p076fig02.25 An on-center off-surround network can respond to increasing on-center excitatory inputs without a loss of sensitivity.  Instead, as the off-surround input increases, the region of a cell's maximal sensitivity to an increasing on-center input shifts to a range of larger inputs. This is because the off-surround divides the effect of the on-center input, an effect that is often called a Weber law.<BR>||  Web er law, adaptation, and shift property (Grossberg 1963).<BR>Convert to logarithmic coordinates:<BR>K = ln(Ii),  Ii = e^K, J = sum[k≠i: Ik]<BR>xi(K,J) = B*Ii/(A + Ii + J) = B*e^K/(A + e^K + J)<BR>x(K + S, J1) = x(K, J2), S = ln((A + J1)/(A + J2)) size of SHIFT.