Errors without conflict: implications for performance monitoring theories of anterior cingulate cortex

Recent theories of the neural basis of performance monitoring have emphasized a central role for the anterior cingulate cortex (ACC). Replicating an earlier event-related potential (ERP) study, which showed an error feedback negativity that was modeled as having an ACC generator, we used event-related fMRI to investigate whether the ACC would differentiate between correct and incorrect feedback stimuli in a time estimation task. The design controlled for response conflict and frequency and expectancy effects. Although participants in the current study adjusted their performance following error feedback, we did not observe error feedback-evoked ACC activity. In contrast, we did observe ACC activity while the same subjects performed the Stroop task, in which an area of the ACC activated during both conflict and error trials. These findings are inconsistent with previous dipole models of the error feedback negativity, and suggest the ACC may not be involved in the generation of this ERP component. These results question involvement of the ACC in the detection of errors per se when controlling for conflict.     

Modeling relations between hassles and internalizing and externalizing symptoms in adolescents: a four-year prospective study

This study examined the relations between hassles and internalizing and externalizing symptoms across 4 years in adolescents who varied with regard to their risk for psychopathology. The sample comprised 240 adolescents assessed in 6th, 7th, 8th, and 9th grades regarding their level of peer and academic hassles and internalizing and externalizing symptoms. Structural equation modeling was used to construct latent variables of hassles and internalizing and externalizing syndromes. Results varied by informant about the teens' symptoms. For adolescent report, the stress exposure model fit the data best for internalizing syndromes; that is, higher levels of stressors predicted significantly higher levels of self-reported symptoms 1 year later. For mother report of adolescents' symptoms, the stress generation model fit the data best for both internalizing and externalizing syndromes; that is, higher levels of adolescents' internalizing and externalizing symptoms, as reported by their mothers, significantly predicted higher levels of hassles 1 year later.     

Conflict monitoring and cognitive control

A neglected question regarding cognitive control is how control processes might detect situations calling for their involvement. The authors propose here that the demand for control may be evaluated in part by monitoring for conflicts in information processing. This hypothesis is supported by data concerning the anterior cingulate cortex, a brain area involved in cognitive control, which also appears to respond to the occurrence of conflict. The present article reports two computational modeling studies, serving to articulate the conflict monitoring hypothesis and examine its implications. The first study tests the sufficiency of the hypothesis to account for brain activation data, applying a measure of conflict to existing models of tasks shown to engage the anterior cingulate. The second study implements a feedback loop connecting conflict monitoring to cognitive control, using this to simulate a number of important behavioral phenomena.     

Eating disorder examination questionnaire: norms for young adolescent girls

This paper reports young adolescent female norms for the Eating Disorder Examination Questionnaire (EDE-Q). The standardization sample was comprised of 808 girls aged between 12 and 14 years from three single-sex schools (one private and two state schools). Means, standard deviations and percentile ranks for raw EDE-Q subscale scores are presented. Prevalence figures for key eating disorder behaviors over the previous two weeks were as follows: 4% self-induced vomiting; 1% laxative misuse; 0.4% diuretic misuse; and 8% regular binge eating.     

Assessing inhibitory control: a revised approach to the stop signal task

The stop signal task (stop task) is designed to assess inhibitory control and is a frequently used research tool in clinical disorders such as ADHD and schizophrenia. Previous methods of setting stop signal delay and of assessing inhibitory control are problematic. The current study reports two modifications that improve the task as a measure of inhibitory control. The first modification was to set stop signal delays proportional to go mean reaction time (go MRT) to better account for inter-subject variability in go MRT. Twenty-eight normal children were tested, and all standard, stop task dependent measures were obtained when delays were set by this method. The second modification was to calculate a novel dependent measure called the area of inhibition (AOI) which provides a more complete measure of inhibitory control than the slope of the relative finishing time z-scores (ZRFT-slope). Implications for the assessment of inhibitory control in clinical populations are discussed.     

Overactive action monitoring in obsessive-compulsive disorder: evidence from functional magnetic resonance imaging

The anterior cingulate cortex (ACC) in patients with obsessive-compulsive disorder (OCD) has been found to be hyperactive at rest, during symptom provocation, and after commission of errors in cognitive tasks. This hyperactivity might reflect an abnormality in conflict detection, a hypothesized basic mechanism for the action-monitoring function of the ACC. This hypothesis was tested using functional magnetic resonance imaging, by scanning 11 OCD patients and 13 matched control subjects while they performed a version of the continuous-performance task with four trial types that induced graded levels of response conflict. Although a behavioral index of conflict (i.e., accuracy) was similar for patients and control subjects, the ACC activation was increased in patients during high-conflict trials. The error-related activity in the same brain region was also higher in patients, consistent with previous electrophysiological findings. Both conflict- and error-related activity showed trends for positive correlations with severity of OCD symptoms, but not with anxiety. These findings suggest that as part of an overactive action-monitoring system, the ACC is more directly involved in the pathophysiology of OCD than previously thought.