Neural Dynamics, Oscillatory Synchronisation, and Odour Codes

Abstract

Years of productive research examining insect olfaction have revealed numerous important functional and organisational features of the antennal lobe (AL), as described throughout this volume. Recent advances in techniques for simultaneously monitoring the activities of multiple neurons have revealed another important fact about the AL, that its dynamics act to coordinate large numbers of olfactory interneurons so that, when processing odorants, many of them oscillate in synchrony. The effect of this coherent neural activity is surprisingly powerful: it enables the AL to encode odour information in time. We will summarise here experimental results suggesting that, in insects, essential information about odour quality is indeed conveyed not only by the identity of activated neurons (a spatial pattern), but also by the temporal patterns of their odour responses relative to a common time base, the oscillatory ensemble activity.