  Most neurons in peripheral sensory pathways initially respond vigorously when
a preferred stimulus is presented, but adapt as stimulation continues. It is
unclear how this phenomenon affects stimulus representation in the later stages
of cortical sensory processing. Here, we show that a temporally sparse and
reliable stimulus representation develops naturally in a network with adapting
neurons. We find that cellular adaptation plays a critical role in the
transient reduction of the trial-by-trial variability of cortical spiking,
providing an explanation for a wide-spread and hitherto unexplained phenomenon
by a simple mechanism. In insect olfaction, cellular adaptation is sufficient
to explain the emergence of the temporally sparse and reliable stimulus
representation in the mushroom body, independent of inhibitory mechanisms. Our
results reveal a computational principle that relates neuronal firing rate
adaptation to temporal sparse coding and variability suppression in nervous
systems with a sequential processing architecture.
