Silences, Spikes and Bursts: Three-Part Knot of the Neural Code

TL;DR

This paper reviews the evidence for a three-part neural code consisting of silences, spikes, and bursts, highlighting mechanisms and theories that support this ternary coding scheme in neural communication.

Contribution

It introduces and discusses the concept of a three-part neural code, integrating mechanisms and theories that support its role in neural information processing.

Findings

Evidence supports the existence of a ternary neural code.

Mechanisms for burst generation are specialized.

The triad benefits learning and attention processes.

Abstract

When a neuron breaks silence, it can emit action potentials in a number of patterns. Some responses are so sudden and intense that electrophysiologists felt the need to single them out, labeling action potentials emitted at a particularly high frequency with a metonym -- bursts. Is there more to bursts than a figure of speech? After all, sudden bouts of high-frequency firing are expected to occur whenever inputs surge. The burst coding hypothesis advances that the neural code has three syllables: silences, spikes and bursts. We review evidence supporting this ternary code in terms of devoted mechanisms for burst generation, synaptic transmission and synaptic plasticity. We also review the learning and attention theories for which such a triad is beneficial.