Functional two-way analysis of variance and bootstrap methods for neural synchrony analysis

Abstract

BackgroundPairwise association between neurons is a key feature in understanding neural coding. Statistical neuroscience provides tools to estimate and assess these associations. In the mammalian brain, activating ascending pathways arise from neuronal nuclei located at the brainstem and at the basal forebrain that regulate the transition between sleep and awake neuronal firing modes in extensive regions of the cerebral cortex, including the primary visual cortex, where neurons are known to be selective for the orientation of a given stimulus. In this paper, the estimation of neural synchrony as a function of time is studied in data obtained from anesthetized cats. A functional data analysis of variance model is proposed. Bootstrap statistical tests are introduced in this context; they are useful tools for the study of differences in synchrony strength regarding 1) transition between different states (anesthesia and awake), and 2) affinity given by orientation selectivity.ResultsAn analysis of variance model for functional data is proposed for neural synchrony curves, estimated with a cross-correlation based method. Dependence arising from the experimental setting needs to be accounted for. Bootstrap tests allow the identification of differences between experimental conditions (modes of activity) and between pairs of neurons formed by cells with different affinities given by their preferred orientations. In our test case, interactions between experimental conditions and preferred orientations are not statistically significant.ConclusionsThe results reflect the effect of different experimental conditions, as well as the affinity regarding orientation selectivity in neural synchrony and, therefore, in neural coding. A cross-correlation based method is proposed that works well under low firing activity. Functional data statistical tools produce results that are useful in this context. Dependence is shown to be necessary to account for, and bootstrap tests are an appropriate method with which to do so.

Mediation of Sinusoidal Network Oscillations in the Locus Coeruleus of Newborn Rat Slices by Pharmacologically Distinct AMPA and KA Receptors

“…Indeed, NMDA increased LC network synchrony in our latter study, whereas no cross-correlation function estimate value could be quantified previously for any neuron during CNQX [ 27 ], as also found here for both AMPA and KA. Thus, a different type of (correlation) analysis needs to be applied in future studies testing AMPAR or KAR activation; e.g., activities of neuron pairs can be correlated as in other network synchrony studies [ 25 , 48 , 49 , 50 , 51 , 52 ]. Nevertheless, it can be concluded that TARP-AMPAR complex activation increases the phase-lock of LC spiking as both agonists decreased the LFP burst duration and single neuron spike jitter.…”