Scopolamine and lorazepam exert different patterns of effects in a test battery assessing stages of information processing

Abstract

The effects of a single dose of scopolamine (0.5 mg) SC and of lorazepam (2.5 mg) PO were tested in two independent studies for their effects on performance in a psychometric battery which measured functions related to different stages of information processing. Attention and vigilance were measured by a continuous attention task and a vigilance task, respectively. Working memory and reasoning were evaluated by the rapid information processing and logical reasoning task; memory acquisition and storage were measured by pre- and post-drug immediate and delayed recall using visual material. The following pattern of effects was revealed; both scopolamine and lorazepam impaired performance in attentional and vigilance tasks as well as in the rapid information processing task significantly (P < 0.05) when compared with their own placebo; in the logical reasoning task lorazepam significantly prolonged the time required to solve a problem; scopolamine did not have any effect on this task. Scopolamine impaired performance in the immediate recall but left delayed recall unaffected; lorazepam impaired only delayed recall, immediate recall remaining unaffected. These data suggest that scopolamine at this dose impaired mostly attention and early stages of information processes; lorazepam at the dose tested impaired also the later acquisition and encoding aspects of memory.

Effects of Lorazepam on the Neuromagnetic Mismatch Negativity (MMNm) and Auditory Evoked Field Component N100m

“…An impact of lorazepam on CPT performance has been expected from known effects of lorazepam, as well as from earlier studies (Duka et al, 1995;Fluck et al, 2001;Kathmann et al, 1996;Krystal et al, 1998;Mass et al, 2000;Micallef et al, 2001;Post et al, 1997). The data illustrate that the performance in controlled visual attention was clearly impaired by lorazepam intake.…”

“…Besides that, on the behavioral level an attenuation of attention performance with benzodiazepines is well documented (Duka et al, 1995;Fluck et al, 2001;Krystal et al, 1998;Micallef et al, 2001;Post et al, 1997). However, since attention can be regarded as a process of information and response selection, pure behavioral studies can hardly reveal which levels of information processing are affected by benzodiazepines.…”

Scopolamine slows the orienting of attention in primates to cued visual targets

“…For example, scopolamine, which blocks muscarinic cholinergic transmission, impairs sustained and divided attention by slowing RTs, increasing error rates, and increasing distractibility (Callahan et al 1993;McGaughy et al 1994;Duka et al 1995;Jones and Higgins 1995).…”

Effects of the amnesic drug lorazepam on complete and partial information retrieval and monitoring accuracy

“…However, assessments of the effects of lorazepam itself are not always consistent. Some authors consider that lorazepam has no effect on short-term memory (Brown et al 1982;Duka et al 1995;Ferrara et al 1999;Fluck et al 1998;Kumar et al 1987;Mac et al 1985;Mallick et al 1993;Matthews et al 2002), whereas others consider that lorazepam induces a deficit in short-term memory (Patat et al 1995). Mintzer and Griffiths (2003) observed an impairment of working memory under the effect of lorazepam, as did Duka et al (1995).…”