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1.
Swick D  Jovanovic J 《Neuropsychologia》2002,40(8):1240-1253
Neuroimaging studies have implicated the anterior cingulate cortex (ACC) in many aspects of attention and cognition. Major theories of ACC function have proposed a role in conflict monitoring, executive control, response selection, and general arousal. Although the ACC is often treated as a unitary structure, extensive evidence suggests it exhibits anatomical and functional specificity. ACC activity during the Stroop color word interference task has been of particular interest. The purpose of the present study was to determine whether two different ACC subregions are necessary for intact color naming performance in the Stroop task. One experiment utilized blocked trial and mixed trial designs to emulate neuroimaging studies and to compare interference and facilitation effects, respectively. A third variant manipulated the probabilities of congruent and incongruent trials to alter levels of interference and cognitive control, or engagement of strategic processes, on a block by block basis. Two patients with focal lesions in either right mid-caudal (patient D.L.) or left rostral to mid-dorsal ACC (patient R.N.) exhibited distinctive performance profiles in these three versions of the Stroop task, providing further support for topographic specificity of function within the human ACC. Contrary to predictions from some neuroimaging experiments, damage to right mid-caudal ACC was associated with normal levels of interference and accurate performance on incongruent trials. Instead, D.L. showed reduced levels of facilitation relative to controls. Further, interference was not modulated by the probability manipulation in D.L., suggesting equivalently high levels of cognitive control in both conditions. Conversely, damage to left mid-dorsal ACC resulted in consistently lower accuracy on incongruent trials, indicating deficits in maintaining task set and inhibiting the automatic response. These results can help to constrain interpretations of ACC activations in functional imaging experiments of the Stroop task.  相似文献   

2.
Previous studies have shown that depressed individuals have difficulty directing attention away from negative distractors, a phenomenon known as affective interference. However, findings are mixed regarding the neural mechanisms and network dynamics of affective interference. The present study addressed these issues by comparing neural activation during emotion-word and color-word Stroop tasks in participants with varying levels of (primarily subclinical) depression. Depressive symptoms predicted increased activation to negative distractors in areas of dorsal anterior cingulate cortex (dACC) and posterior cingulate cortex (PCC), regions implicated in cognitive control and internally directed attention, respectively. Increased dACC activity was also observed in the group-average response to incongruent distractors, suggesting that dACC activity during affective interference is related to overtaxed cognitive control. In contrast, regions of PCC were deactivated across the group in response to incongruent distractors, suggesting that PCC activity during affective interference represents task-independent processing. A psychophysiological interaction emerged in which higher depression predicted more positively correlated activity between dACC and PCC during affective interference, i.e. greater connectivity between cognitive control and internal-attention systems. These findings suggest that, when individuals high in depression are confronted by negative material, increased attention to internal thoughts and difficulty shifting resources to the external world interfere with goal-directed behavior.  相似文献   

3.
Goal-directed behavior requires cognitive control to regulate the occurrence of conflict. The dorsal anterior cingulate cortex (dACC) has been suggested in detecting response conflict during various conflict tasks. Recent findings, however, have indicated not only that two distinct subregions of dACC are involved in conflict processing but also that the conflict occurs at both perceptual and response levels. In this study, we sought to examine whether perceptual and response conflicts are functionally dissociated in dACC. Thirteen healthy subjects performed a version of the Stroop task during functional magnetic resonance imaging (fMRI) scanning. We identified a functional dissociation of the caudal dACC (cdACC) and the rostral dACC (rdACC) in their responses to different sources of conflict. The cdACC was selectively engaged in perceptual conflict whereas the rdACC was more active in response conflict. Further, the dorsolateral prefrontal cortex (DLPFC) was coactivated not with cdACC but with rdACC. We suggest that cdACC plays an important role in regulative processing of perceptual conflict whereas rdACC is involved in detecting response conflict.  相似文献   

4.
Cognitive control theory suggests conflict effects are reduced following high- relative to low-conflict trials. Such reactive adjustments in control, frequently termed “conflict adaptation effects,” indicate a dynamic interplay between regulative and evaluative components of cognitive control necessary for adaptable goal-directed behavior. The current study examined conflict adaptation effects while 36 neurologically-normal participants performed a single-trial color-naming Stroop task. Trials preceded by incongruent (high conflict) and congruent (low conflict) trials were compared for behavioral (response time [RT] and error rate) and electrophysiological (N450 and conflict SP components of the event-related potential [ERP]) concomitants of cognitive control. A conflict adaptation effect was present for RTs that could not be accounted for by associative or negative priming. ERPs revealed a parietal conflict slow potential (conflict SP) that differentiated incongruent from congruent trials and monotonically differentiated current trial congruency on the basis of previous-trial context (i.e., showed conflict adaptation); the fronto-medial N450 was sensitive to current trial congruency but not to previous-trial context. Direct comparison of normalized conflict SP and N450 amplitudes showed the conflict SP was sensitive to the effects of previous-trial context, while the N450 was so to a lesser extent and in a different pattern. Findings provide clarification on the neural time course of conflict adaptation and raise further questions regarding the relative roles of the parietal conflict SP and fronto-medial N450 in conflict detection and processing.  相似文献   

5.
OBJECTIVE: People with schizophrenia have exhibited reduced functional activity in the anterior cingulate cortex during the performance of many types of cognitive tasks and during the commission of errors. According to conflict theory, the anterior cingulate cortex is involved in the monitoring of response conflict, acting as a signal for a need for greater cognitive control. This study examined whether impaired conflict monitoring in people with schizophrenia could underlie reduced anterior cingulate activity during both correct task performance and error-related activity. METHOD: Functional activity in the anterior cingulate of 13 schizophrenia patients and 13 healthy comparison subjects was investigated by using event-related fMRI and a Stroop task that allowed simultaneous examination of activity during both conflict (incongruent trials) and error (commission of error trials). RESULTS: In the presence of comparable reaction time measures for conflict as well as comparable error rates, the schizophrenia subjects showed both decreased conflict- and error-related activity in the same region of the anterior cingulate cortex. Moreover, those with schizophrenia did not exhibit significant post-conflict or post-error behavioral adjustments. CONCLUSIONS: Concurrently reduced conflict- and error-related activity in the anterior cingulate cortex along with reduced trial-to-trial adjustments in performance has not previously been reported in schizophrenia. The current results suggest that impaired conflict monitoring by the anterior cingulate cortex might play an important role in contributing to cognitive control deficits in patients with schizophrenia.  相似文献   

6.
One fundamental function of the prefrontal cortex (PFC) is to guide context-appropriate behaviour in situations of response conflict. Haddon and Killcross recently developed a task in rats which mimics some aspects of response conflict seen in human cognitive paradigms such as the Stroop task. Using this paradigm they demonstrated that large PFC lesions including the prelimbic (PL), infralimbic (IL) and anterior cingulate cortices (ACC) selectively impaired performance on incongruent trials which required the use of task-setting contextual cues to control responding in the face of ambiguous response information. The current experiment was conducted to determine whether specific PFC regions were responsible for the deficit in incongruent performance. Rats were trained on two instrumental biconditional discriminations, one auditory and one visual, in two different contexts. Following acquisition, rats were implanted with guide cannulae aimed at the PL or the IL cortices of the rat prefrontal cortex. Following retraining, rats received microinfusions of the GABA(A) agonist muscimol or artificial cerebrospinal fluid (aCSF) into either the PL or the IL prior to presentations of novel congruent and incongruent audiovisual compounds of the training stimuli in extinction. Results showed that temporary inactivation of the PL cortex led to a selective deficit on incongruent compound trials, but left congruent, and hence biconditional task performance intact. By contrast, IL inactivation had no effect on the accuracy of responding during either congruent or incongruent trials. These results suggest that the PL cortex is necessary for the use of task-setting contextual cues to control responding to conflicting information.  相似文献   

7.
Alcohol-dependence is associated with cognitive and biological alterations, and also with interpersonal impairments. Although overwhelming in clinical settings and involved in relapse, these social impairments have received little attention from researchers. Particularly, brain alterations related to social exclusion have not been explored in alcohol-dependence. Our primary purpose was to determine the neural correlates of social exclusion feelings in this population. In all, 44 participants (22 abstinent alcohol-dependent patients and 22 paired controls) played a virtual game ('cyberball') during fMRI recording. They were first included by other players, then excluded, and finally re-included. Brain areas involved in social exclusion were identified and the functional connectivity between these areas was explored using psycho-physiological interactions (PPI). Results showed that while both groups presented dorsal anterior cingulate cortex (dACC) activations during social exclusion, alcohol-dependent participants exhibited increased insula and reduced frontal activations (in ventrolateral prefrontal cortex) as compared with controls. Alcohol-dependence was also associated with persistent dACC and parahippocampal gyrus activations in re-inclusion. PPI analyses showed reduced frontocingulate connectivity during social exclusion in alcohol-dependence. Alcohol-dependence is thus linked with increased activation in areas eliciting social exclusion feelings (dACC-insula), and with impaired ability to inhibit these feelings (indexed by reduced frontal activations). Altered frontal regulation thus appears implied in the interpersonal alterations observed in alcohol-dependence, which seem reinforced by impaired frontocingulate connectivity. This first exploration of the neural correlates of interpersonal problems in alcohol-dependence could initiate the development of a social neuroscience of addictive states.  相似文献   

8.
Successful information processing requires the focusing of attention on a certain stimulus property and the simultaneous suppression of irrelevant information. The Stroop task is a useful paradigm to study such attentional top‐down control in the presence of interference. Here, we investigated the neural correlates of an auditory Stroop task using fMRI. Subjects focused either on tone pitch (relatively high or low; phonetic task) or on the meaning of a spoken word (high/low/good; semantic task), while ignoring the other stimulus feature. We differentiated between task‐related (phonetic incongruent vs. semantic incongruent) and sensory‐level interference (phonetic incongruent vs. phonetic congruent). Task‐related interference activated similar regions as in visual Stroop tasks, including the anterior cingulate cortex (ACC) and the presupplementary motor‐area (pre‐SMA). More specifically, we observed that the very caudal/posterior part of the ACC was activated and not the dorsal/anterior region. Because identical stimuli but different task demands are compared in this contrast, it reflects conflict at a relatively high processing level. A more conventional contrast between incongruent and congruent phonetic trials was associated with a different cluster in the pre‐SMA/ACC which was observed in a large number of previous studies. Finally, functional connectivity analysis revealed that activity within the regions activated in the phonetic incongruent vs. semantic incongruent contrast was more strongly interrelated during semantically vs. phonetically incongruent trials. Taken together, we found (besides activation of regions well‐known from visual Stroop tasks) activation of the very caudal and posterior part of the ACC due to task‐related interference in an auditory Stroop task. Hum Brain Mapp, 2009. © 2009 Wiley‐Liss, Inc.  相似文献   

9.
Cognitive control enables goal-oriented adaptation to a fast-changing environment and has a protracted development spanning into young adulthood. The neurocognitive processes underlying this development are poorly understood. In a cross-sectional sample of participants 8–19 years old (n = 108), we used blind source separation of EEG data recorded in a Flanker task to derive electrophysiological measures of attention and conflict processing, including a N2-like frontal negative component and a P3-like parietal positive component. Outside the recording session, we examined multiple behavioral measures of interference control derived from the Flanker, Stroop, and Anti-saccade tasks. We found a positive association between age and P3 amplitude, but no relationship between age and N2 amplitude. A stronger N2 was age-independently related to better performance on Stroop and Anti-saccade measures of interference control. A Gratton effect was found on the Flanker task, with slower reaction times on current congruent and better accuracy on current incongruent trials when preceded by incongruent as opposed to congruent trials. The Gratton effect on accuracy was positively associated with age. Together, the findings suggest a multifaceted developmental pattern of the neurocognitive processes involved in conflict processing across adolescence, with a more protracted development of the P3 compared to the N2.  相似文献   

10.
The purpose of this study was to investigate the cognitive control process of conflict adaptation and the recruitment of cognitive control across sequential trials-termed higher-order trial effects-using the N2 and P3 components of the scalp-recorded event-related potential (ERP). High-density ERPs were obtained from 181 healthy individuals (93 female, 88 male) during a modified Eriksen flanker task. Behavioral measures (i.e., error rates, reaction times [RTs]) and N2 and P3 amplitudes showed reliable conflict adaptation (i.e., previous-trial congruencies influenced current-trial measures). Higher-order trial effects were quantified across multiple sequential presentations of congruent or incongruent trials (e.g., four consecutive incongruent trials). For higher-order trial effects, P3 amplitudes and RTs reliably decreased across both congruent and incongruent trials. Consistent with the conflict monitoring theory, N2 amplitudes decreased across incongruent trials and increased across congruent trials. N2 amplitudes were positively correlated with incongruent-trial RTs; no significant correlations were found for P3 amplitudes and RTs. Effects remained when stimulus-response repetitions were removed. Results indicate that RTs and ERP measures are sensitive to modulations of cognitive control associated with conflict across multiple congruent and incongruent trials. Implications for the conflict monitoring theory of cognitive control are discussed.  相似文献   

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