Event-related potentials and the decision to shoot: The role of threat perception and cognitive control

Participants played a videogame in which they were required to make speeded shoot/don’t-shoot decisions in response to armed and unarmed targets, half of whom were Black, half of whom were White. Event-related brain potentials (ERPs), recorded during the game, assessed attentional processes related to target race and object type. Early ERP components (i.e., the P200 and N200) differentiated between Black and White targets, as well as between armed and unarmed targets. Explicitly measured cultural stereotypes predicted both this racial ERP differentiation and racial bias in the game. Most importantly, the degree of racial differentiation in the early ERP components predicted behavioral bias in the videogame and mediated the relationship between cultural stereotypes and bias.     

The organization of words and environmental sounds in the second year: Behavioral and electrophysiological evidence

The majority of research examining early auditory‐semantic processing and organization is based on studies of meaningful relations between words and referents. However, a thorough investigation into the fundamental relation between acoustic signals and meaning requires an understanding of how meaning is associated with both lexical and non‐lexical sounds. Indeed, it is unknown how meaningful auditory information that is not lexical (e.g., environmental sounds) is processed and organized in the young brain. To capture the structure of semantic organization for words and environmental sounds, we record event‐related potentials as 20‐month‐olds view images of common nouns (e.g., dog) while hearing words or environmental sounds that match the picture (e.g., “dog” or barking), that are within‐category violations (e.g., “cat” or meowing), or that are between‐category violations (e.g., “pen” or scribbling). Results show both words and environmental sounds exhibit larger negative amplitudes to between‐category violations relative to matches. Unlike words, which show a greater negative response early and consistently to within‐category violations, such an effect for environmental sounds occurs late in semantic processing. Thus, as in adults, the young brain represents semantic relations between words and between environmental sounds, though it more readily differentiates semantically similar words compared to environmental sounds.     

认知行为治疗的生物学机制

现阶段认知行为治疗的生物学机制尚不明确。本文将从脑功能、神经电生理、神经内分泌与免疫以及遗传与表观遗传这四个方面对认知行为治疗的生物学机制进行讨论, 综合心理、生理和遗传三方面的结果, 从微观、中间和宏观多层面提出了认知行为治疗生物学机制的整合模型。并进一步对目前研究的局限性进行了讨论, 为未来探究认知行为治疗的生物学机制提供了新的方向。     

Electrophysiological response during source memory decisions in older and younger adults

We recorded event-related potentials (ERPs) as individuals made source monitoring decisions in a paradigm in which the influence of item familiarity and goal relevance could be separately evaluated. Younger and older adults read a list of words and subsequently distinguished these words from foils in a running recognition test in which some foils were repeated after a lag of 6 items, creating familiar lures. Behaviorally, older and younger adults performed equally well in the recognition of study words and the rejection of singly presented foils. However, older adults were more likely to respond to the familiar lures as though they had come from the study list, thus producing the expected group difference in source-monitoring error. For younger adults the ERPs elicited by the targeted study words were maximal at posterior sites and significantly greater than those elicited by either familiar lures or foils. Older adults generated far less differentiated ERP waveforms but with a markedly greater amplitude at frontal sites. We interpret this frontal maximum in the context of poorer source monitoring as suggesting that older adults are more dependent on controlled processes to make discriminations that seem to occur much earlier and more automatically for younger adults.     

The effect of intentional expectancy on mental processing: a chronopsychophysiological investigation

Expected events are processed faster than unexpected ones. Previously, we have reported evidence that passive expectancies determined by the preceding event sequence mainly affected the duration of motoric processes. Here we examined the effects of instructed, intentional expectancies in a two-choice reaction time (RT) task. As predicted, RTs were shorter for expected than unexpected events. Onset of the lateralized readiness potential as an index of selective response activation, and the latency of the P300 component of the event-related potential, reflecting the duration of perceptual processing, indicated that intentional expectancy affected the time demands for central processing but did not influence the duration of early perceptual or motoric processes. Together the present and our previous results provide evidence that different kinds of expectancy can be distinguished by their locus of action within the information processing system.     

Who Do You Love, Your Mother or Your Horse? An Event-Related Brain Potential Analysis of Tone Processing in Mandarin Chinese

In Mandarin Chinese, word meaning is partially determined by lexical tone (Wang, 1973). Previous studies suggest that lexical tone is processed as linguistic information and not as pure tonal information (Gandour, 1998; Van Lanker & Fromkin, 1973). The current study explored the online processing of lexical tones. Event-related potentials were obtained from 25 Mandarin speakers while they listened to normal and anomalous sentences containing one of three types of semantic anomalies created by manipulating the tone, the syllable, or both tone and syllable (double-anomaly) of sentence-final words. We hypothesized N400 effects elicited by all three types of anomalies and the largest by the double-anomaly. As expected, all three elicited N400 effects starting approximately 150 ms poststimulus and continuing until 1000 ms in some areas. Surprisingly, onset of the double-anomaly effect was approximately 50 ms later than the rest. Delayed detection of errors in this condition may be responsible for the apparent delay. Slight differences between syllable and tone conditions may be due to the relative timing of these acoustic cues.     

Prosodic boundaries, comma rules, and brain responses: the closure positive shift in ERPs as a universal marker for prosodic phrasing in listeners and readers

Just as the false comma in this sentence, shows punctuation can influence sentence processing considerably. Pauses and other prosodic cues in spoken language serve the same function of structuring the sentence in smaller phrases. However, surprisingly little effort has been spent on the question as to whether both phenomena rest on the same mechanism and whether they are equally efficient in guiding parsing decisions. In a recent study, we showed that auditory speech boundaries evoke a specific positive shift in the listeners' event-related brain potentials (ERPs) that indicates the sentence segmentation and resulting changes in the understanding of the utterance (Steinhauer et al., 1999a). Here, we present three ERP reading experiments demonstrating that the human brain processes commas in a similar manner and that comma perception depends crucially on the reader's individual punctuation habits. Main results of the study are: (1) Commas can determine initial parsing as efficiently as speech boundaries because they trigger the same prosodic phrasing covertly, although phonological representations seem to be activated to a lesser extent. (2) Independent of the input modality, this phrasing is reflected online by the same ERP component, namely the Closure Positive Shift (CPS). (3) Both behavioral and ERP data suggest that comma processing varies with the readers' idiosyncratic punctuation habits. (4) A combined auditory and visual ERP experiment shows that the CPS is also elicited both by delexicalized prosody and while subjects replicate prosodic boundaries during silent reading. (5) A comma-induced reversed garden path turned out to be much more difficult than the classical garden path. Implications for psycholinguistic models and future ERP research are discussed.     

操作表征在被试操作效应中的调节作用：ERPs研究

本研究考察操作表征(operational representation)在被试操作效应中的调节作用。选取结构性/功能性操作表征短语各160个,分析再认判断中的脑电差异。结果表明,动作编码比语词编码诱发更显著的P1、N2pb和N400;在500~700ms时间窗,相比于语词编码,对结构性和功能性操作表征短语进行动作编码均可显著诱发了中央区更负的平均波幅;在700~900ms时间窗,仅对于结构性操作表征短语,动作编码比语词编码诱发了前额叶更正的平均波幅。研究为动作编码的语义反馈加工机制提供了数据支撑,也为动作信息再激活与动作表征观点的整合提供解释方向。     

Compensatory processing during rule-based category learning in older adults

Healthy older adults typically perform worse than younger adults at rule-based category learning, but better than patients with Alzheimer’s or Parkinson’s disease. To further investigate aging’s effect on rule-based category learning, we monitored event-related potentials (ERPs) while younger and neuropsychologically typical older adults performed a visual category-learning task with a rule-based category structure and trial-by-trial feedback. Using these procedures, we previously identified ERPs sensitive to categorization strategy and accuracy in young participants. In addition, previous studies have demonstrated the importance of neural processing in the prefrontal cortex and the medial temporal lobe for this task. In this study, older adults showed lower accuracy and longer response times than younger adults, but there were two distinct subgroups of older adults. One subgroup showed near-chance performance throughout the procedure, never categorizing accurately. The other subgroup reached asymptotic accuracy that was equivalent to that in younger adults, although they categorized more slowly. These two subgroups were further distinguished via ERPs. Consistent with the compensation theory of cognitive aging, older adults who successfully learned showed larger frontal ERPs when compared with younger adults. Recruitment of prefrontal resources may have improved performance while slowing response times. Additionally, correlations of feedback-locked P300 amplitudes with category-learning accuracy differentiated successful younger and older adults. Overall, the results suggest that the ability to adapt one’s behavior in response to feedback during learning varies across older individuals, and that the failure of some to adapt their behavior may reflect inadequate engagement of prefrontal cortex.     

情绪性注意瞬脱的认知机制:来自行为与ERP的证据

从过度投入理论与激活反弹理论对瓶颈理论的质疑出发,采用ERP技术检验了情绪性注意瞬脱的加工过程及其神经机制。行为结果显示,以恐惧面孔为T1,中性场景图片为T2,则恐惧面孔T1相对中性面孔T1显著降低了中性T2的识别正确率,进而诱发了情绪性注意瞬脱。ERP结果进一步显示,相较于中性面孔T1,恐惧面孔T1诱发的情绪加工影响了代表中枢加工资源的两阶段P3波幅,使得其始终高于代表标准注意瞬脱的中性面孔T1条件和代表非注意瞬脱的单任务基线条件。以上结果证明,情绪性注意瞬脱形成自情绪性T1加工所诱发的中枢资源过度投入,而非源自中枢资源瓶颈。