Abstract:

Several lines of evidence suggest that few or even single spikes carry relevant stimulus information at later stages of sensory processing. Yet mechanisms for the emergence of a robust and temporally sparse sensory representation remain elusive. Here, we introduce an idea in which a temporal sparse and reliable stimulus representation develops naturally in spiking networks. We investigate the role of cellular adaptation – an ubiquitious phenomenon in spiking neurons of vertebrates and invertebrates – on the progressive stimulus representation from peripheral to central stages in the sensory pathway using analytic and computational network models. We report two results: (1) The adaptation effect accumulates across successive processing layers and results in precisely timed stimulus-response spikes. This may facilitate assembly formation e.g. in the sensory cortex. (2) Neuron-instrinsic adaptation transiently suppresses response variability in response to stimulus onset. This is demonstrated for ensembles in the balanced cortical network and in the central insect brain. Our results point to a computational principle that relates neuronal firing rate adaptation to temporal sparse coding and variability suppression in nervous systems.