  Neurons are connected to other neurons by axons and dendrites that conduct
signals with finite velocities, resulting in delays between the firing of a
neuron and the arrival of the resultant impulse at other neurons. Since delays
greatly complicate the analytical treatment and interpretation of models, they
are usually neglected or taken to be uniform, leading to a lack in the
comprehension of the effects of delays in neural systems. This paper shows that
heterogeneous transmission delays make small groups of neurons respond
selectively to inputs with differing frequency spectra. By studying a single
integrate-and-fire neuron receiving correlated time-shifted inputs, it is shown
how the frequency response is linked to both the strengths and delay times of
the afferent connections. The results show that incorporating delays alters the
functioning of neural networks, and changes the effect that neural connections
and synaptic strengths have.
