OLFACTORY INFORMATION PROCESSING IN INSECTS: PROCESSING IN THE ANTENNAL LOBES

Insects detect small changes in odour concentration at astoundingly low thresholds and recognize and distinguish complex blends of odours. Furthermore, they are able to localize odour sources within short range as well as over long distances. Specialized olfactory receptor neurons on the antennae encode the different properties of odours in their action potential response. Via the axonal projections of olfactory receptor neurons into the antennal lobes the olfactory information is relayed into the deutocerebrum of the midbrain. From the antennal lobes the olfactory information is distributed into protocerebral target areas such as the mushroom bodies and the lateral protocerebrum. What kind of information is encoded in these midbrain regions and how these areas finally connect to locomotor control centers remains largely unknown. Therefore, this paper will concentrate on olfactory information processing in the antennal lobes of moths as the best studied system.