Episodic memory and the hippocampus: it's about time

Several recent studies have sought to develop animal models of episodic memory, the capacity to recollect unique personal experiences. However, these studies have not yet provided unambiguous evidence that this capacity is based on recollection of the learning episodes. A recent study that examined memory for the ordering of events within unique experiences, and demonstrated a critical and selective role for the hippocampus, suggests a new and promising model for neurobiological analyses of episodic memory.     

Deficits in prospective memory following damage to the medial subdivision of the mediodorsal thalamic nucleus

Identifying the neurocognitive mechanisms that lead individuals remembering to execute an intention at the right moment (prospective memory, PM) and how such mechanisms are influenced by the features of that intention is a fundamental theoretical challenge. In particular, the functional contribution of subcortical regions to PM is still unknown. This study was aimed at investigating the role of the medial subdivision of the mediodorsal thalamic nucleus (mMDT) in PM, with particular focus on the processes that are mediated by the projections from/to this structure. We analysed the performance of a patient (OG) with a right-sided lesion involving the mMDT in a series of PM tasks that varied for focality (i.e., overlapping of processes for the PM and ongoing tasks) and emotional valence of the stimuli, comparing the patient's performance with that of a control group. We found that the mMDT damage led to deficits in PM that were modulated by focality and emotional valence. OG indeed showed: a greater cost in the ongoing performance when a non-focal PM task was added; a slowing down in retrieving the intentions, in particular when these were associated with focal PM cues; an abnormal performance in the task with positive PM cues. Our findings provide evidence of a contribution of mMDT to PM and suggest a modulation of prefrontal-dependent strategic monitoring and a possible interaction with the limbic structures in the integration of emotion and PM processes. They also give support to the still controversial idea that connections with the perirhinal cortex mediate familiarity-based recognition.     

汉字属性匹配与大脑两半球协同活动

在识别汉字时,大脑两半球同时加工的作业成绩是否随加工阶段的增加而显出优势。本研究用汉字形、音、义三种属性分别相匹配的方法用用指定指定提取法,所得实验结果一致表明,形似材料双侧视野同时识别与单侧视野识别成绩无显著差别,而同音与近义材料则表现出双侧呈现显著优于单侧呈现的作业成绩。最后结合脑功能成像研究,对加工阶段影脑半球佃同活动的原因进行了讨论。     

Source Monitoring: ERP Evidence for Greater Reactivity to Nontarget Information in Older Adults

Event-Related Potentials (ERPs) were collected concurrently with stimulus presentation during a source monitoring task. Younger adults were less likely than older adults to make source monitoring errors and their ERP records showed far greater discrimination between target stimuli and familiar but nontarget foils. Older adults not only made more source errors but produced high amplitude late positivities to the nontarget foils even when these foils were correctly rejected. Under divided attention conditions, younger adults performance was similar to that of the older adults both behaviorally and electrophysiologically. These data illustrate the role that attentional resources play in the ability to inhibit response tendencies and suggest that age differences in source monitoring may be more related to attentional control than inefficiencies in the encoding of contextual information. As well, they suggest that the ERP late positivity may represent a more general response to item salience rather than serve as an index of recollection as is the current view.     

汉字识别中部件的频率效应

用整字识别、整合识别和部件识别任务探讨部件频率在汉字显示识别中的作用．实验一发现第一部件频率促进低频两部件合体字识别;实验二先后呈现合体字两组成部件并识别整字,第二部件频率有干扰作用;实验三识别合体字中的部件,部件频率有易化作用．部件在汉字识别中的易化和干扰作用受整字频率和结构类型的影响．     

Quantification of human confidence in functional relations

What makes people infer that two continuous-valued entities are functionally related? Involving factors influencing human confidence in the existence of a functional link between two supposed variables has not so far been discussed in function learning literature. By examining this problem and based on relevant results from cognitive psychology, I propose a hypothesis according to which human confidence in a link between cue and criterion is affected by three factors: The difficulty of functions, the level of noise in observed data, and the sample size. Here, the formalization of this hypothesis forms a novel mathematical model of function learning which can also be used for predictions; so the resulting model receives cue-criterion pairs of a supposed relation and produces two outputs: Confidence and predicting function. In an experiment, the performance of a computational implementation of the model is compared with human data. The results show that the model is successful in tracking changes in human confidence. A close correspondence between the predictions of the model and humans was also achieved.     

Differences in false recollection according to the cognitive reserve of healthy older people

We present an associative recognition experiment comparing three samples of healthy people (young people, older people with high cognitive reserve [HCR], and older people with low cognitive reserve [LCR], with each sample consisting of 40 people), manipulating stimuli repetition during the study phase. The results show significant differences among the three samples in their overall performance. However, these differences are not due to a different use of familiarity, but rather due to a different way of using recollection: although there are no differences in the hit rates between the HRC and LRC samples, the LCR group makes significantly more recollective false alarms than the HCR group. Moreover, repetition provokes an increase in the recollective false alarms in the LCR group, but this does not occur in the group of young people or in the HCR group. These findings are explained in terms of recollection-based monitoring errors and seem to provide support for the cognitive reserve hypothesis.     

The influence of emotion on face processing

According to the broaden-and-build theory, positive emotions broaden one's thought-action repertoire, which may manifest as a widened attentional scope in cognitive processing. The present study directly tests this hypothesis by examining the influences of induced emotions (positive, neutral and negative) on holistic processing of face (Experiment 1) and face discrimination (Experiment 2). In both experiments, emotions induced with images from the International Affective Picture System significantly interacted with face processing. That is, positive emotions engendered greater holistic face encoding in a composite-face task in Experiment 1 and more accurate face discrimination in Experiment 2, relative to the neutral condition. In contrast, negative emotions impaired holistic face encoding in the composite-face task and reduced face discrimination accuracy. Taken together, these results provide further support for the attentional broadening effect of positive affect by demonstrating that induced positive emotions facilitate holistic/configural processing.     

Shame,guilt, and facial emotion processing: initial evidence for a positive relationship between guilt-proneness and facial emotion recognition ability

Shame and guilt are closely related self-conscious emotions of negative affect that give rise to divergent self-regulatory and motivational behaviours. While guilt-proneness has demonstrated positive relationships with self-report measures of empathy and adaptive interpersonal functioning, shame-proneness tends to be unrelated or inversely related to empathy and is associated with interpersonal difficulties. At present, no research has examined relationships between shame and guilt-proneness with facial emotion recognition ability. Participants (N?=?363) completed measures of shame and guilt-proneness along with a facial emotion recognition task which assessed the ability to identify displays of anger, sadness, happiness, fear, disgust, and shame. Guilt-proneness was consistently positively associated with facial emotion recognition ability. In contrast, shame-proneness was unrelated to capacity for facial emotion recognition. Findings provide support for theory arguing that guilt and empathy operate synergistically and may also help explain the inverse relationship between guilt-proneness and propensity for aggressive behaviour.