We study the sequences generated by neuronal recurrence equationsFrom a neuronal recurrence equation of memory size h which describes a cycle of length ρ(m) × lcm(p0, p1, . . ., p -1+ρ(m) ), we construct a set of ρ(m) neuronal recurrence equations whose dynamics describe respectively the transient of length O(ρ(m)×lcm(p0, . . ., p d )) and the cycle of length O(ρ(m)×lcm(p d+1 , . . ., p -1+ρ(m) )) if 0 ≤ d ≤ -2 + ρ(m) and 1 if d = ρ(m) -1.This result shows the exponential time of the convergence of neuronal recurrence equation to fixed points and the existence of the period-halving bifurcation.