Decision time and local dynamics in the vicinity of a saddle point. Zero coherence level from A to C. A, Longer reaction time for smaller stimulus strength μ₀. Error bars indicate SD. B, Typical time courses: ramping is faster for larger stimulus strength, μ₀. C, Time constants of saddle-like unstable steady state with different μ₀. For μ₀ > 17 Hz, τ_stable is larger than τ_unstable, whereas the opposite is true for μ₀ < 17 Hz. D, Time constants of the unstable saddle as function of coherence level c′ (μ₀ fixed at 30 Hz). The unstable time constant is essentially constant up to c′ ∼ 70%. The sudden increase in τ_unstable happens just before the bifurcation point at which the saddle coalesces with the less favored attractor and disappears (see Fig. 5).