Alternating Shrinking Higher-order Interactions for Sparse Neural Population Activity

Abstract: Neurons in living things work cooperatively and efficiently to process incoming sensory information, often exhibiting sparse and widespread population activity involving structured higher-order interactions. While there are statistical models based on continuous probability distributions for neurons' sparse firing rates, how the spiking activities of a large number of interacting neurons result in the sparse and widespread population activity remains unknown. Here, for homogeneous (0,1) binary neurons, we provide sufficient conditions under which their spike-count population distribution converges to a sparse widespread distribution of the population spike rate in an infinitely large population of neurons. Following the conditions, we propose new models belonging to an exponential family distribution in which the sign and magnitude of neurons' higher-order interactions alternate and shrink as the order increases. The distributions exhibit parameter-dependent sparsity on a bounded support for the population firing rate. The theory serves as a building block for developing prior distributions and neurons' non-linearity for spike-based sparse coding.