Is conflict monitoring supramodal? Spatiotemporal dynamics of cognitive control processes in an auditory Stroop task

The electrophysiological correlates of conflict processing and cognitive control have been well characterized for the visual modality in paradigms such as the Stroop task. Much less is known about corresponding processes in the auditory modality. Here, electroencephalographic recordings of brain activity were measured during an auditory Stroop task, using three different forms of behavioral response (overt verbal, covert verbal, and manual), that closely paralleled our previous visual Stroop study. As was expected, behavioral responses were slower and less accurate for incongruent than for congruent trials. Neurally, incongruent trials showed an enhanced fronto-central negative polarity wave (N_inc), similar to the N450 in visual Stroop tasks, with similar variations as a function of behavioral response mode, but peaking ~150 ms earlier, followed by an enhanced positive posterior wave. In addition, sequential behavioral and neural effects were observed that supported the conflict-monitoring and cognitive adjustment hypothesis. Thus, while some aspects of the conflict detection processes, such as timing, may be modality dependent, the general mechanisms would appear to be supramodal.     

色-词Stroop任务中的冲突类型述评

在认知控制领域中, 色-词Stroop任务常被用于研究冲突加工的内在机制。本文首先简述色-词Stroop任务中的刺激冲突和反应冲突及研究这两类冲突常用的实验范式。然后介绍这两类冲突的神经动力学特征：事件相关电位研究显示, N450的波幅调整反映了大脑对冲突的监测, 持续电位(sustained potential, SP)的波幅调整反映了大脑对反应冲突的解决; 核磁共振成像研究显示, 前扣带回、背外侧前额叶分别在反应冲突的监测、认知控制的执行上扮演着重要的角色。文章最后针对目前研究范式存在的问题提出了改进方法和认知神经研究的新方向。     

听障儿童认知抑制控制的脑电特点

通过认知抑制控制的Stroop范式运用事件相关电位考察听障儿童和对照组儿童在认知抑制控制方面的行为特点以及脑内时程特点。行为结果显示：（1）两类被试在一致条件下认知抑制控制的正确率显著高于不一致条件,反应时显著快于不一致条件,表现出冲突效应;（2）组间结果显示,听障儿童的认知抑制控制正确率显著低于对照组儿童,反应时上差异不显著。脑电结果显示：（1）不一致条件在N450上的负激活显著高于一致条件,听障儿童比对照组儿童诱发了更负的N450波幅;（2）不一致条件在SP上的正激活显著高于一致条件,两类被试在SP上差异不显著。结果提示听障儿童在认知抑制控制过程中的冲突监测功能存在障碍,这是由于冲突监测过程中注意分配能力受损所致。     

音乐训练与抑制控制的关系：来自ERPs的证据

抑制控制是人类非常重要的认知功能之一, 它对个体适应环境具有重要的意义。本研究将抑制控制细分为反应抑制和冲突控制, 采用Go/No-go和Stroop任务从行为和脑电层面, 考察了音乐训练与抑制控制能力的关系及其认知神经机制。结果发现：在行为指标上, 音乐训练组比控制组的Stroop干扰效应更小, 但两组被试在Go/No-go任务表现上没有差异。在脑电指标上, 在Go/No-go任务中音乐训练组的N2差异波和P3差异波波幅(No-go减Go条件)显著大于控制组, 在Stroop任务中音乐训练组的N450差异波波幅(不一致减一致条件)也显著大于控制组, 但两组被试的SP差异波波幅(不一致减一致条件)无显著差异。结果表明：音乐训练组被试在反应抑制任务中可能具有更强的冲突监控和运动抑制能力, 在冲突控制任务中也具有更强的冲突监控能力。本研究从电生理的层面反映了音乐训练与抑制控制能力的提升具有一定的关联。     

海洛因戒治者执行控制功能异常的电生理证据

执行控制障碍是成瘾的核心特征之一,对成瘾者的复发与康复治疗有重要影响。采用事件相关电位(ERP)技术分析海洛因戒治者和健康成年人在经典色-词Stroop任务中执行控制的大脑皮层时程动态变化。行为结果发现,两组被试的反应时均有显著的Stroop干扰效应,但无显著组间差异。ERP结果显示,戒治组不一致条件的平均波幅显著小于对照组;戒治组Stroop任务相关的N2效应和SP消失及N450效应衰减。研究结果表明,海洛因戒治者可能存在早期冲突监控加工障碍和晚期反应冲突解决加工异常。     

What is the nature of increased Stroop interference in schizophrenia?

In comparison to controls, patients with schizophrenia classically display (1) an overall slowing in response times (RTs) and (2) a disproportionate slowing in RTs in the conflict condition of the Stroop color/word interference task. These two effects appear repeatedly in the card version of the Stroop task but were not replicated in a number of studies using a computer item-by-item version of the task. The present study was aimed at understanding the exact nature of the increased interference classically found in the performance of patients with schizophrenia in the card version of the Stroop task. We used a computer trial-by-trial version in which we investigated the effects of two major methodological differences between the two versions: (1) blocked (card version) versus mixed (computer version) presentation of the neutral, congruent and conflict conditions and (2) presence (card version) versus absence (computer version) of distractors in the spatial surrounding of the target. We found an overall slowing in performance and a disproportionate slowing in the conflict condition for patients with schizophrenia but only when the target was surrounded by distractors (in Experiments 2 and 3). The data are discussed in terms of a deficit in selective attention and inhibitory processes in schizophrenia.     

冲突观察能诱发冲突适应

重复启动效应和一致试次所占的比例都会影响冲突适应效应。采用词-色Stroop任务, 本研究在控制了重复启动效应和一致试次的比例之后, 通过三个实验共同探讨反应执行和冲突观察对冲突适应效应的影响。实验一发现当前试次的Stroop干扰效应, 但没有得到冲突适应效应; 在实验二中, 先前试次为四选一的选择反应时任务, 当前试次为词-色Stroop任务, 得到反转的冲突适应效应; 实验三和实验一程序相似, 但在先前试次上不执行反应, 得到了稳定的冲突适应效应。这些结果证明, 冲突观察能够诱发冲突适应机制, 提升当前的操作表现。     

反应与刺激冲突的脑机制差异:来自ERP研究的证据

采用事件相关电位技术(ERP),用侧抑制任务探讨了刺激和反应冲突的脑内时程动态变化。行为数据表明,冲突条件的反应时显著长于无冲突条件,表现出明显的干扰效应;脑电数据表明,在300-450ms内,反应冲突比无冲突诱发了一个更负的ERP成分(N300-450),主要分布于额顶部,偶极子溯源分析发现,这一负成分可能主要源于ACC;而刺激冲突与无冲突相比在350-450ms内,也诱发了一个更负的ERP成分(N350-450),该负成分可能主要源于丘脑附近。这一结果表明,刺激与反应冲突所涉及的大脑机制可能并不相同。     

语言认知加工过程中的早期皮层电位

在一项通过事件相关电位的N400考察双语者的语义表征的实验研究中,我们偶然发现两个早期成分与语言语义和形式认知加工相关。一个是在140毫秒左右达到峰顶的负波(N140),另一个是在190毫秒左右达到峰顶的正波(PJ90)。前者反映了被试对语义的初级分类与评价的神经认知过程;后者则反映了对语言形态的加工过程。     

Early and late mismatch negativity elicited by words and speech-like stimuli in children

In auditory perception the brain's attentional and preattentional mechanisms select certain stimuli for preferential processing and filter out irrelevant input. This study investigated nonattentive auditory processing in children. Event-related potentials (ERPs) provide a means to study neural correlates related to language and speech-sound processing. Mismatch negativity (MMN) is an ERP wave that indicates attention-independent perceptual change detection. In this study cortical ERPs were elicited by complex tones, naturally spoken words, and pseudowords, with each stimulus type containing equal acoustical elements. Tones elicited a bifurcated mismatch negativity (MMN), with early MMN (peaking at 150-200 ms) being more dominant. On the other hand, words elicited a strong late MMN, peaking at about 400-450 ms after stimulus onset. The MMN wave form was significantly weaker for pseudowords than for words. The late MMN wave, especially for word differences, was found to reflect summating MMN generators and memory trace formation on gestalt bases. Results suggest that the auditory processing, even nonattended, is highly associated with the cognitive meaning of the stimuli.     

Distinct conflict resolution deficits related to different facets of Schizophrenia

An important issue in understanding the nature of conflict processing is whether it is a unitary or multidimensional construct. One way to examine this is to study whether people with impaired conflict processing exhibit a general pattern of deficits or whether they exhibit impairments in distinct aspects of conflict processing. One group who might exhibit conflict deficits are people with schizophrenia. Schizophrenia is a heterogeneous disorder, with one way to break down the heterogeneity of schizophrenia is to examine specific symptoms. Previous research has found that specific symptoms of schizophrenia are associated with specific deficits in conflict processing. In particular, disorganization is associated with increased response conflict, alogia is associated with increased retrieval conflict, and anhedonia is associated with increased emotional conflict. Moreover, there is evidence that different types of conflict processing are unassociated with each other. This evidence suggests that conflict processing is a multidimensional construct and that different aspects of schizophrenia are associated with impairments in processing different types of conflict.     

Tracking the timecourse of social perception: the effects of racial cues on event-related brain potentials

Event-related potentials were used to track social perception processes associated with viewing faces of racial ingroup and outgroup members. Activity associated with three distinct processes was detected. First, peaking at approximately 170 ms, faces were distinguished from nonface stimuli. Second, peaking at approximately 250 ms, ingroup members were differentiated from outgroup members, with a larger component suggesting greater attention to ingroup members. This effect may reflect the spontaneous application of a deeper level of processing to ingroup members. Third, peaking at approximately 520 ms, evaluative differentiation of ingroup and outgroup members occurred, with greater ingroup bias displayed by those with higher levels of prejudice on an explicit measure. Together, the results demonstrate the promise of using neural processes to track the presence, timing, and degree of activation of components relevant to social perception, prejudice, and stereotyping.     

Effortful versus automatic emotional processing in schizophrenia: Insights from a face-vignette task

Adaptive emotional responding relies on dual automatic and effortful processing streams. Dual-stream models of schizophrenia (SCZ) posit a selective deficit in neural circuits that govern goal-directed, effortful processes versus reactive, automatic processes. This imbalance suggests that when patients are confronted with competing automatic and effortful emotional response cues, they will exhibit diminished effortful responding and intact, possibly elevated, automatic responding compared to controls. This prediction was evaluated using a modified version of the face-vignette task (FVT). Participants viewed emotional faces (automatic response cue) paired with vignettes (effortful response cue) that signalled a different emotion category and were instructed to discriminate the manifest emotion. Patients made less vignette and more face responses than controls. However, the relationship between group and FVT responding was moderated by IQ and reading comprehension ability. These results replicate and extend previous research and provide tentative support for abnormal conflict resolution between automatic and effortful emotional processing predicted by dual-stream models of SCZ.     

视听跨通道信息的整合与冲突控制

多通道信息交互是指来自某个感觉通道的信息与另一感觉通道的信息相互作用、相互影响的一系列加工过程。主要包括两个方面：一是不同感觉通道的输入如何整合;二是跨通道信息的冲突控制。本文综述了视听跨通道信息整合与冲突控制的行为心理机制和神经机制,探讨了注意对视听信息整合与冲突控制的影响。未来需探究视听跨通道信息加工的脑网络机制,考察特殊群体的跨通道整合和冲突控制以帮助揭示其认知和社会功能障碍的机制。     

The impact of prestimulus EEG frequency on auditory evoked potentials during sleep onset.

Auditory evoked potentials were recorded during wakefulness, Stage 1, and Stage 2 non-REM sleep using a three-tone auditory oddball paradigm. Stage 1 sleep was divided into trials preceded by alpha and those preceded by theta. A negative wave peaking at about 100 ms, N1, displayed a significant decrease in amplitude with the onset of Stage 2 sleep. A later N2 peaked at about 250 ms in the waking state. This changed into a sleep-specific negative wave peaking at 300 ms (N300) at the alpha-theta transition within Stage 1. The P300 displayed a similar shift to become a P450 in Stage 2 sleep. N550 was specific to Stage 2, and was larger in response to rare, rather than frequent stimuli. There was no evidence of any enhancement to relevant rare stimuli compared with irrelevant rare stimuli.     

中英文Stroop干扰效应的脑机制

以中国大学生为被试,采用事件相关电位对比研究中英文Stroop干扰效应的脑内时程动态变化。结果发现：两种文字材料都存在反应时的Stroop干扰效应,汉字的干扰效应明显强于英文;被试在完成不同文字材料的字词颜色命名任务时所诱发的ERP成分存在差异,具体为中文Stroop干扰效应表现为在350—550ms内,不一致条件比一致条件诱发一个更负的ERP成分（N450）,主要分布于额中部电极。英文Stroop干扰效应表现为不一致条件比一致条件在250—450ms内诱发一个更正的ERP成分（P300）,主要分布于左侧额顶叶;在450—550ms内诱发一个更负的ERP成分（N500）,主要分布于中后部。研究结果表明语言类型会影响Stroop干扰效应的脑内时程变化。     

Congruency sequence effect in cross-task context: Evidence for dimension-specific modulation

The congruency sequence effect refers to a reduced congruency effect after incongruent trials relative to congruent trials. This modulation is thought to be, at least in part, due to the control mechanisms resolving conflict. The present study examined the nature of the control mechanisms by having participants perform two different tasks in an alternating way. When participants performed horizontal and vertical Simon tasks in Experiment 1A, and horizontal and vertical spatial Stroop task in Experiment 1B, no congruency sequence effect was obtained between the task congruencies. When the Simon task and spatial Stroop task were performed with different response sets in Experiment 2, no congruency sequence effect was obtained. However, in Experiment 3, in which the participants performed the horizontal Simon and spatial Stroop tasks with an identical response set, a significant congruency sequence effect was obtained between the task congruencies. In Experiment 4, no congruency sequence effect was obtained when participants performed two tasks having different task-irrelevant dimensions with the identical response set. The findings suggest inhibitory processing between the task-irrelevant dimension and response mode after conflict.     

刺激呈现时间对汉字语义加工脑偏侧化的影响

以往关于汉字字词识别脑功能偏侧化的研究发现了左半球优势、右半球优势或者大脑两半球均势三种不同的结果。该研究采用一侧化Stroop范式(刺激分别只呈现于左视野、中央视野或右视野中),通过系统地改变刺激呈现时间以期探讨刺激呈现时间是可以解释这些不一致结果的可能因素之一。结果显示:对于右利手被试,在刺激呈现时间为60 ms时右半球出现了较强的Stroop效应,在刺激呈现200 ms时左右半球的Stroop效应没有表现出差异,在刺激呈现时间较长时左半球表现出较强的Stroop效应。该结果提示,随着刺激呈现时间的延长,语义优势发生了从右半球到左半球的转换。     

Slow and steady: sustained effects of lexico-semantic associations can mediate referential impairments in schizophrenia

The present study investigated the contribution of lexico-semantic associations to impairments in establishing reference in schizophrenia. We examined event-related potentials as schizophrenia patients and healthy, demographically matched controls read five-sentence scenarios. Sentence 4 introduced a noun that referred back to three possible referents introduced in Sentences 1–3. These referents were contextually appropriate, contextually inappropriate but lexico-semantically associated, and contextually inappropriate and lexico-semantically nonassociated. In order to determine whether participants had correctly linked the anaphor to its referent, the final sentence reintroduced each referent, and participants indicated whether the last two sentences referred to the same entity. Results indicated that between 300 and 400 ms, patients, like healthy controls, used discourse context to link the noun with its preceding referent. However, between 400 and 500 ms, neural activity in patients was modulated only by lexico-semantic associations, rather than by discourse context. Moreover, patients were also more likely than controls to incorrectly link the noun with contextually inappropriate but lexico-semantically associated referents. These results suggest that at least some types of referential impairments may be driven by sustained activation of contextually inappropriate lexico-semantic associations.     

Event-related FMRI study of context processing in dorsolateral prefrontal cortex of patients with schizophrenia

Context processing is conceptualized as an executive function involved in voluntary, complex actions such as overcoming automatic responses. The present study tested the hypothesis that context-processing deficits in patients with schizophrenia are associated with a dysfunction of left dorsolateral prefrontal cortex (DLPFC). Using event-related functional magnetic resonance imaging (fMRI), 17 controls and 17 medicated patients performed a version of the AX task in which a learned, automatic response had to be inhibited. In controls, left DLPFC activity increased when preparing to overcome an automatic response, whereas patients with schizophrenia showed no differential activation. In controls, context processing appeared to be associated with the differential representation of cues associated with the need to provide top-down support for overcoming automatic responses. This mechanism appeared to be impaired in patients with schizophrenia.