Synchronisation, Binding, and the Role of Correlated Firing in Fast Information Transmission

Abstract

Does synchronization between action potentials from differ- ent neurons in the visual system play a substantial role in solving the binding problem? The binding problem can be studied quantitatively in the broader framework of the information contained in neural spike trains about some external correlate, which in this case is object configurations in the visual field. We approach this problem by using a mathematical formalism that quantifies the impact of correlated firing in short time scales. Using a power series expansion, the mutual information an ensem- ble of neurons conveys about external stimuli is broken down into firing rate and correlation components. This leads to a new quantification pro- cedure directly applicable to simultaneous multiple neuron recordings. It theoretically constrains the neural code, showing that correlations con- tribute less significantly than firing rates to rapid information processing. By using this approach to study the limits upon the amount of informa- tion that an ideal observer is able to extract from a synchrony code, it may be possible to determine whether the available amount of infor- mation is sufficient to support computational processes such as feature binding.