Abstract-Current experimental techniques impose spatial limits on the number of neuronal units that can be recorded in-vivo. To model the neural dynamics utilizing these sampled data, Latent Variable Models (LVMs) have been proposed to study the common unobserved processes within the system that drives neural activities, through an implicit network with hidden states. Yet, relationships between these latent variable models and widely-studied network connectivity measures remained unclear. In this paper, a biologically plausible latent variable model was first fit to neural activity recorded via 2-photon microscopic calcium imaging in the murine primary visual cortex. Graph theoretic measures were then applied to quantify network properties in the recorded sub-regions. Comparison of weighted network measures with LVM prediction accuracy shows some network measures having a strong relationship with LVM prediction accuracy, while other measures do not have a robust relationship with LVM prediction accuracy. Results show LVM will achieve high accuracy in dense networks.
I. INTRODUCTIONSince the late 1950s, analyses of in-vivo single-unit recordings in the primary visual cortex have focused on correlating activity of individual neurons with observable features of visual stimuli [8]. However, not all neurons can be confidently classified as maximally responding to a single stimulus feature. Anatomically, it is known that primary sensory regions receive inputs from areas not involved with the stimuli of interest [4]. Imaging techniques have made it possible to record the activity of many neurons simultaneously, in-vivo, while an animal is awake [6]. Applying graph theoretic tools on these high-volume simultaneous recordings allows for novel analyses of brain networks. Graph theory can efficiently characterize network types and elucidate important network properties [1]. For example, in the study of sensory perception, this confluence of techniques allows for a change from pairwise associations between individual sensory neurons and sensory stimuli, to network-level measures of sensory representation. Conventional graph-theoretic measures have often evaluated the explicit network where nodes and edges correspond to neuronal units recorded and statistical dependences between these neurons respectively [1]. Yet, the explicit neuronal population dynamics could be modulated by latent variables or implicit network with unobservable nodes and edges, where the implicit activities were not recorded [5]. Therefore, it is plausible that insights into the function of sensory areas can be gained from application of modelling techniques with reduced assumptions on the computational properties of neuronal networks. Recent research on latent variable models provides the mathematical techniques for such models with limited assumptions [7]. One biologically plausible model, rectified latent variable model (RLVM), has been shown to accurately predict the activity of neurons in the rat barrel cortex [11]. Through simulation and applicatio...