  In biological systems, information is frequently transferred with Poisson
like spike processes (shot noise) modulated in time by information-carrying
signals. How then to quantify information transfer for the output for such
nonstationary input signals of finite duration? Is there some minimal length of
the input signal duration versus its strength? Can such signals be better
detected when immersed in noise stemming from the surroundings by increasing
the stochastic intensity? These are some basic questions which we attempt to
address within an analytical theory based on the Kullback-Leibler information
concept applied to random processes.
