Spike Sorting: Bayesian Clustering of Non-Stationary Data

Abstract

Spike sorting involves clustering spike trains recorded by a micro- electrode according to the source neuron. It is a complicated problem, which requires a lot of human labor, partly due to the non-stationary na- ture of the data. We propose an automated technique for the clustering of non-stationary Gaussian sources in a Bayesian framework. At a first search stage, data is divided into short time frames and candidate descrip- tions of the data as a mixture of Gaussians are computed for each frame. At a second stage transition probabilities between candidate mixtures are computed, and a globally optimal clustering is found as the MAP so- lution of the resulting probabilistic model. Transition probabilities are computed using local stationarity assumptions and are based on a Gaus- sian version of the Jensen-Shannon divergence. The method was applied to several recordings. The performance appeared almost indistinguish- able from humans in a wide range of scenarios, including movement, merges, and splits of clusters.