Impact of correlated inputs to neurons: modeling observations from in vivo intracellular recordings

© The Author(s) 2014. This article is published with open access at Springerlink.com Abstract In vivo recordings in rat somatosensory cortex suggest that excitatory and inhibitory inputs are often cor-related during spontaneous and sensory-evoked activity. Using a computational approach, we study how the interplay of input correlations and timing observed in experiments controls the spiking probability of single neurons. Sev-eral correlation-based mechanisms are identified, which can effectively switch a neuron on and off. In addition, we inves-tigate the transfer of input correlation to output correlation in pairs of neurons, at the spike train and the membrane potential levels, by considering spike-driving and non-spike-driving inputs separately. In particular, we propose a plausible explanation for the in vivo finding that mem-brane potentials in neighboring neurons are correlated, but the spike-triggered averages of membrane potentials preced-ing a spike are not: Neighboring neurons possibly receive an ongoing bombardment of correlated subthreshold back-ground inputs, and occasionally uncorrelated spike-driving inputs