The long-term evolution of light sensitivity from single-cell organisms to humans: What we are missing now
Evolutionary biologists assume that life arose in the earth's oceans about 3.5 billion years ago. About a billion years later,...
1.06 Non-Photic Influences on the Circadian Timing System
By now you appreciate the powerful effect of light input on circadian rhythms. However, further studies showed that the inner clock can also respond...
1.05 The Spectrum of Light for Activating the Circadian Clock Response
The spectrum of visible light spans the range of violet to blue to green to yellow to orange and red—short to long wavelengths. When...
1.04 The Eye as Light Transducer to the Circadian Clock: Melanopsin as a Circadian Phototransducer
We mentioned before, in Part II (Locating the Circadian Clock in the Brain), that the neural fibers that travel from the eye into the...
1.03 The Effect of Timing of Light Exposure on Circadian Rhythms (Entrainment and Phase-Shifting)
Perhaps the biggest puzzle researchers faced, once they had verified that the inner clock’s cycle differed from the earth’s rotational cycle, was how exposure...
1.02 Locating the Circadian Clock in the Brain
The properties of the inner clock—its free-run under constant lighting or darkness, its entrained response to light-dark cycles—were initially understood at the level of...
1.01 Origins of the Understanding of the Circadian Timing System and Its Free-Running Clock
The amazing field of chronobiology has recently expanded to include applications of its discoveries to treatment (chronotherapy). Nevertheless, chronobiology has its roots in strict...
