Oxazepam alters action monitoring.
BACKGROUND
Oxazepam has been demonstrated to slow reaction times and increase the rate of omission errors in attentional experiments. This suggests that action monitoring might also be impaired.


OBJECTIVE
The present study used the event-related brain potential (ERP) technique to investigate this hypothesis. The P3b component to targets was taken as an indicator of the target evaluation process, and the response-locked error-related negativity (ERN) served as an indicator of action monitoring. We hypothesized that the amplitudes of ERN and P3b would be reduced as an effect of oxazepam.


METHODS
A simple "oddball" reaction time experiment was conducted in a double-blind crossover study of 30 mg oxazepam versus placebo. In order to investigate variations in attentional allocation, separate experimental runs were undertaken with target frequencies of 50% and 80%.


RESULTS
ERN and P3b amplitudes were lower in the 80% target condition than in the 50% condition. Oxazepam did not affect behavioral parameters but was associated with an ERN of lower amplitude than the placebo condition. ERN amplitude variations between target conditions remained unchanged.


CONCLUSIONS
Although the intake of 30 mg oxazepam did not impair behavioral performance, measures of the electrophysiological recordings show that action monitoring processes were altered. We argue that this may be related to the anxiolytic properties of the drug and may constitute an important causal factor for behavioral impairments after the intake of oxazepam.
Johannes
S
S
Department of Neurology, Medical School of Hannover, 30623 Hannover, Germany. johannes.soenke@mh-hannover.de
Wieringa
B M
BM
Nager
W
W
Dengler
R
R
Münte
T F
TF
D000328:Adult; D000704:Analysis of Variance; D014151:Anti-Anxiety Agents / Q000494:pharmacology*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005071:Evoked Potentials / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D008297:Male; D010076:Oxazepam / Q000494:pharmacology*; D011930:Reaction Time / Q000187:drug effects* / Q000502:physiology
D014151:Anti-Anxiety Agents; D010076:Oxazepam