Role of correlations in population coding

Abstract

Correlations among spikes, both on the same neuron and across neurons, are ubiquitous in the brain. For example, cross-correlograms can have large peaks, at least in the periphery (Rodieck, 1967; Mastronarde, 1983a, b; Dan et al., 1998; Nirenberg et al., 2001), and smaller-but still nonnegligible-ones in cortex (see Cohen and Kohn, 2011 for a review), and auto-correlograms almost always exhibit nontrivial temporal structure at a range of timescales (Kim et al., 1990; Bair et al., 2001; Deger et al., 2012). Although this has been known for over 40 years, it is still not clear what role these correlations play in the brain-and, indeed, whether they play any role at all. The goal of this chapter is to shed light on this issue.