SCOPOLAMINE AND LORAZEPAM EXERT DIFFERENT PATTERNS OF EFFECTS IN A TEST BATTERY ASSESSING STAGES OF INFORMATION-PROCESSING

The effects of a single dose of scopolamine (0.5 mg) SC and of lorazep am (2.5 mg) PO were tested in two independent studies for their effect s on performance in a psychometric battery which measured functions re lated to different stages of information processing. Attention and vig ilance were measured by a continuous attention task and a vigilance ta sk, respectively. Working memory and reasoning were evaluated by the r apid information processing and logical reasoning task; memory acquisi tion and storage were measured by pre- and post-drug immediate and del ayed recall using visual material. The following pattern of effects wa s revealed: both scopolamine and lorazepam impaired performance in att entional and vigilance tasks as well as in the rapid information proce ssing task significantly (P < 0.05) when compared with their own place bo; in the logical reasoning task lorazepam significantly prolonged th e time required to solve a problem; scopolamine did not have any effec t on this task. Scopolamine impaired performance in the immediate reca ll but left delayed recall unaffected; lorazepam impaired only delayed recall, immediate recall remaining unaffected. These data suggest; th at 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.