Six Lectures on the Fundamental Properties of Circadian Clocks

The videos below are six lectures on the fundamental properties of circadian rhythms, recorded by Carl Hirschie Johnson during the autumn of 2020. You’ll learn about the defining properties of circadian programs, most prominently about the free-running period (FRP), temperature compensation, and entrainment. Along the way, we will also discuss “Aschoff’s Rule,” the ”Gating Hypothesis,” aftereffects, Phase Response Curves (PRCs), Multiple Oscillators, Limit Cycle Oscillators, and entrainment to photoperiods/seasons. At the end of these lectures, you will know why we think the FRP is not exactly equal to 24 hours, in other words, why circadian programs are “CIRCA”-dian !

Please see this guide for more information on the videos below. 

1. Fundamental Properties of Circadian Clocks: the free-running period (𝝉, FRP), Aschoff’s “Rule,” the “Gating Hypothesis,” et al.

2. Fundamental Properties of Circadian Clocks: Temperature compensation, Introduction to Phase Response Curves (PRCs), et al.

3. Multiple Oscillators: the A/B model, splitting, et al.

4. Entrainment I: the Discrete Model of entrainment, One-pulse Entrainment, et al.

5. Limit Cycle Oscillators: Phase Planes, Isochrons, Type 1 vs. Type 0 resetting, et al.

6. Entrainment II: Entrainment to Photoperiods/Seasons, why isn’t 𝝉 = 24 hours, et al.