  The effect of a temporally correlated afferent current on the firing rate of
a leaky integrate-and-fire (LIF) neuron is studied. This current is
characterized in terms of rates, auto and cross-correlations, and correlation
time scale $\tau_c$ of excitatory and inhibitory inputs. The output rate
$\nu_{out}$ is calculated in the Fokker-Planck (FP) formalism in the limit of
both small and large $\tau_c$ compared to the membrane time constant $\tau$ of
the neuron. By simulations we check the analytical results, provide an
interpolation valid for all $\tau_c$ and study the neuron's response to rapid
changes in the correlation magnitude.
