Fig. 5.

Bifurcation study and contrast response for simple input I _1D (see inset of a) with input gain k _I = 0.01. a Two-parameter bifurcation diagram in terms of sigmoid slope λ and adaptation strength k _α shows qualitatively the same organisation of bifurcation curves as Fig. 3a. b, c Time-traces of the activity p(v, t) indicated by intensity as computed at the corresponding points B and C labelled in a. d Steady-state responses in terms of the activity p(v) at the corresponding points D1 and D2 labelled in a. e Contrast response in terms of normalised peak activity R for simple input (solid curve) fitted to a Naka-Rushton function (dashed curve) as described in Appendix C. The line between D1 and D2 in a is the operating range of the model. The response D1 shown in panel d corresponds to c = 0 and the response D2 in panel d corresponds to c = 1