Hierarchical models for neural population dynamics in the presence of non-stationarity
This work addresses the need for statistical models to understand neural co-variability and information processing, offering an incremental improvement for neuroscience research.
The authors tackled the problem of modeling neural population activity with non-stationary variability by introducing a hierarchical statistical model that captures multiple time-scale sources, and demonstrated it provides a better account of neural firing structure than stationary models in macaque visual cortex recordings.
Neural population activity often exhibits rich variability and temporal structure. This variability is thought to arise from single-neuron stochasticity, neural dynamics on short time-scales, as well as from modulations of neural firing properties on long time-scales, often referred to as "non-stationarity". To better understand the nature of co-variability in neural circuits and their impact on cortical information processing, we need statistical models that are able to capture multiple sources of variability on different time-scales. Here, we introduce a hierarchical statistical model of neural population activity which models both neural population dynamics as well as inter-trial modulations in firing rates. In addition, we extend the model to allow us to capture non-stationarities in the population dynamics itself (i.e., correlations across neurons). We develop variational inference methods for learning model parameters, and demonstrate that the method can recover non-stationarities in both average firing rates and correlation structure. Applied to neural population recordings from anesthetized macaque primary visual cortex, our models provide a better account of the structure of neural firing than stationary dynamics models.