视觉特征捆绑：基于时间同步还是基于相同空间位置？

通过操纵客体呈现的空间位置和时间顺序,来考察视觉特征捆绑是基于相同空间位置线索还是基于时间邻近线索。在两个实验中,给被试在固定的注视点位置（固定呈现条件）或在注视点上/下位置（变换呈现条件）快速地系列呈现刺激,记录靶子前后各两个时间位置（-2、-1、+1、+2）的错觉性结合（IC）率。结果发现,在固定呈现条件下,IC更多地出现在-1和+1的时间位置上;而在变换呈现条件下,错觉性结合更多地出现在-2和+2时间位置上。为了进一步排除特定实验范式的影响,在实验3中,我们采用特征分离范式,使被分离的刺激特征同时呈现在相同（相同位置同步）或不同（不同位置同步）的空间位置上。结果表明,这两种条件下的IC率无显著差异,这说明错觉性结合不受时间同步模式的影响。综上所述,来自三个实验的结果表明,时间范围内的特征捆绑机制是按空间位置,而不是按时间邻近,线索进行的：若特征的空间位置相同,时间邻近的特征才被捆绑起来;若空间位置不同,即使时间邻近的特征也不能被捆绑到一起。     

自尊水平、事件效价与时距对过去事件时距估计的影响

在西方文化背景下提出的时间自我评价理论认为,人们为了维护当前积极自尊,主观上会远离过去失败而亲近过去成功。本研究采用线段评估法,选取311名中国大学生被试,通过两个实验考察自尊水平、事件效价与时距对过去事件时距估计的影响,以检验该理论的文化普适性。结果表明:对过去事件的时距估计,自尊水平、事件效价及其交互作用在同一时距里均不存在显著差异;时距的主效应及其与事件效价的交互作用均显著,在负效价水平上存在显著时距差异,在正效价水平上无显著时距差异。研究结果不支持基于西方文化背景下的时间自我评价理论。     

Neural correlates of metonymy resolution

Metonymies are exemplary models for complex semantic association processes at the sentence level. We investigated processing of metonymies using event-related functional magnetic resonance imaging (fMRI).During an 1.5 Tesla fMRI scan, 14 healthy subjects (12 female) read 124 short German sentences with either literal (like “Africa is arid”), metonymic (“Africa is hungry”), or nonsense (“Africa is woollen”) content. Sentences were constructed so that they obey certain grammatical, semantic, and plausibility conditions and were matched for word frequency, semantic association, length and syntactic structure. We concentrated on metonymies that were not yet fossilised; we also examined a wide variety of metonymic readings.Reading metonymies relative to literal sentences revealed signal changes in a predominantly left-lateralised fronto-temporal network with maxima in the left and right inferior frontal as well as left middle temporal gyri. Left inferior frontal activation may reflect both inference processes and access to world knowledge during metonymy resolution.     

Speed and Rhythm Affect Temporal Structure of Variability in Reaching Poststroke: A Pilot Study

Temporal structure reveals the potential adaptive strategies employed during upper extremity movements. The authors compared the temporal structure of upper extremity joints under 3 different reaching conditions: preferred speed, fast speed, and reaching with rhythmic auditory cues in 10 individuals poststroke. They also investigated the temporal structure of these 3 reaching conditions in 8 healthy controls to aid in the interpretation of the observed patterns in the poststroke cohort. Approximate entropy (ApEn) was used to measure the temporal structure of the upper extremity joints. ApEn was similar between conditions in controls. After stroke, ApEn was significantly higher for shoulder, elbow, and wrist both at fast speed and with rhythmic cues compared with preferred speed. ApEn at index finger was significantly higher only with rhythmic cues compared with preferred speed. The authors propose that practice reaching at faster speed and with rhythmic cues as a component of rehabilitation interventions may enhance adaptability after stroke.     

Grasp-Based Functional Coupling Between Reach- and Grasp-Related Components of Forelimb Muscle Activity

How are appropriate combinations of forelimb muscles selected during reach-to-grasp movements in the presence of neuromotor redundancy and important task-related constraints? The authors tested whether grasp type or target location preferentially influence the selection and synergistic coupling between forelimb muscles during reach-to-grasp movements. Factor analysis applied to 14–20 forelimb electromyograms recorded from monkeys performing reach-to-grasp tasks revealed 4–6 muscle components that showed transport/preshape- or grasp-related features. Weighting coefficients of transport/preshape-related components demonstrated strongest similarities for reaches that shared the same grasp type rather than the same target location. Scaling coefficients of transport/preshape- and grasp-related components showed invariant temporal coupling. Thus, grasp type influenced strongly both transport/preshape- and grasp-related muscle components, giving rise to grasp-based functional coupling between forelimb muscles.     

记忆再巩固的时间动态性及其生物学机制

记忆巩固需经觉醒状态下的信息编码和睡眠状态下的巩固阶段两个过程。记忆再巩固理论认为记忆巩固是一个需要多次反复巩固的过程,即使已巩固的记忆也会在提取激活后变得不稳定, 需经再巩固才能重返稳定状态, 此过程需要新的蛋白质的合成。记忆再巩固具有较强的时间特征, 发生在记忆巩固之后, 依赖于蛋白质降解的去稳定化阶段和依赖于蛋白质合成的记忆再稳定阶段, 所持续的时间窗为6 h。不同类型的记忆是否引发记忆再巩固或消退行为, 取决于提取试次暴露所持续时间的长短。     

Rapid acquisition of choice and timing and the provenance of the terminal-link effect

Eight pigeons responded in a concurrent-chains procedure in which terminal-link schedules changed pseudorandomly across sessions. Pairs of terminal-link delays either summed to 15 s or to 45 s. Across sessions, the location of the shorter terminal link changed according to a pseudorandom binary sequence. On some terminal links, food was withheld to obtain start and stop times, measures of temporal control. Log initial-link response ratios stabilized within the first half of each session. Log response ratio was a monotonically-increasing but nonlinear function of programmed log terminal-link immediacy ratio. There was an effect of absolute terminal-link duration on log response ratio: For most subjects, preference for the relatively shorter terminal-link delay was stronger when absolute delays were long than when absolute delays were short. Polynomial regressions and model comparison showed that differences in degree of nonlinearity, not in sensitivity to log immediacy ratio, produced this effect. Temporal control of stop times was timescale invariant with scalar variability, but temporal control of start times was not consistent across subjects or terminal-link durations.     

Feedback related brain activity in a gambling task: A temporal analysis of EEG correlates

Lucchiari, C. & Pravettoni, G. (2010). Feedback related brain activity in a gambling task: A temporal analysis of EEG correlates. Scandinavian Journal of Psychology 51, 449–454. The pattern of neural correlates of feedback processing has been the subject of a number of studies, using both neuroimaging and electrophysiological recordings. A complex functional network was found to be activated after a choice in order to process a feedback and sustain an adaptive behavior. However, many aspects of this network are still unclear and further research is needed to better understand this process. We conducted an EEG study using a simple gambling task. Twenty three subjects participated to the study. We analyzed both EEG power spectrum and ERP components evoked by presentation of a feedback signal (money gain or loss) during a simple gambling task. Our data confirmed that a negative ERP component is present about 270 ms after feedback, particularly relevant following a choice with negative outcome. Furthermore, the theta and delta oscillatory activity seem to be correlated to a dynamic decision‐making process within specific cortical networks. In particular, theta activity showed a valence dependent development between 150 and 350 ms post‐feedback onset. Differently from previous studies (Cohen, Elger & Ranganath, 2007; Marco‐Pallares, Cucurell, Cunillera et al., 2008), we did not find any valence effect in beta range. However, our data are consistent with Christie and Tata (2009) , probably due to the nature of the gambling task used in both studies. In conclusion, our data, in line with some prior findings showed that the feedback related response is correlated to a complex pattern of cortical activation probably mediated by theta and delta activity.     

Arousal enhanced memory retention is eliminated following temporal lobe resection

The amygdala, situated in the anterior medial temporal lobe (MTL), is involved in the emotional enhancement of memory. The present study evaluated whether anterior MTL-resections attenuated arousal induced memory enhancement for pictures. Also, the effect of MTL-resections on response latencies at retrieval was assessed. Thirty-one patients with unilateral MTL-resections (17 left, 14 right) together with 16 controls participated in a forced choice memory task with pictorial stimuli varying in arousal. Response latencies increased with stimulus arousal in controls but not in patients. This was paralleled by attenuated recognition memory for moderately and highly arousing pictures in MTL-resectioned patients as compared to healthy controls. However, patients and controls did not differ in memory performance for non-arousing pictures. These results suggest that the MTL is necessary for arousal induced memory enhancement.