爱荷华博弈任务(IGT)与决策的认知神经机制

爱荷华博弈任务(IGT)是一项检查情感性决策机制的常用实验范式。据此, Damasio等人提出了躯体标记假设(SMH)解释情绪影响决策的神经生理机制。近期, 大量研究在IGT究竟是模糊决策还是风险决策、与情绪和认知的关系、与工作记忆和陈述性记忆的关系以及IGT的神经网络与分子遗传机制等方面积累了丰富资料。结果显示, IGT加工的早期由模糊决策主导, 情绪性躯体信号对引导决策选项的偏好可能起关键作用, 后期则倾向是一种风险决策, 认知评价和预期对选项偏向逐渐占优势; IGT与工作记忆的加工成分有相互重叠, 也需陈述性记忆的参与; IGT的加工不仅依赖于杏仁核、腹内侧前额皮层、眶额皮层等组成的情绪脑网络的活动, 还与背外侧前额皮层、海马、腹侧纹状体、岛叶皮层、辅助运动前区、扣带回皮层等许多脑区的活动有关; COMT和5-HTT的基因多态性会调节IGT相关的决策加工。总之, IGT是一项需要多重神经系统协同活动的决策加工任务, 且模糊与风险决策可能具有不同的遗传基础。     

Rapid acquisition of preference in concurrent chains: effects of d-amphetamine on sensitivity to reinforcement delay

The purpose of this study was to examine effects of d-amphetamine on choice controlled by reinforcement delay. Eight pigeons responded under a concurrent-chains procedure in which one terminal-link schedule was always fixed-interval 8 s, and the other terminal-link schedule changed from session to session between fixed-interval 4 s and fixed-interval 16 s according to a 31-step pseudorandom binary sequence. After sufficient exposure to these contingencies (at least once through the pseudorandom binary sequence), the pigeons acquired a preference for the shorter reinforcement delay within each session. Estimates of the sensitivity to reinforcement immediacy were similar to those obtained in previous studies. For all pigeons, at least one dose of d-amphetamine attenuated preference and, hence, decreased estimates of sensitivity to reinforcement immediacy; in most cases, this effect occurred without a change in overall response rates. In many cases, the reduced sensitivity to reinforcement delay produced by d-amphetamine resulted primarily from a decrease in the asymptotic level of preference achieved within the session; in some cases, d-amphetamine produced complete indifference. These findings suggest that a reduction in the sensitivity to reinforcement delay may be an important behavioral mechanism of the effects of psychomotor stimulants.     

高绩效工作系统负面影响的潜在机制

高绩效工作系统是一系列以提升组织绩效为目标的人力资源管理实践的集合或捆绑。已有研究发现高绩效工作系统也可能对员工产生负面影响。针对此问题, 本文首先澄清了高绩效工作系统的概念, 从管理理念分析其可能产生负面影响的原因。厘清了高绩效工作系统对组织和员工带来的不同效果, 从多元论的视角分析其负面影响的来源。基于工作要求−资源模型、自我决定理论、归因理论和过犹不及效应, 阐释高绩效工作系统对员工负面影响的内在机制。并进一步从个人和组织层面分析高绩效工作系统产生负面影响的边界条件。最后, 提出未来的研究方向和建议。     

条件化恐惧复发的动物模型及相关神经机制

创伤后应激障碍(PTSD)受到国内外普遍关注, 临床上常用的暴露疗法就是基于消退原理, 但经过治疗的患者复发率仍然很高, 这提示抑制复发可能是治疗创伤后应激障碍的关键问题。条件性恐惧复发的动物模型主要包括重建、续新和自发恢复, 但是对续新的研究最多。前人的研究结果表明, 恐惧复发具有异质性, 但海马、前额叶与杏仁核三大脑区或许构成了共同的神经基础。文章从脑区机制及药理干预方面进行了综述, 以期对基础研究和临床诊治提供参考。     

镜像神经元的意义

镜像神经元是一种感觉–运动神经元。它的典型特征是在动作观察和动作执行两个阶段皆被激活。多年来, 由于研究伦理的限制, 研究恒河猴时使用的单细胞电极植入方式无法应用于人类, 因而不能确定人类大脑皮层是否也存在着具有同样功能的神经细胞。但是通过脑成像技术, 神经科学家确定人类大脑皮层存在着具有相同或类似功能的脑区, 称为“镜像神经系统”。文章对镜像神经元及其人类镜像神经系统的意义进行了深入分析, 指出：(1)由于镜像机制把动作知觉和动作执行进行匹配, 观察者仅仅通过他人行为的知觉, 就激活了执行这一动作的神经环路, 产生了一种他人动作的具身模拟, 因而可以直接把握他人的行为意图; (2)镜像神经元所表现出来的那种动作知觉与动作执行的双重激活功能支持了身心一体说, 从方法论上证明了身心二元论的缺陷, 为身心的整体观提供了神经生物学的证据; (3)镜像神经机制把他人的动作与自己的运动系统相匹配, 以自身动作的神经环路对他人的动作做出回应, 促进了人际理解和沟通, 成为社会沟通的“神经桥梁”。     

技能学习与重复启动基本机制问题的探讨

关于技能学习与重复启动的基本机制问题在学术界存有很大的争议．对其进行探讨将会对从整体上考察程序性记忆的性质产生重要的影响。此文主要从函数形式、相关性和增减模式的理论分析,数字输入任务的计算模型．程序性记忆和学习的观点几个方面探讨了有关问题,说明技能学习与重复启动是程序性记忆的不同表现形式,它们有着相同的基本机制。     

Impaired long-term potentiation and enhanced neuronal excitability in the amygdala of CaV1.3 knockout mice

Previously, we demonstrated that mice in which the gene for the L-type voltage-gated calcium channel Ca_V1.3 is deleted (Ca_V1.3 knockout mice) exhibit an impaired ability to consolidate contextually-conditioned fear. Given that this form of Pavlovian fear conditioning is critically dependent on the basolateral complex of the amygdala (BLA), we were interested in the mechanisms by which Ca_V1.3 contributes to BLA neurophysiology. In the present study, we used in vitro amygdala slices prepared from Ca_V1.3 knockout mice and wild-type littermates to explore the role of Ca_V1.3 in long-term potentiation (LTP) and intrinsic neuronal excitability in the BLA. We found that LTP in the lateral nucleus (LA) of the BLA, induced by high-frequency stimulation of the external capsule, was significantly reduced in Ca_V1.3 knockout mice. Additionally, we found that BLA principal neurons from Ca_V1.3 knockout mice were hyperexcitable, exhibiting significant increases in firing rates and decreased interspike intervals in response to prolonged somatic depolarization. This aberrant increase in neuronal excitability appears to be at least in part due to a concomitant reduction in the slow component of the post-burst afterhyperpolarization. Together, these results demonstrate altered neuronal function in the BLA of Ca_V1.3 knockout mice which may account for the impaired ability of these mice to consolidate contextually-conditioned fear.     

两种自我保护机制：记忆忽视和自我免疫

当自我概念的稳定性受到威胁时,人们有时会采取自我保护手段来加以应对。在诸多自我保护方式中,记忆忽视加工是指个体在接触具威胁性的信息时进行选择性记忆,自然地忽视此类信息而不让其进入精加工,以消除该信息对自我概念的伤害;自我免疫加工是指个体通过对具威胁性信息的适宜操作界定来强调自己的优势能力,并重新评估自己的弱点,从而策略性地实现自我概念的稳定。文章从两种加工的认知机制角度来介绍和评述该领域的研究概况、研究方法与研究展望,借以引起对自我保护机制研究新进展的关注     

In vitro reinforcement of hippocampal bursting: a search for Skinner's atoms of behavior.

A novel "in vitro reinforcement" paradigm was used to investigate Skinner's (1953) hypotheses (a) that operant behavior is made up of infinitesimal "response elements" or "behavioral atoms" and (b) that these very small units, and not whole responses, are the functional units of reinforcement. Our tests are based on the assumption that behavioral atoms may plausibly be represented at the neural level by individual cellular responses. As a first approach, we attempted to reinforce the bursting responses of hippocampal units in a highly reduced brain-slice preparation with local micropressure applications of behaviorally reinforcing dopaminergic drugs. The same injections were administered independently of bursting to provide a "noncontingent" control for nonspecific stimulation or facilitation of firing. It was found that the bursting responses of individual CA1 pyramidal neurons may be progressively facilitated in a dose-related manner by response-contingent (but not noncontingent) injections of dopamine itself, the dopamine D1-preferring agonist SKF 82958, the D3-preferring agonist quinpirole, and the D2-like selective agonist (+)-4-propyl-9 hydroxynapthoxazine. These findings support the conclusion that unit bursting responses can be reinforced in vitro in hippocampal slices, and they further suggest that the same dopamine receptor subtypes are involved in both cellular and behavioral operant conditioning. The results thus provide indirect support for Skinner's atoms-of-behavior hypothesis.     

An empirical look at the Defence Mechanism Test (DMT) Stimulus effects

Based on a sample of non-clinical subjects (N=74) the study examines the Defence Mechanism Test (DMT) by focusing on when perceptual distortions, called ‘signs of defence’ in DMT terminology, occur (distribution in exposure duration), which part of the picture is involved (distribution in localisation), and which ‘signs’ go together (using correlation and factor analyses). The results disclosed that the occurrence of perceptual distortions (‘signs of defence’) was related to exposure duration (some ‘defences’ are more frequent at brief exposures, some others at longer exposure durations), and to localisation on the picture. The location of misperceptions to the central person (hero) or the peripheral person (pp) of the picture was the major explanatory principle for the distribution of ‘signs’ on factors. Rather than capturing psychodynamic defence mechanisms, which is the theoretical basis of the test, the analyses imply that the DMT seems to measure misperceptions which are a function of the localisation of persons on the stimulus picture and of exposure durations.