Unitary Events in Multiple Single-Neuron Spiking Activity: I. Detection and Significance

TLDR

Cortical neurons are thought to form dynamic functional groups, or cell assemblies, through the temporal structure of their joint spiking activity. The authors present a novel method for detecting conspicuous patterns of coincident joint spike activity among simultaneously recorded single neurons, and outline an extension to handle nonstationary firing rates. Statistical significance of these unitary events is assessed with joint‑surprise, and the method is validated and calibrated on simulated stationary spike trains with inserted coincident events, while sensitivity and specificity are examined across firing rates, coincidence precision, pattern complexity, and temporal resolution.

Abstract

It has been proposed that cortical neurons organize dynamically into functional groups (cell assemblies) by the temporal structure of their joint spiking activity. Here, we describe a novel method to detect conspicuous patterns of coincident joint spike activity among simultaneously recorded single neurons. The statistical significance of these unitary events of coincident joint spike activity is evaluated by the joint-surprise. The method is tested and calibrated on the basis of simulated, stationary spike trains of independently firing neurons, into which coincident joint spike events were inserted under controlled conditions. The sensitivity and specificity of the method are investigated for their dependence on physiological parameters (firing rate, coincidence precision, coincidence pattern complexity) and temporal resolution of the analysis. In the companion article in this issue, we describe an extension of the method, designed to deal with nonstationary firing rates.