Learning temporal clusters with synaptic facilitation and lateral inhibition

Short-term synaptic plasticity has been proposed as a way for cortical neurons to process temporal information. We present a model network that uses shortterm plasticity to implement a temporal clustering algorithm. The model’s facilitory synapses learn temporal signals drawn from mixtures of nonlinear processes. Units in the model correspond to populations of cortical pyramidal cells arranged in columns; each column consists of neurons with similar spatiotemporal receptive fields. Clustering is based on mutual inhibition similar to Kohonen’s SOMs. A generalized expectation maximization (GEM) algorithm, guaranteed to increase model likelihood with each iteration, learns the synaptic parameters.