Intact error monitoring in combat Veterans with post-traumatic stress disorder

Abstract

The error-related negativity (ERN) is a neuroelectric signature of performance monitoring during speeded response time tasks. Previous studies indicate that individuals with anxiety disorders show ERN enhancements that correlate with the degree of clinical symptomology. Less is known about the error monitoring system in post-traumatic stress disorder (PTSD). PTSD is characterized by impairments in the regulation of fear and other emotional responses, as well as deficits in maintaining cognitive control. Here, combat Veterans with PTSD were compared to control Veterans in two different versions of the flanker task (n=13 or 14 per group). Replicating and extending previous findings, PTSD patients showed an intact ERN in both experiments. In addition, task performance and error compensation behavior were intact. Finally, ERN amplitude showed no relationship with self-reported PTSD, depression, or post-concussive symptoms. These results suggest that error monitoring represents a relative strength in PTSD that can dissociate from cognitive control functions that are impaired, such as response inhibition and sustained attention. A healthy awareness of errors in external actions could be leveraged to improve interoceptive awareness of emotional state. The results could have positive implications for PTSD treatments that rely on self-monitoring abilities, such as neurofeedback and mindfulness training.

Keywords: Anterior cingulate cortex; Anxiety; Cognitive control; Error-related negativity; Mild traumatic brain injury; Performance monitoring; Self-monitoring.

Fig. 1

ERPs are shown at six midline electrodes for Control participants (left) and PTSD participants (right). Response onset is at the vertical bar, and ERPs are shown from 200 ms pre-response to 500 ms post-response (x-axis is time in ms). The baseline interval is −200 to 0 ms pre-response. Scale for the y-axis is −10 μ’V to +15 μ’V in all cases, with negative voltage plotted upwards. The ERN (0–100 ms) is labeled at FCz, and the Pe component (200–400 ms) is labeled at Pz. Top: Grand average ERPs in Experiment 1. Bottom: Grand average ERPs in Experiment 2.

Fig. 2

ERP overlay of controls (blue lines) vs. PTSD participants (green lines) for Error trials (left) and Correct trials (right) at electrode FCz. Response onset is at the vertical bar, and ERPs extend from 200 ms pre-response to 900 ms post-response, with a −200 to 0 ms baseline. Scale for the y-axis is −10 μ’V to +15 μ’V, with negative plotted up. Top: Experiment 1. Bottom: Experiment 2.

Fig. 3

Voltage maps displaying the scalp topography for the Error-Correct difference waves for the ERN (measured as mean amplitude between 0–100 ms) and the Pe (mean amplitude between 200–400 ms) in Controls and PTSD patients. Left lateral electrodes are shown on the left side of each map, and right is on the right. Top: Topographic maps in Experiment 1. Scale bar extends from −5.5 μ’V to +3.5 μ’V. Bottom: Topographic maps in Experiment 2. Scale bar extends from −8 μ’V to +8 μ’V.