Effects of atropine on human pursuit tracking performance

Intramuscular injections of 2 and 4 mg X 70 kg-1 atropine sulfate were administered to 10 male volunteers. Volunteers performed a pursuit tracking task under two light conditions (daytime and dusk/dawn) at 30 and 150 min after injection. The tracking task consisted of a laboratory-constructed viscous-damped optical simulator of the US Army's Ground Laser Locator Designator system. A scale model Warsaw Pact T-62 tank moved at a constant velocity at a simulated distance of 1 km. Doses of 4 mg X 70 kg-1 of atropine significantly degraded tracking performance at 150 min after injection in daylight and at both 30 and 150 min after injection in dim light. Doses of 2 mg X 70 kg-1 did not degrade performance significantly. The present results suggest that atropine will produce tactically significant performance degradations for up to 3 h after administration.