Synchronization-Induced Rhythmicity of Circadian Oscillators in the Suprachiasmatic Nucleus
Figure 3
Synchronization of Damped Oscillators
(A) Simulated evolution of Per/Cry mRNA expression over 48 h of 309 coupled neurons in a 2-D SCN slice with a type 2 coupling (nearest-neighbor coupling; dmax = 3.5, K = 0.9). Dark brown corresponds to a low level of Per/Cry expression, while white corresponds to a high expression.
(B) Time series of ten randomly chosen oscillators from the slice shown in (A).
(C) Time series of ten randomly chosen uncoupled, free-running (dmax = 0, K = 0.9) oscillators.
(D) Distribution of cell-intrinsic periods (black, VL neurons; white, DM neurons; total number of cells, n = 309).
(E) Time series of ten transiently weakly coupled oscillators (dmax = 3.5, K = 0.3 between t = 84 and 168 h; n = 309).
(F) Evolution of ten randomly picked oscillators simulating loss of VPAC2 receptor (f decreasing function of the distance, dmax = 1, K = 0.45, n = 309). The decreasing f (see Equation 15) means that the signal is stronger for autocrine coupling. The thick black lines represent the average output. The resulting period is 24.7 h, and the average period of individual oscillators is 24.6 ± 1.2 h.