Structural and functional changes of the cingulate gyrus following traumatic brain injury: relation to attention and executive skills.

Impairments of attention and executive functions are common sequelae of traumatic brain injury (TBI). The anterior cingulate is implicated in conflict-related task performance, such as the Stroop, and is susceptible to TBI-related injury due to its frontal location and proximity to the rough surface of the falx cerebri. We investigated the relationship between cingulate cortex volume and performance on tasks of selective attention and cognitive flexibility (single-trial Stroop and Auditory Consonant Trigrams [ACT]). Participants consisted of 12 adults with severe TBI and 18 controls. T1-weighted volumetric MRI data were analyzed using automated cortical reconstruction, segmentation, parcellation, and volume measurement. Cortical volume reductions were prominent bilaterally in frontal, temporal, and inferior parietal regions.Specific regional reduction of the cingulate cortex was observed only for cortical volume of right caudal anterior cingulate(cACC). The TBI group performed significantly worse than control participants on the Stroop and ACT tasks. Findings suggest that atrophy of the right cACC may contribute to reduced performance on executive function tasks, such as the Stroop and ACT, although this is likely but one node of an extensive brain network involved in these cognitive processes.

Temporal stability of the error-related negativity (ERN) and post-error positivity (Pe): the role of number of trials.

The error-related negativity (ERN) and post-error positivity (Pe) components of the event-related potential (ERP) are relatively stable over time. The current study further assessed the temporal reliability of ERN and Pe amplitudes for random samples of 2 to 14 trials per participant and the grand mean over a 2-week retest interval. In a replication of previous results, intraclass and zero-order correlations revealed moderate to good temporal stability for participants' (N=20) grand mean ERN and Pe component amplitudes. Adding trials increased test-retest reliabilities; however, the temporal stability of ERN and Pe amplitudes with 14 or fewer trials were modest at best and considerably lower than that for the grand means. Overall, data support the temporal stability of grand-mean ERN and Pe amplitudes and suggest that more than 14 trials are needed to include in ERN and Pe averages for adequate test-retest reliability.

The relationship between performance monitoring, satisfaction with life, and positive personality traits.

Neural reflections of performance monitoring, including the error-related negativity (ERN) component of the event-related potential (ERP), are modulated by personality and affective constructs. Little is known, however, about the relationship between positive personality traits and neural indices of performance monitoring. We investigated the relationship between measures of positive personality traits, including satisfaction with life, dispositional optimism, and positive affect, and indices of performance monitoring in a sample of 45 neurologically-healthy individuals. Increased satisfaction with life was associated with decreased (i.e., less negative) ERN amplitude. Dispositional optimism and positive affect were not related to ERN amplitude. Results remained consistent when negative affect and measures of positive personality were accounted for using multiple regression. There were no relationships between measures of positive personality and the post-error positivity (Pe) or behavioral indices. Findings are consistent with an affective salience interpretation of the ERN, with errors potentially being less meaningful for individuals with higher satisfaction with life.

Empathy and error processing.

Recent research suggests a relationship between empathy and error processing. Error processing is an evaluative control function that can be measured using post-error response time slowing and the error-related negativity (ERN) and post-error positivity (Pe) components of the event-related potential (ERP). Thirty healthy participants completed two measures of empathy, the Interpersonal Reactivity Index (IRI) and the Empathy Quotient (EQ), and a modified Stroop task. Post-error slowing was associated with increased empathic personal distress on the IRI. ERN amplitude was related to overall empathy score on the EQ and the fantasy subscale of the IRI. The Pe and measures of empathy were not related. Results remained consistent when negative affect was controlled via partial correlation, with an additional relationship between ERN amplitude and empathic concern on the IRI. Findings support a connection between empathy and error processing mechanisms.