Scopolamine impairs object exploration but not habituation in rats.

Memory of a novel object was examined in saline (Sal) and scopolamine (Scopo) treated rats (1.0 mg/kg). Scopo rats showed lower overall exploration time than Sal rats, resulting mainly from shorter durations per contact. In a second exposure to the same object, after 1 min or 20 min interval, both groups displayed marked decrease of exploration indicating between-session habituation. The shorter time spent by Scopo rats on investigation of an object during a single approach might be interpreted as a deficit in maintenance of attention. Nevertheless, Scopo rats were able to acquire sufficient information for the retention during 20 min interval, as indicated by habituation, which is an elementary index of memory.