Fig. 2. Regained circadian rhythmic locomotor activity in optic lobe-less cockroaches after transplantation of one accessory medulla into the antennal lobe (animal ID 13/84; Table 2). (A) Double-plot activity histograms show circadian wheel-running activity (=24.2 h) in constant darkness before the operation (B; day 34–39, ²-periodogram). The operated cockroach is arrhythmic for 101 days after the operation, as shown in the ²-periodogram (C; day 58–65). Then, the cockroach regains rhythmic activity with =23.7 h, as shown in the ²-periodogram analysis (D; day 142–148; periodogram peak height=40.7%, width=1 h). Additionally, two activity plots show the mean locomotor activity ± S.D. of the animal during the course of a circadian day before (E; day 34–39) and after (F; day 142–148) the transplantation. Histological data of this animal are shown in Fig. 4C,D.