条件推理中否定前件下信念偏差发生阶段的ERP研究

以日常生活中的条件推理语句为实验材料,采用大、小前提和结论依次呈现的“推断-判断”范式,利用事件相关电位(event-related brain potential, ERP)技术探讨了条件推理中否定前件下信念偏差效应的脑内时程动态变化。结果发现：在行为反应上,较信念促进,信念阻碍下的正确率更低反应时更长;在脑电上,两条件(信念阻碍和信念促进)诱发的ERP波形仅在大前提加工阶段出现明显的分离。这表明该推理下的信念偏差效应可能早在对大前提的语义表征阶段就已发生。     

Event-related potential practice effects on the Paced Auditory Serial Addition Test (PASAT)

Practice can change the nature and quality of a stimulus-response relationship. The current study observed the effects of repeated administration of the Paced Auditory Serial Addition Test (PASAT) in 12 healthy individuals, in an effort to establish distinct profiles associated with novel and practiced processing. Over four training sessions the mean number of correct responses on this demanding test of attention significantly improved and was approaching ceiling for most task conditions. Behavioural improvements were associated with significantly reduced amplitude of late Processing Negativity, a frontally distributed component of the event-related potential waveform associated with voluntary, limited-capacity activity within higher-order attentional systems. These results suggest that PASAT performance became more efficient as practice seemingly eased the strategic planning and coordination requirements the task places on frontally-mediated executive attention resources. The findings of the current study extend our understanding of the functional and behavioural mechanisms underlying the effects of practice.     

Detecting concealed information using feedback related event-related brain potentials

Employing an event-related potential (ERP)-based concealed information test (CIT), the present study investigated (1) the neurocognitive processes when people received feedbacks regarding their deceptive/truthful responses and (2) whether such feedback-related ERP activities can be used to detect concealed information above and beyond the recognition-related P300. During the CIT, participants were presented with rare, meaningful probes (their own names) embedded within a series of frequent yet meaningless irrelevants (others’ names). Participants were instructed to deny their recognition of the probes. Critically, following participants’ responses, they were provided with feedbacks regarding whether they succeeded or failed in the CIT. Replicating previous ERP-based CITs, we found a larger P300 elicited by probe compared to irrelevant. Regarding feedback-related ERPs, a temporospatial Principle Component Analyses found two ERP components that were not only sensitive to feedback manipulations but also can discriminate probe from irrelevant: an earlier, central-distributed positivity that was elicited by “success” feedbacks peaked around 219 ms; and a later, right central-distributed positivity that was also elicited by “success” feedbacks, peaked around 400 ms. Importantly, the feedback ERPs were not correlated with P300 that was elicited by probe/irrelevant, suggesting that these two ERPs reflect independent processes underlying memory concealment. These findings illustrate the feasibility and promise of using feedback-related ERPs to detect concealed memory and thus deception.     

The temporal dynamics of visual object priming

Priming reflects an important means of learning that is mediated by implicit memory. Importantly, priming occurs for previously viewed objects (item-specific priming) and their category relatives (category-wide priming). Two distinct neural mechanisms are known to mediate priming, including the sharpening of a neural object representation and the retrieval of stimulus–response mappings. Here, we investigated whether the relationship between these neural mechanisms could help explain why item-specific priming generates faster responses than category-wide priming. Participants studied pictures of everyday objects, and then performed a difficult picture identification task while we recorded event-related potentials (ERP). The identification task gradually revealed random line segments of previously viewed items (Studied), category exemplars of previously viewed items (Exemplar), and items that were not previously viewed (Unstudied). Studied items were identified sooner than Unstudied items, showing evidence of item-specific priming, and importantly Exemplar items were also identified sooner than Unstudied items, showing evidence of category-wide priming. Early activity showed sustained neural suppression of parietal activity for both types of priming. However, these neural suppression effects may have stemmed from distinct processes because while category-wide neural suppression was correlated with priming behavior, item-specific neural suppression was not. Late activity, examined with response-locked ERPs, showed additional processes related to item-specific priming including neural suppression in occipital areas and parietal activity that was correlated with behavior. Together, we conclude that item-specific and category-wide priming are mediated by separate, parallel neural mechanisms in the context of the current paradigm. Temporal differences in behavior are determined by the timecourses of these distinct processes.     

Levels of visuo-spatial selection: An ERP study of negative priming

Usually, a probe target appearing in a recently ignored distractor location is less efficiently processed. This robust phenomenon is called (visuo-) spatial negative priming (SNP). Among other explanations, concepts of persisting or retrieved spatial inhibition play a major role. Two relevant issues were investigated using event-related brain potentials (ERPs). The first pertains to context sensitivity of inhibition: Is a probe distractor necessary for SNP? The second concerns levels of processing at which spatial inhibition operates: Does SNP affect perception, selection, and/or stimulus classification? A localization task with and without probe distractors was employed while 64-channel EEG was recorded. Obviously, SNP does not require a probe distractor; the distractor-absent SNP effect was larger than the distractor-present SNP effect. Distractor-present SNP had two lateralized ERP effects, N1pc amplitude reduction and N2pc amplitude increase. Smaller N1pc may indeed reflect perceptual decrement, but was inversely related to size of behavioral SNP. By contrast, only strong-SNP participants showed N2pc increase, which points to selection disadvantage due to persisting inhibition of higher-level spatial representations. Distractor-absent SNP had no N1pc/N2pc correlates; instead, reduced amplitude of a broadly distributed P300 component suggests impaired stimulus classification due to episodic retrieval of inappropriate prime information. Overall, SNP seems to emerge from relatively late stages of processing, thus challenging the idea of context-free persisting inhibition of low-level spatial representations. Furthermore, distractor-present and distractor-absent SNP are qualitatively different from each other.     

Personal and impersonal stimuli differentially engage brain networks during moral reasoning

Moral decision making has recently attracted considerable attention as a core feature of all human endeavors. Previous functional magnetic resonance imaging studies about moral judgment have identified brain areas associated with cognitive or emotional engagement. Here, we applied graph theory-based network analysis of event-related potentials during moral decision making to reveal the personal/impersonal distinction in the organization of functional connectivity. Our results indicated that the personal task had more larger long-range connections involved in frontal regions and the right hemisphere, and higher network efficiency of some frontal electrodes such as F2 than the impersonal. These might be related to brain resource reorganization contributing to efficient conflict resolution. These findings provide new insights into neural mechanisms of moral dilemmas.     

Semantic relations differentially impact associative recognition memory: Electrophysiological evidence

Though associative recognition memory is thought to rely primarily on recollection, recent research indicates that familiarity might also make a substantial contribution when to-be-learned items are integrated into a coherent structure by means of an existing semantic relation. It remains unclear how different types of semantic relations, such as categorical (e.g., dancer–singer) and thematic (e.g., dancer–stage) relations might affect associative recognition, however. Using event-related potentials (ERPs), we addressed this question by manipulating the type of semantic link between paired words in an associative recognition memory experiment. An early midfrontal old/new effect, typically linked to familiarity, was observed across the relation types. In contrast, a robust left parietal old/new effect was found in the categorical condition only, suggesting a clear contribution of recollection to associative recognition for this kind of pairs. One interpretation of this pattern is that familiarity was sufficiently diagnostic for associative recognition of thematic relations, which could result from the integrative nature of the thematic relatedness compared to the similarity-based nature of categorical pairs. The present study suggests that the extent to which recollection and familiarity are involved in associative recognition is at least in part determined by the properties of semantic relations between the paired associates.     

Event-Related Potential and Behavioral Measures of Attention in 5-, 7-, and 9-Year-Olds

In 2 experiments, the development of auditory selective attention in children was assessed. The participants, aged 5, 7, and 9 years, responded to target stimuli in the left ear for 1 series (ignoring the standard stimuli) and in the right ear for the other series. In Experiment 1, event-related potentials (ERPs) evoked by the auditory stimuli were recorded from frontal, central, and parietal sites. The 9-year-olds showed a greater processing negativity (Nd) to the attended channel compared with the 5-year-olds. Both 7-and 9-year-olds showed significantly larger amplitudes for the P3 component of ERPs in the attended vs. ignored condition. Behaviorally, the 5-year-olds made fewer hits and more false alarms than did older children, and the 9-year-olds made significantly more false alarms than did the 7-year-olds. The results of Experiment 2 showed that the detriment in the performance of the 9-year-olds was a result of task parameters. The inability of 5-year-olds to attend selectively appears to involve problems with the inhibition of the processing of irrelevant information and with selection of the correct response.