CD-1 mice were monitored over a period of 15 days after i.n. application (indicated by arrow) of ricin (1.7 μg/kg) or PBS (sham treatment): circles, body weight of LDR (black) and sham (white) mice, squares: nocturnal motor activity profiles of LDR (black) and sham (white) mice. Body weights are expressed as a percentage of original weight determined at the time of ricin or sham administration. Data represent mean ± SEM, n = 6; nocturnal activity is expressed as percentage of activity determined prior to treatment. Data represent mean ± SEM of cage activity, n = 4 cages, 6 mice per cage.