Asymmetric odour coding in the honeybee antennal lobe

Left-right asymmetric processing is a common property of nervous systems. It is thought that lateralization serves to avoid functional incompatibilities between sensory representations and to increase coding capacity by parallel processing. Lateralized sensory processing has mainly been described at behavioral or anatomical level while asymmetric neuronal coding is less studied. We identified a left-right asymmetry in the honeybees antennal lobes during odour processing. When odours were symmetrically puffed to the antennae, the neurophysiological distances between odours in the right antennal lobe were higher than in the left one. Moreover, mixture processing differed between sides: inhibitory interactions occurred mainly in the left antennal lobe, while additive processing occurred mainly in the right antennal lobe. We propose a functional specialization between the antennal lobes with the right being tuned for fine odour discrimination. Behavioural data support this hypothesis: bees with amputated right antenna failed in an olfactory discrimination task, while bees with amputated left antenna succeeded