Fig. 6. Changes in the activity time after mice were released into DD. (A) Differences between the length of daily activity band and the averaged length of the last 5 days in LD (Da) were calculated for 15 days after released in DD. The value on day 0 indicates the difference between the averaged length and the length on the last day in LD. It took »14 days for the activity band to be fully decompressed when released from LD18:6, whereas no change was detected when released from LD6:18. (B) Daily activity times were calculated for 15 days after released in DD from LD 18:6 (filled circles) and from LD6:18 (open circles). The value on day 0 indicates the activity time on the last day in LD. Two-way repeated-measure ANOVA analysis revealed significant differences (P < 0.01) in activity time with factors time (days in DD), conditions (LD18:6 vs. LD6:18) and time ´ conditions. Data are mean ± SD.

Fig. 7. Anterior and posterior SCN slices and distribution of AVP and VIP immunoreactive cells. (A) Phase-contrast photomicrographs demonstrating the planes of anterior and posterior SCN slices. Broken lines indicate dissected SCN areas for Per1-luc activity monitoring. OC, optic chiasm. (Scale bar: 100 mm.) (B) Double-labeling confocal images of VIP (red) and AVP (green) immunoreactivity in the anterior and posterior SCN. Mice were deeply anesthetized and perfused intracardially with 0.1 M PBS followed by 4% paraformaldehyde in 0.1 M PB. Fluoro images of immunoreactive AVP and VIP were visualized by confocal laser scanning microscopy after incubating with anti-mouse goat IgG conjugated with Alexa 488, and anti-rabbit goat IgG with Alexa 594, respectively. (Scale bar: 100 mm.)

Fig. 8. Temporal distribution of individual circadian peaks. Temporal distribution of individual circadian Per1-luc peaks on day 1 of culture in a total of three SCN slices for each photoperiod. Numbers are the mean and SD. For A_M and A_E groups of the anterior SCN in LD18:6, the average phase was calculated excluding peaks at 11 h.