Decorrelated Neuronal Firing in Cortical Microcircuits

TLDR

Neural circuits are presumed to exhibit strong correlations because dense local connectivity provides common input, yet the precise nature of neuronal interactions remains unclear. The study investigates whether the prevailing view of strong neuronal correlations in cortical circuits is accurate. The authors recorded spike trains from pairs of V1 neurons in awake macaques to analyze correlated firing statistics. They found that correlations were very low regardless of stimulus, distance, or receptive field similarity, and modeling showed that zero noise correlation can arise even with common input. The results are reported in Ecker et al.

Abstract

Columns, Connections, and Correlations What is the nature of interactions between neurons in neural circuits? The prevalent hypothesis suggests that dense local connectivity causes nearby cortical neurons to receive substantial amounts of common input, which in turn leads to strong correlations between them. Now two studies challenge this view, which impacts our fundamental understanding of coding in the cortex. Ecker et al. (p. 584 ) investigated the statistics of correlated firing in pairs of neurons from area V1 of awake macaque monkeys. In contrast to previous studies, correlations turned out to be very low, irrespective of the stimulus being shown to the animals, the distances of the recording sites, and the similarity of the neuron's receptive fields or response properties. In an accompanying modeling and recording paper, Renart et al. (p. 587 ) demonstrate how it is possible to have zero noise correlation, even among cells with common input.