Abstract
The goal of this article is to develop a novel statistical model for studying cross-neuronal spike train interactions during decision-making. For an individual to successfully complete the task of decision-making, a number of temporally organized events must occur: stimuli must be detected, potential outcomes must be evaluated, behaviors must be executed or inhibited, and outcomes (such as reward or no-reward) must be experienced. Due to the complexity of this process, it is likely the case that decision-making is encoded by the temporally, precise interactions between large populations of neurons. Most existing statistical models, however, are inadequate for analyzing such a phenomenon because they provide only an aggregated measure of interactions over time. To address this considerable limitation, we propose a dynamic Bayesian model that captures the time-varying nature of neuronal activity (such as the time-varying strength of the interactions between neurons). The proposed method yielded results that reveal new insight into the dynamic nature of population coding in the prefrontal cortex during decision-making. In our analysis, we note that while some neurons in the prefrontal cortex do not synchronize their firing activity until the presence of a reward, a different set of neurons synchronizes their activity shortly after stimulus onset. These differentially synchronizing subpopulations of neurons suggest a continuum of population representation of the reward-seeking task. Second, our analyses also suggest that the degree of synchronization differs between the rewarded and nonrewarded conditions. Moreover, the proposed model is scalable to handle data on many simultaneously recorded neurons and is applicable to analyzing other types,of multivariate time series data with latent structure. Supplementary materials (including computer codes) for our article are available online.