The effects of scopolamine on the recall of repeated words: A preliminary investigation

We investigated the effects of scopolamine on the recall of repeated words. Subjects performed continuous recognition memory tasks both before and after the administration of scopolamine, and were asked to recall as many words from the lists as they could immediately after the recognition tasks. Cerebral blood flow was measured by (H2O)-O-15 positron emission tomography during the performance of each task. Scopolamine altered performance on the recall task such that subjects were just as likely to recall words presented once as they were to recall words presented three times. In addition, scopolamine decreased cerebral blood flow during the performance of the task. The extent to which scopolamine decreased cerebral blood how appeared to be associated with the change in performance on the recall task.