Fig. 7.

Response to external input transients. We consider the response of the excitatory population when a 10-ms square input is applied to both excitatory and inhibitory populations. A: results corresponding to postnatal day (P)7 (left) and P13 (right), where model parameters are fixed as in Fig. 2 and Fig. 5, in the absence of noise, for 2 different external stimuli, ΔI_E = 0.5 (top) and ΔI_E = 1.5 (bottom). Solid black lines represent excitatory activity u_E when an external input transient is applied (red solid lines), and dotted lines are the corresponding activity $u_{\text{E}}^0$ for baseline constant input. B: responses at P7 for different onset time t₀ of the transient external stimuli, relative to the instant of previous maximum of activity t_max. C: the color map represents the asymptotic phase shift Φ_t between the excitatory activity response and the unperturbed solution, as a function of the transient amplitude ΔI_E and the initial phase shift ϕ_i. D: maximum difference Δ in activity between perturbed and unperturbed dynamics, for different initial phase shift ϕ_i, in a window of 100 ms from the onset time of the external impulse (P7 and P13 model parameters). E: variance σ of the distribution over ϕ_i as a function of the age of the animal (parameters fixed as in Fig. 5) for different values of ΔI_E. The blue dashed vertical line indicates the moment of the developmental switch, happening between P11 and P12.