stress can either block or facilitate memory and affect the induction of long-term potentiation (LTP) and long-term depression (LTD). However, the relevance of the stress experience-dependent long-term depression (SLTD) to spatial memory task is unknown. Here we have investigated the effects of acute and sub-acute elevated platform (EP) and foot shock (FS) stress on LTD induction in CA1 region of the hippocampus of anesthetized rats and spatial memory in Morris water maze. We found that LTD was facilitated by acute EP stress, but not by sub-acute EP stress that may be due to the fast adaptation of the animals to this naturalistic mild stress. However, FS stress, an inadaptable strong stress, facilitated LTD induction both in acute and sub-acute treatment. In addition, with the same stress protocols, acute EP stress impaired spatial memory but the sub-acute EP stressed animals performed the spatial memory task as well as the controls, may due to the same reason of adaptation. However, acute FS stress slightly impaired learning but sub-acute FS even enhanced memory retrieval. Our results showed that SLTD was disassociated with the effect of stress on memory task but might be related to stress experience-dependent form of aberrant memory. (C) 2003 Elsevier Science Ireland Ltd. and the Japan Neuroscience Society. All rights reserved.

Solvent impregnated resin prepared using task-specific ionic liquids for rare earth separation

A novel bifunctional task-specific ionic liquid (TSIL), i.e. [trialkylmethylammonium][sec-nonylphenoxy acetate] ([A336] [CA-100]) was impregnated on intermediate polarized XAD-7 resin, and the prepared solvent impreganated resin (SIR) was studied for rare earth (RE) separation. Adsorption ability of the SIR was indicated to be obviously higher than that prepared by [A336][NO3] because of the functional anion of [A336][CA-100]. Adsorption kinetics, adsorption isotherm, separation and desorption of the SIR were also studied.

基于初等运动的多机器人避碰及死锁预防

该文以一实际应用为背景提出了多移动机器人避碰及死锁预防算法 ,该算法将机器人的运行环境形式化地描述为初等运动集、冲突图、总任务集及机器人作业集 ,利用集合论、图论的有关方法及技术实现了多机器人间的避碰与死锁预防 .当机器人的运行环境改变时 ,只需要对相应的集合描述文件进行修改 ,而不用对程序做任何改动 .算法的另一个特点是利用避碰算法巧妙地完成了死锁预防 .仿真和实际运行证明了该算法高效可靠 .

工作投入的影响因素及其作用机制研究

Work engagement (WE) has recently become a fashionable term among Human Resource practitioners and Organizational Behavior researchers. However, academic research that has theoretically examined WE at the psychological level is limited, as is research on its place among other job attitude constructs that are used to describe employees at work, and its antecedents and consequences. This dissertation addresses a number of issues with regard to the discriminant validity of WE, the influences of WE and the mediating role of affective commitment, and the interaction effects of different job demands, job resources and personal resources on WE. The major findings are listed as follows: Firstly, the concept of WE is different from JB and job involvement (JI), and is more positively related to quality of employees’ work and life than the other two concepts. Specifically, WE is more related to employees’ creative performance than JB does; compared with JI, WE can better predict task performance, creative performance, organizational citizenship behavior (OCB), and life satisfaction; although both WE and JB cause work to family conflict, WE improves employees’ life satisfaction, while JB is deleterious to life satisfaction. Secondly, WE influences employees’ work and life directly or through the mediation effect of affective commitment. Specifically, WE reduces employees’ turnover intention and increase their OCBs by the the mediation effect of effective commitment. Furthermore, WE is positively related to task performance, creative performance, and life satisfaction directly. Thirdly, challenge job demands influence WE by the mediation effect of intrinsic motivation, and the impact of challenge job demands on WE is moderated by perceived supervisor support and growth needs. Specifically speaking, challenge job demands enhance employees’ intrinsic motivation, therefore boost WE. Employees with higher growth needs are more likely to be motivated by challenge job demands. In other words, the moderation effect of growth need is mediated by intrinsic motivation. In addition, those who perceive more supervisor support have higher level of WE when challenge job demands are high.

团队有效性：协作行为与作业特征作用机制研究

Organizations are increasingly turning to team-based structures to contend with the pressure of the increasing global competition, consolidation, innovation and need for diverse skills, expertise, and experiences. This ongoing transformation in the basic organization of work has captured the attention of researcher. And group and team research has become increasingly centered in the fields of organizational psychology and organizational behavior since the 1990s. A great deal empirical studies were conducted; a number of variables contributing to team effectiveness and several IPO models were summarized. But teamwork behaviors, the dynamic and adaptive interactions among team members during the task completion, were still very vague. So were the team task characteristics, an important input variable of the IPO models. The effects of team task characteristics and teamwork behaviors on team effectiveness were explored according to IPO model on the basis of the reviews on previous studies, the Hierarchical Conceptual Structure of Teamwork Behaviors (Rousseau et al.,2006), and the task characteristic theory(Hackman & Oldman, 1975). The questionnaire data from 479 team members and 110 team managers of 22 organizations were analyzed. The results indicate: A. Teamwork behaviors consist of 13 behavioral dimensions: team mission analysis, goal specification, planning, coordination, cooperation, information exchange, performance monitoring, backing-up behaviors, intra-team coaching, collaborative problem solving, team practice innovation, psychological support and integrative conflict management. The hierarchical conceptual structure was partly supported with five variable identified, i.e., preparation of work accomplishment, task-related collaborative behaviors, work assessment behaviors, team adjustment behaviors and the management of team maintenance. The formal four variables are in a sequential way. B. The task characteristic theory at individual level is applicable to the team level. This means that the team task characteristics consist of task variety, identity, significance, feedback, autonomy, interdependence. C. The correlations among task characteristics, teamwork behaviors and outcomes support the IPO model. The regulation of team performance mediated the effects of task meaningfulness and interdependence on team outcomes, with the direct effects of task meaningfulness on the preparation behaviors and the direct effects of interdependence on the task-related collaborative behaviors. The management of team maintenance mediated the effects of autonomy on team cohesion and satisfaction. The regulation of team performance has a direct effect on the team performance and the management of team maintenance. And the management of team maintenance has a direct effect on the team attitude and the regulation of team performance.

听觉想象的大脑表征

As a species of internal representation, how is mental imagery organized in the brain? There are two issues related to this question: the time course and the nature of mental imagery. On the nature of mental imagery, today's imagery debate is influenced by two opposing theories: (1) Pylyshyn’s propositional theory and (2) Kosslyn’s depictive representation theory. Behavioural studies indicated that imagery encodes properties of the physical world, such as the spacial and size information of the visual world. Neuroimaging and neuropsychological data indicated that sensory cortex; especially the primary sensory cortex, is involved in imagery. In visual modality, neuroimaging data further indicated that during visual imagery, spatial information is mapped in the primary visual, providing strong evidences for depictive theory. In the auditory modality, behavioural studies also indicated that auditory imagery represents loudness and pitch of sound; this kind of neuroimaging evidence, however, is absent. The aim of the present study was to investigate the time course of auditory imagery processing, and to provide the neuroimaging evidence that imaginal auditory representations encode loudness and pitch information, using the ERP method and a cue-imagery (S1)-S2 paradigm. The results revealed that imagery effects started with an enhancement of the P2, probably indexing the top-down allocation of attention to the imagery task; and continued into a more positive-going late positive potentials (LPC), probably reflecting the formation of auditory imagery. The amplitude of this LPC was inversely related to the pitch of the imagined sound, but directly related to the loudness of the imagined sound, which were consistent with auditory perception related N1 component, providing evidences that auditory imagery encodes pitch and loudness information. When the S2 showed difference in pitch of loudness from the previously imagined S1, the behavioral performance were significantly worse and accordingly a conflict related N2 was elicited; and the high conflict elicited greater N2 amplitude than low conflict condition, providing further evidences that imagery is analog of perception and can encode pitch and loudness information. The present study suggests that imagery starts with an mechanism of top-down allocation of attention to the imagery task; and continuing into the step of imagery formation during which the physical features of the imagined stimulus can be encoded, providing supports to Kosslyn’s depictive representation theory.