Post-error Adjustments Research Articles

A neurophysiological study of the detrimental effects of alprazolam on human action monitoring

In order to adapt their behavior to different unexpected situations, humans need to be able to monitor their performance and detect and correct errors. Benzodiazepines have long been shown to impair performance in humans, but the performance-related neurophysiological processes targeted by these drugs remain largely unknown. In the present article, we assessed the impact of alprazolam administration on relevant aspects of action monitoring, i.e., the monitoring of response conflict and the detection and correction of errors by means of neurophysiological measures. Multichannel event-related brain potentials (ERPs) were recorded to assess the impact of the benzodiazepine alprazolam (0.25 mg and 1.00 mg) on action monitoring and motor preparation in a group of twelve healthy male volunteers who participated in a double-blind cross-over placebo-controlled clinical trial involving a letter flanker task. Error detection was evaluated using the error-related negativity (ERN); response conflict on correct trials was measured by means of the N2 amplitude difference between congruent and incongruent trials; motor preparation was assessed by means of the lateralized readiness potentials (LRPs); and post-error adjustments were assessed by measuring post-error slowing in reaction time. Alprazolam significantly reduced the amplitude of the ERN and the number of corrective responses and increased reaction time and LRP latencies. The drug had no effect on amplitude differences in the N2 component between congruent and incongruent trials or on post-error slowing. Thus, alprazolam was shown to affect brain correlates of error detection (ERN) and motor preparation (LRPs), while it did not disturb conflict monitoring on correct trials (N2) or post-error adjustments of behavior.

Resting anterior cingulate activity and abnormal responses to errors in subjects with elevated depressive symptoms: a 128-channel EEG study.

Depression has been associated with dysfunctional executive functions and abnormal activity within the anterior cingulate cortex (ACC), a region critically involved in action regulation. Prior research invites the possibility that executive deficits in depression may arise from abnormal responses to negative feedback or errors, but the underlying neural substrates remain unknown. We hypothesized that abnormal reactions to error would be associated with dysfunctional rostral ACC activity, a region previously implicated in error detection and evaluation of the emotional significance of events. To test this hypothesis, subjects with low and high Beck Depression Inventory (BDI) scores performed an Eriksen Flanker task. To assess whether tonic activity within the rostral ACC predicted post-error adjustments, 128-channel resting EEG data were collected before the task and analyzed with low-resolution electromagnetic tomography (LORETA) using a region-of-interest approach. High BDI subjects were uniquely characterized by significantly lower accuracy after incorrect than correct trials. Mirroring the behavioral findings, high BDI subjects had significantly reduced pretask gamma (36.5-44 Hz) current density within the affective (rostral; BA24, BA25, BA32) but not cognitive (dorsal; BA24', BA32') ACC subdivision. For low, but not high, BDI subjects pretask gamma within the affective ACC subdivision predicted post-error adjustments even after controlling for activity within the cognitive ACC subdivision. Abnormal responses to errors may thus arise due to lower activity within regions subserving affective and/or motivational responses to salient cues. Because rostral ACC regions have been implicated in treatment response in depression, our findings provide initial insight into putative mechanisms fostering treatment response.

Neural mechanisms involved in error processing: A comparison of errors made with and without awareness

The ability to detect an error in one's own performance and then to improve ongoing performance based on this error processing is critical for effective behaviour. In our event-related fMRI experiment, we show that explicit awareness of a response inhibition commission error and subsequent post-error behaviour were associated with bilateral prefrontal and parietal brain activation. Activity in the anterior cingulate region, typically associated with error detection, was equivalent for both errors subjects were aware of and those they were not aware of making. While anterior cingulate activation has repeatedly been associated with error-related processing, these results suggest that, in isolation, it is not sufficient for conscious awareness of errors or post-error adaptation of response strategies. Instead, it appears, irrespective of awareness, to detect information about stimuli/responses that requires interpretation in other brain regions for strategic implementation of post-error adjustments of behaviour.

Impairment of Error Monitoring Following Sleep Deprivation

To verify if error monitoring, involving detection and remedial actions, is affected by sleep deprivation. Event-related brain potentials (ERPs) and electroencephalogram spectrum during performance of Flanker task were obtained in a within-subject, counter-balanced, repeated-measures design. Sleep deprivation and data collection were conducted in a laboratory setting. Sixteen young healthy adults (7 women, 18-23 years old) Performance and electroencephalogram data were collected after normal sleep and sleep deprivation. Compared to normal sleep, 1 night of sleep deprivation resulted in slower and more varied reaction times, more response errors and omissions, and impaired posterror adjustments to response accuracy. Concomitantly, 2 error-related ERPs, error-related negativity and Pe, showed reduced amplitude measurements after sleep deprivation. Conversely, conflict monitoring as expressed behaviorally and by the N2 component of the ERP was not attenuated by sleep deprivation. Ten of the sixteen participants maintained similar accuracy levels under both sleep conditions, although they still showed reduced error-related negativity and error positivity amplitude measurements and impaired error remedial actions for accuracy. Electroencephalogram spectral activity at beta and theta frequency bands was related to response correctness on subsequent trials but not related to that of preceding trials under both sleep conditions. One night of sleep deprivation impaired both the error detection and error remedial actions and highlighted the inability to avoid making errors again after erroneous responses were already made. The results showed that a vicious cycle occurred between performance deterioration and impairment of error-remedial mechanisms that inevitably led to making more successive errors.

Noradrenergic Stimulation Enhances Human Action Monitoring

Noradrenergic neurotransmission has been associated with the modulation of higher cognitive functions mediated by the prefrontal cortex. In the present study, the impact of noradrenergic stimulation on the human action-monitoring system, as indexed by event-related brain potentials, was examined. After the administration of a placebo or the selective alpha2-adrenoceptor antagonist yohimbine, which stimulates firing in the locus ceruleus and noradrenaline release, electroencephalograpic recordings were obtained from healthy volunteers performing a letter flanker task. Yohimbine led to an increase in the amplitude of the error-related negativity in conjunction with a significant reduction of action errors. Reaction times were unchanged, and the drug did not modify the N2 in congruent versus incongruent trials, a measure of preresponse conflict, or posterror adjustments as measured by posterror slowing of reaction time. The present findings suggest that the locus ceruleus-noradrenaline system exerts a rather specific effect on human action monitoring.

ERP components on reaction errors and their functional significance: a tutorial

Some years ago we described a negative (Ne) and a later positive (Pe) deflection in the event-related brain potentials (ERPs) of incorrect choice reactions [Falkenstein, M., Hohnsbein, J., Hoormann, J., Blanke, L., 1990. In: Brunia, C.H.M., Gaillard, A.W.K., Kok, A. (Eds.), Psychophysiological Brain Research. Tilburg Univesity Press, Tilburg, pp. 192–195. Falkenstein, M., Hohnsbein, J., Hoormann, J., 1991. Electroencephalography and Clinical Neurophysiology, 78, 447–455]. Originally we assumed the Ne to represent a correlate of error detection in the sense of a mismatch signal when representations of the actual response and the required response are compared. This hypothesis was supported by the results of a variety of experiments from our own laboratory and that of Coles [Gehring, W.J., Goss, B., Coles, M.G.H., Meyer, D.E., Donchin, E., 1993. Psychological Science 4, 385–390. Bernstein, P.S., Scheffers, M.K., Coles, M.G.H., 1995. Journal of Experimental Psychology: Human Perception and Performance 21, 1312–1322. Scheffers, M.K., Coles, M.G.H., Bernstein, P., Gehring, W.J., Donchin, E., 1996. Psychophysiology 33, 42–54]. However, new data from our laboratory and that of Vidal et al. [Vidal, F., Hasbroucq, T., Bonnet, M., 1999. Biological Psychology, 2000] revealed a small negativity similar to the Ne also after correct responses. Since the above mentioned comparison process is also required after correct responses it is conceivable that the Ne reflects this comparison process itself rather than its outcome. As to the Pe, our results suggest that this is a further error-specific component, which is independent of the Ne, and hence associated with a later aspect of error processing or post-error processing. Our new results with different age groups argue against the hypotheses that the Pe reflects conscious error processing or the post-error adjustment of response strategies. Further research is necessary to specify the functional significance of the Pe.

Autocorrelation of choice-reaction times

A choice-reaction (CR) task requires that the subject estimate, raking the warning signal or his response on the preceding trial as a reference point, the time when the reaction stimulus is due, so that he can begin deciding on his response at an appropriate time. This paper presents a model for the reproduction of temporal intervals, with particular emphasis on the sequential statistics of a series of such reproductions. When this model is concatenated with the sequential probability ratio test model for 2CRT, it provides a quantitative account of the pattern of autocorrelation found in a series of RTs. There is no corresponding autocorrelation in the incidence of errors, however, because after an error the subject systematically adjusts the epoch at which he begins sampling as a precaution against a further error. These post-error adjustments can readily be incorporated into the model. The ideas presented enable several different CR phenomena to be related, and they have implications for the relation between speed and accuracy, for the form of empirical distributions of RTs, and for the effects of temporal uncertainty.