Figure 1
The irradiance spectrum of a red LED integrated into the passive-infrared motion sensor circuitry.
Figure 2
Double-plotted actograms of C57BL/6 mice under DD and dim red LEDfb. Lighting conditions are shown to the right of each actogram.
Figure 3
The circadian period of C57BL/6 mice is longer under dim red LEDfb than DD conditions (p = 0.0095). Lines show the mean period for each group.
Figure 4
Double-plotted actograms of C57BL/6 mice under DD, dim red LEDfb, and LEDs covered with black tape. Lighting conditions are shown to the right of each actogram. Arrows show onset of new lighting conditions.
Figure 5
Circadian period of C57BL/6 mice is longer under dim red LEDfb than when the light source is covered by black tape (p < 0.01) or DD (p < 0.025). Lines show the mean period for each group.
Figure 6
Double plotted actograms of DBA/2 and C57BL/6 mice under DD (top) and dim red LEDfb (bottom). The actograms at top and bottom are from one DBA/2 mouse (left) and one C57BL/6 mouse (right). Lighting conditions were separated by two weeks of LD 12:12.
Figure 7
The circadian period of both DBA/2 and C57BL/6 mice under DD (filled symbols) and dim red LEDfb (open symbols). Lines show the mean period for each group. Overall, mice had longer period under LEDfb than DD (p < 0.025), and C57BL/6 mice had longer periods than DBA/2 mice (p < 0.01).