Table 1
Activity patterns in LD conditions
| (mean ± SEM) | (mean ± SEM) | |||
|---|---|---|---|---|
| ZT10-12 | 8.11 ± 1.13 | 6.85 ± 1.71 | ns |
Phase angle (ψ, difference of activity onset with the time of lights off) and percentage of activity for each ZT interval over total activity were calculated (% Area, see methods for details). P values correspond to Student’s t test between nude (n = 9) and WT (n = 6) control mice. Data are expressed as mean ± SEM.
Figure 1
Activity patterns of nude and WT mice in LD and DD conditions. Representative actograms of nude (left) and wild-type (right) mice under LD (A) and DD (C) conditions. Average waveforms of nude (black) and WT (red) mice for LD (B) and DD (D) condition were calculated using the individual waveforms of relative activity.
Table 2
Activity patterns in DD conditions
| Nude | WT | p | |
|---|---|---|---|
| α/ρ | 0.58 ± 0.06 | 0.98 ± 0.27 | ns |
Free running period (τ), α (time duration of the subjective day) and ρ (time duration of the subjective night) were calculated as described in methods. τ (hours), total α length (hours), α/τ ratio expressed as percentage, (% α/τ), percentage of total activity occurring during α (% Area (α)) and the α/ρ ratio are expressed as mean ± SEM for nude (n = 9) and WT (n = 6) mice. P values correspond to Student’s t test between the two mice groups.
Figure 2
Response to light pulses in nude and WT mice. Athymic nude and control WT mice were subjected to light pulses during the early night (A, B) or the late night (C). A. Representative actograms of general activity of nude and WT mice receiving a light pulse (150 lux, 10 min) at CT15 (Right). No significant difference was found between the two strains (Left, mean ± SEM, -23.2 ± 6.2 min in nude and −20.2 ± 6.0 min in WT mice, n = 6, p > 0.05, Student’s t test). B. Representative actograms of nude and WT mice receiving a light pulse (150 lux, 120 min) at CT14 (Right). No significant difference was found between the two strains (Left, mean ± SEM, -99 ± 6.3 min in nude and −161.3 ± 29.3 min in WT mice, n = 3, p > 0.05, Mann Whitney test). C. Representative actograms of nude and WT mice receiving a light pulse (150 lux, 10 min) at CT22 (Right). No significant difference was found between the two strains (Left, mean ± SEM, 42 ± 31 minutes for nude and 2 ± 12 for WT mice, n = 3, p > 0.05, Mann Whitney test).
Figure 3
Light-induced cFos expression in the SCN of nude and WT mice. A. Mean ± SEM of positive cells number in the ventrolateral (core), dorsomedial (shell) and total areas of the SCN of nude and WT mice 60 min after a 10 min light pulse at CT15 (no significant difference was found between the number of cells either in the core, shell or total areas of the SCN; n = 3, p > 0.05, Mann Whitney test). B. Representative SCN coronal sections illustrating c-Fos expression in nude and WT mice exposed to 10 min light pulse (150 lux) at CT15.
Figure 4
Resynchronization to phase shifts in the light–dark schedule. Nude and WT control mice were subjected to a 6-h shift in the light–dark schedule, and the transient needed to resynchronize to the new schedule was quantified. A. Time (days) needed to reentrain to the light–dark cycle in nude and WT mice subjected to a 6-h phase delay (2.7 ± 0.5 and 1.3 ± 0.2 days for nude and WT, respectively; p > 0.05 Mann Whitney test). B. Transient (days) needed to reentrain after 6-h phase advance of the LD cycle (7.5 ± 0.5 and 5.7 ± 0.2 days for nude and WT, respectively; p > 0.05 Mann Whitney test). C. Representative actograms of nude and WT mice subjected first to a 6-h phase delay and then (15 days later) to a 6-h phase advance of the LD cycle. Grey background represents time of lights-off.