p634fig17.06 Summing over a population of cells with binary output signals whose firing thresholds are Gaussianly distributed (left image) generates a total output signal that grows in a sigmoidal fashion with increasing input size (dashed vertical line).<BR>||  How binary cells with a Gaussian distribution of output thresholds generates a sigmoidal population signal.  [# of binary cells with threshold T, Total output signal] vs Cell firing thresholds T.  Cell population with firing thresholds Gaussianly distributed around a mean value.  As input increases (dashed line), more cells in population fire with binary signals.  Total population output obeys a sigmoid signal function f.