Figure 4.

(a–d) Response of designs I–IV to sinusoidal inputs. For each model described in figure 2, we applied a small amplitude sinusoidal stimulus and recorded the model's response amplitude (maximum–minimum of x (designs I and II) M (design III) or U (design IV) after initial transients; (a(i)–d(i)) resonator and (a(ii)–d(ii)) integrator). The rate constants that showed resonance in figure 2 displayed a maximum response amplitude at a particular frequency, w. The response amplitude for integrator models decreased as the frequency increased (with the exception of IV that is discussed in the text). For resonator and integrator design I, Δ=30+sin (wt) or Δ=9.5+0.1 sin (wt), respectively. For resonator and integrator design II, Δ=20+0.1 sin (wt) or Δ=3.6+0.01 sin (wt), respectively. For resonator and integrator design III, k_p1=20+0.1 sin (wt) or k_p1=30+0.1 sin (wt), respectively. For resonator and integrator design IV, α₁=1.72+0.01 sin (wt) or α₁=2.4+0.01 sin (wt), respectively. All other parameters are the same as given in figure legend 2.