Temporal organisation of biology: circadian, circatidal, circalunar, circannual rhythms; their molecular bases (clock genes), entrainment, and medical consequences. 2017 Nobel to Hall, Rosbash, Young for molecular circadian mechanism.
chronobiology
Circadian rhythm
Endogenous ~24 h biological oscillation, persisting in constant conditions (free-running period τ ≈ 24.2 h in humans). Entrained by…
Clock genes and TTFL
Transcription–translation feedback loop: CLOCK:BMAL1 heterodimer drives expression of Per, Cry; PER:CRY complexes feed back to inhibit…
Suprachiasmatic nucleus (SCN)
Hypothalamic nucleus above the optic chiasm containing ~20,000 neurons; the master circadian pacemaker of mammals. Directly innervated by…
Melatonin signalling
N-acetyl-5-methoxytryptamine released by the pineal gland at night under SCN control. Signals darkness; feeds back onto SCN (MT1) and…
Entrainment
Phase and period alignment of endogenous oscillator to an external zeitgeber. Phase-response curve Δφ(φ) quantifies advance/delay as a…
Jet lag and shift-work disorder
Acute misalignment between internal circadian phase and external time/activity. Jet lag resolves at ~1 day per time-zone; chronic…
Peripheral clocks
Cell-autonomous molecular clocks in nearly every tissue (liver, muscle, adipose, gut) entrained by SCN output and local cues (food timing,…
Chronopharmacology
Time-of-day dependence of drug efficacy and toxicity. Examples: statins more effective evening (HMG-CoA peaks at night), chemotherapy…
Goodwin 3-variable Hill-feedback: dx/dt=a/(K^n+z^n)−bx; canonical clock oscillator
Goodwin 3-variable Hill-feedback oscillator framework — the canonical minimal-model circadian-clock ODE system and the paradigm for…
Winfree phase response curve: Δφ(φ)=A·sin(φ); sinusoidal entrainment Fourier-mode
Winfree phase-response-curve (PRC) framework — the canonical functional characterisation of how a stimulus at phase φ shifts the phase of a…
Arnold circle map: φ_{n+1}=φ_n+Ω−K·sin(2πφ_n)/(2π); rotation number, Arnold tongues
Arnold circle-map framework — the canonical iterated-map model of periodic-oscillator entrainment, the mathematical foundation of Arnold…
Goodwin: dx/dt=a_g/(K^n+z^n)−b_g·x; symmetric SS s·(s^n+1)=1; n=1: s=(√5−1)/2 (golden)
Sympy-exact symbolic witness of the Goodwin oscillator canonical form, x-nullcline, symmetric-case steady-state equation, and golden-ratio…
PRC: Δφ=A·sin(φ); ∫₀^{2π}Δφdφ=0; Δφ(π/2)=A; tongue width 2εA; φ_lock=arcsin((Ω−ω)/(εA))
Sympy-exact symbolic witness of the Winfree sinusoidal PRC canonical form, zero-mean integral identity, maximum phase shift, 1:1 Arnold…
Arnold map: φ_{n+1}=φ_n+Ω−K·sin(2πφ)/(2π); d_map=1−K·cos(2πφ); λ(K=0)=0
Sympy-exact symbolic witness of the Arnold circle-map canonical iterative form, derivative, and K=0 rigid-rotation anchor. Setup: phi_n,…
Circadian (Pittendrigh 1954)
C Pittendrigh 1954 entrainment + Aschoff Aschoff-rule; modern non-photic-zeitgeber + chronotype.
SCN (Moore-Eichler 1972)
Moore-Eichler 1972 SCN master-clock; modern PER-CRY-CLOCK-BMAL feedback + peripheral-clock entrainment.
Mammalian clock (Takahashi 2017)
J Takahashi 2017 'Transcriptional architecture of the mammalian circadian clock' Nat Rev Genet review.
Chronotherapy (Smolensky 2011)
M Smolensky 2011 chronopharmacology review; modern chemo + statin + corticosteroid timing optimization.
SAD (Rosenthal 1984)
N Rosenthal 1984 seasonal-affective-disorder; modern light-therapy 10,000 lux 30 min; CBT-SAD efficacious.
Konopka-Benzer (1971)
R Konopka-S Benzer 1971 Drosophila per-mutant; foundation molecular-clock genetics; modern Hall-Rosbash-Young Nobel 2017.
Hall-Rosbash-Young (Nobel 2017)
Hall-Rosbash-Young Nobel 2017 per+tim-feedback-loop molecular-clock; modern CLOCK-BMAL1 mammalian core-loop architecture.
Aschoff zeitgeber (1960)
J Aschoff 1960 zeitgeber + free-running τ; modern photoperiod + temperature + feeding entrainment hierarchies.
SCN master clock (Moore 1972)
R Moore-V Eichler 1972 SCN-lesion-abolishes-rhythm; modern peripheral-clock hierarchy + SCN-mediated phase-coherence.
ipRGC (Berson 2002)
D Berson 2002 + S Hattar 2002 melanopsin-expressing ipRGCs; modern non-image-forming photoreception + mood + pupillometry.
TTFL (Takahashi 1997)
J Takahashi 1997 mammalian Clock-gene; modern transcription-translation feedback loop in all kingdoms; chronotherapeutics.
Ruoff-Rensing temperature-compensated Goodwin oscillator extension
Ruoff-Rensing extension (Ruoff-Rensing 1996 *J Theor Biol* 179, 275; Ruoff-Mohsenzadeh-Rensing 1999 *J Biol Rhythms* 14, 469) of the…
Leloup-Goldbeter mammalian molecular-clock model (Per/Cry/Bmal feedback)
Leloup-Goldbeter mammalian-clock model (Leloup-Goldbeter 2003 *PNAS* 100, 7051; refined 2004 *J Theor Biol* 230, 541) is the canonical…