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.

Six-month-olds reliably discriminate different monkey and human faces whereas 9-month-olds only discriminate different human faces. It is often falsely assumed that perceptual narrowing reflects a permanent change in perceptual abilities. In 3 experiments, ninety-six 12-month-olds' discrimination of unfamiliar monkey faces was examined. Following 20 s of familiarization, and two 5-s visual-paired comparison test trials, 12-month-olds failed to show discrimination. However, following 40 s of familiarization and two 10-s test trials, 12-month-olds showed reliable discrimination of novel monkey faces. A final experiment was performed demonstrating 12-month-olds' discrimination of the monkey face was due to the increased familiarization rather than increased time of visual comparison. Results are discussed in the context of perceptual narrowing, in particular the flexible nature of perceptual narrowing.

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.

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Introduction Day-of-injury (DOI) brain lesion volumes in traumatic brain injury (TBI) patients are rarely used to predict long-term outcomes in the acute setting. The purpose of this study was to investigate the relationship between acute brain injury lesion volume and rehabilitation outcomes in patients with TBI at a Level One Trauma Center. Methods Patients with TBI who were admitted to our rehabilitation unit after the acute care trauma service from February 2009-July 2011 were eligible for the study. Demographic data and outcome variables including cognitive and motor FIM scores, length of stay (LOS) in the rehabilitation unit, and ability to return to home were obtained. DOI quantitative injury lesion volumes and degree of midline shift were obtained from day-of-injury (DOI) brain computed tomography (CT) scans. A multiple step-wise regression model including 13 independent variables was created. This model was used to predict post-rehabilitation outcomes, including FIM scores and ability to return to home. P<0.05 was considered significant. Results 96 patients were enrolled in the study. Mean age was 43±21 years, admission Glasgow Coma Score 8.4±4.8, Injury Severity Score 24.7±9.9, and head Abbreviated Injury Scale score 3.73±0.97. Acute hospital length of stay (LOS) was 12.3±8.9 days and rehabilitation LOS was 15.9±9.3 days. Day-of-injury TBI lesion volumes were inversely associated with cognitive FIM scores at rehabilitation admission (p=0.004) and discharge (p=0.004) and inversely associated with ability to be discharged to home after rehabilitation (p=0.006). Conclusion In a cohort of patients with moderate to severe TBI requiring a rehabilitation unit stay after the acute care hospital stay, DOI brain injury lesion volumes are associated with worse cognitive FIM scores at the time of rehabilitation admission and discharge. Smaller injury volumes were associated with eventual discharge to home. Volumetric neuroimaging in the acute injury phase may improve surgeons’ ultimate outcome predictions in TBI patients. Level of Evidence/Study Type Level V, case series, Prognostic/Epidemiological