Effect of benzodiazepine on temporal integration in object perception

Rationale: Though various psychometrical tests indicate that benzodiazepine s affect vigilance, few studies have been conducted to assess the effect of benzodiazepines on attentional processes. Objective: We used a RSVP (Rapid Serial Visual Presentation) procedure to investigate the effect of benzodi azepines on the attentional blink effect. It refers to the difficulty in de tecting a probe following identification of a target within a temporal wind ow of 500 ms. Method: Three experimental groups were tested (placebo, loraz epam and diazepam). Sequences of 15 pictures were centrally displayed for 5 0 ms each. In a dual-task condition, observers were instructed (1) to ident ify the target (the single picture on a blue background) and (2) to detect the presence of a probe. In the single-task condition, subjects were asked to detect the probe. The serial position of the probe relative to the targe t was varied. Results: Performance was equivalent for the three groups in t he single task condition. In the dual-task condition, the attentional blink was increased in magnitude and duration for benzodiazepine-treated subject s, especially diazepam, than fur placebo-treated subjects. A large number o f intrusions (a tendency to report as target the name of a picture precedin g the target) were observed in the benzodiazepine-treated groups. Conclusio n: The results indicate that benzodiazepines impair visual integration in t he temporal domain. This extends previous findings that benzodiazepine impa irs visual integration in the spatial domain. The results also suggest that benzodiazepine increase time to disengage attention from a first to a seco nd target.