经颅直流电刺激提高记忆功能

经颅直流电刺激是最近复兴的非侵入性无创脑刺激方法, 具有轻便、廉价、较为安全的特点。经颅直流电刺激能产生一系列生理变化, 相比传统脑成像方法具有优势, 在工作记忆、陈述性记忆、程序性记忆上已有应用, 可与传统认知训练相结合。经颅直流电刺激虽然不能进行精确定位, 但是能够基于脑区影响个体认知加工过程。经颅直流电刺激在临床上可以作为治疗手段, 对健康人可以作为神经训练的方法, 在心理学领域具有良好的研究前景。     

基于面孔知觉的刻板印象激活两阶段模型

从个体建构研究视角出发, 考察了基于面孔知觉的刻板印象激活过程。实验一比较了性别分类判断、启动范式以及同时呈现范式下刻板印象匹配性判断三者所用反应时的差异, 结果发现, 后者显著地大于前二者, 且等于前二者之和; 面孔倒置呈现使同时呈现范式下刻板印象匹配判断的反应时和错误率显著增大, 但其对启动范式中刻板印象匹配判断的反应时和错误率没有影响。实验二基于同时呈现范式, 通过不同程度的面孔变形来操纵性别类别提取的难度, 更精确地探讨了基于面孔知觉的社会类别信息提取过程对刻板印象激活的影响, 结果表明, 随着从面孔中提取类别信息难度的增加, 刻板印象激活所用的反应时也逐渐增大。研究结果证实了研究者所提出的刻板印象激活两阶段模型, 即基于面孔知觉的社会类别提取阶段和刻板印象信息激活阶段, 证实社会类别激活和刻板印象信息激活是两个分离的过程, 以社会类别信息提取为目的的面孔知觉对刻板印象的激活有显著影响。     

关键字母法对英文词汇记忆效能的制约因素初步研究

通过干预范式和中介刺激法,选择89名初中一年级学生为被试,采用一系列自编的材料和工具,初步探讨了关键字母法对英文词汇记忆效能的制约因素.结果表明:(1)无论从短期看,还是从长期看.难以识别关键字母,会在一定程度上制约关键字母法的效能,不过,该因素的制约作用并不显著;(2)无论从短期看.还是从长期看,无论为准确的回忆,还是为大致的回忆,难以提取关键字母释义是制约关键字母法的显著因素.中介刺激法,作为本研究的突出特征,试图继承和发展维果茨基所创立的双莺刺激法.     

Elucidating the neural correlates of egoistic and moralistic self-enhancement

Self-enhancement is the biasing of one’s view of oneself in a positive direction. The brain correlates of self-enhancement remain unclear though it has been reported that the medial prefrontal cortex (MPFC) may be important for producing self-enhancing responses. Previous studies have not examined whether the neural correlates of self-enhancement depend on the particular domain in which individuals are enhancing themselves. Both moralistic and egoistic words were presented to participants while transcranial magnetic stimulation (TMS) was applied to the MPFC, precuneus or in a sham orientation. Participants were asked to make decisions as to the words describing themselves, some of which were positive and some of which were negative. It was found the MPFC TMS significantly disrupted egoistic self-enhancement when TMS was delivered to the MPFC. Judgments involving moralistic words were not influenced by TMS. These data provide further evidence that MPFC is involved in self-enhancement, and that the role of MPFC may be selective in this regard.     

道德直觉加工机制的理论构想

认知和情绪因素在道德判断中的作用机制是社会认知神经科学研究中最具争议的热点问题之一。本文认为, 人类拥有一种普遍性的道德直觉, 它是一种可能同时包含道德知识和情绪情感的自动化加工系统, 决定人们对一个道德违反情境作出快速的判断。据此, 本文就如何深入揭示道德直觉的加工机制提出了研究构想, 研究将首先采用经颅磁刺激技术, 探索当认知功能受抑制后人们的道德加工的特点, 初步探索道德直觉存在的可能性; 然后采用事件相关电位技术, 从外显和内隐两个维度上探讨道德直觉的时程加工机制; 最后采用侧向化运动准备电位指标, 进一步探索道德直觉和基本厌恶情绪的分离。     

Further evaluation of methods to identify matched stimulation

The effects of preferred stimulation on the vocal stereotypy of 2 individuals were evaluated in two experiments. The results of Experiment 1 showed that (a) the vocal stereotypy of both participants persisted in the absence of social consequences, (b) 1 participant manipulated toys that did and did not produce auditory stimulation, but only sound-producing toys decreased his vocal stereotypy, and (c) only noncontingent music decreased vocal stereotypy for the other participant, but sterotypy paradoxically increased when toys were presented with music. Using a three-component multiple schedule, the results of Experiment 2 showed that the vocal stereotypy of both participants remained below preintervention levels following the removal of auditory stimulation and that 1 participant's vocal stereotypy increased following the removal of contingent reprimands. These patterns suggest that auditory stimulation functioned as an abolishing operation for vocal stereotypy and reprimands functioned as an establishing operation for vocal stereotypy. Together, the two experiments provide a method for identifying alternative stimulation that may substitute for automatically reinforced behavior.     

Cortical Language Mapping in Epilepsy: A Critical Review

One challenge in dominant hemisphere epilepsy surgery is to remove sufficient epileptogenic tissue to achieve seizure freedom without compromising postoperative language function. Electrical stimulation mapping (ESM) of language was developed specifically to identify essential language cortex in pharmacologically intractable epilepsy patients undergoing left hemisphere resection of epileptogenic cortex. Surprisingly, the procedure remains unstandardized, and limited data support its clinical validity. Nevertheless, ESM for language mapping has likely minimized postoperative language decline in numerous patients, and has generated a wealth of data elucidating brain–language relations. This article reviews the literature on topographical patterns of language organization inferred from ESM, and the influence of patient characteristics on these patterns, including baseline ability level, age, gender, pathology, degree of language lateralization and bilingualism. Questions regarding clinical validity and limitations of ESM are discussed. Finally, recommendations for clinical practice are presented, and theoretical questions regarding ESM and the findings it has generated are considered.     

Electrical stimulation of the pedunculopontine tegmental nucleus in freely moving awake rats: time- and site-specific effects on two-way active avoidance conditioning

The pedunculopontine tegmental nucleus (PPTg) is involved in the regulation of thalamocortical transmission and of several functions related to ventral and dorsal striatal circuits. Stimulation of the PPTg in anesthetized animals increases cortical arousal, cortical acetylcholine release, bursting activity of mesopontine dopaminergic cells, and striatal dopamine release. It was hypothetized that PPTg stimulation could improve learning by enhancing cortical arousal and optimizing the activity of striatal circuits. We tested whether electrical stimulation (ES) of the PPTg, applied to freely-moving awake rats previously implanted with a chronic electrode, would improve the acquisition and/or the retention of two-way active avoidance conditioning, and whether this effect would depend on the specific PPTg region stimulated (anterior vs posterior) and on the time of ES: just before (pre-training) or after (post-training) each of three training sessions. The treatment consisted of 20 min of ES (0.2 ms pulses at 100 Hz; current intensity: 40-80 microA). The results showed that (1) this stimulation did not induce either any signs of distress nor abnormal behaviors, apart from some motor stereotyped behaviors that disappeared when current intensity was lowered; (2) pre-training ES applied to the anterior PPTg improved the acquisition of two-way active avoidance, (3) no learning improvement was found after either post-training ES of the anterior PPTg, or pre- and post-training ES of the posterior PPTg. The results give support to a role of PPTg in learning-related processes, and point to the existence of functional PPTg regions.     

The effects of reinforcer magnitude on timing in rats

The relation between reinforcer magnitude and timing behavior was studied using a peak procedure. Four rats received multiple consecutive sessions with both low and high levels of brain stimulation reward (BSR). Rats paused longer and had later start times during sessions when their responses were reinforced with low-magnitude BSR. When estimated by a symmetric Gaussian function, peak times also were earlier; when estimated by a better-fitting asymmetric Gaussian function or by analyzing individual trials, however, these peak-time changes were determined to reflect a mixture of large effects of BSR on start times and no effect on stop times. These results pose a significant dilemma for three major theories of timing (SET, MTS, and BeT), which all predict no effects for chronic manipulations of reinforcer magnitude. We conclude that increased reinforcer magnitude influences timing in two ways: through larger immediate after-effects that delay responding and through anticipatory effects that elicit earlier responding.     

The role of the right posterior parietal cortex in temporal order judgment

Perceived order of two consecutive stimuli may not correspond to the order of their physical onsets. Such a disagreement presumably results from a difference in the speed of stimulus processing toward central decision mechanisms. Since previous evidence suggests that the right posterior parietal cortex (PPC) plays a role in modulating the processing speed of a visual target, we applied single-pulse TMS over the region in 14 normal subjects, while they judged the temporal order of two consecutive visual stimuli. Stimulus-onset-asynchrony (SOA) randomly varied between -100 and 100 ms in 20-ms steps (with a positive SOA when a target appeared on the right hemi-field before the other on the left), and a point of subjective simultaneity was measured for individual subjects. TMS stimulation was time-locked at 50, 100, 150, and 200 ms after the onset of the first stimulus, and results in trials with TMS on right PPC were compared with those in trials without TMS. TMS over the right PPC delayed the detection of a visual target in the contralateral, i.e., left hemi-field by 24 (+/-7 SE) ms and 16 (+/-4 SE) ms, when the stimulation was given at 50 and 100 ms after the first target onset. In contrast, TMS on the left PPC was not effective. These results show that the right PPC is important in a timely detection of a target appearing on the left visual field, especially in competition with another target simultaneously appearing in the opposite field.