Circadian Rhythm of Spontaneous Activity. Mean (±SEM, n = 6 pairs) counts per minute (cpm) by undisturbed mice, housed in pairs per home cage (sensor rate 20 Hz). Nocturnal (upper panel) and diurnal (lower panel) activity was recorded for 3 days (PND 51–53), five days after the boost with DAT fragment (DAT-i) or VEH. The 24-h profile of one-hour points was then obtained by averaging the 3 days of continuous registration. * p < 0.05 between DAT-i and VEH control group; # p < 0.05, compared to the previous or the following 1-h point within the same immunization group.