Figure 3

Gain control (9) as a function of activity A. The function \(l(A)\), in dashed line, is a piecewise linear approximation of \({\mathcal {G}}_{B}(A)\) from which three regions are roughly defined. In the region “Silent” the gain vanishes so the cell does not respond to stimuli; in the region “Max”, the gain is maximal so that cell behaviour does not show any difference with a not gain-controlled cell; the region “Fast decay” is the one which contributes to anticipation by shifting the peak in the cell’s activity (see Sect. 3.1). The value \(A_{c}=\frac{2}{3}\) corresponds to the value of activity where gain control, in the piecewise linear approximation, becomes effective