Abstract
Flowers attract pollinating insects like honeybees by sophisticated compositions of olfactory and visual cues. Using honeybees as a model to study olfactory–visual integration at the neuronal level, we focused on mushroom body (MB) output neurons (MBON). From a neuronal circuit perspective, MBONs represent a prominent level of sensory-modality convergence in the insect brain. We established an experimental design allowing electrophysiological characterization of olfactory, visual, as well as olfactory–visual induced activation of individual MBONs. Despite the obvious convergence of olfactory and visual pathways in the MB, we found numerous unimodal MBONs. However, a substantial proportion of MBONs (32%) responded to both modalities and thus integrated olfactory–visual information across MB input layers. In these neurons, representation of the olfactory–visual compound was significantly increased compared with that of single components, suggesting an additive, but nonlinear integration. Population analyses of olfactory–visual MBONs revealed three categories: (i) olfactory, (ii) visual and (iii) olfactory–visual compound stimuli. Interestingly, no significant differentiation was apparent regarding different stimulus qualities within these categories. We conclude that encoding of stimulus quality within a modality is largely completed at the level of MB input, and information at the MB output is integrated across modalities to efficiently categorize sensory information for downstream behavioural decision processing.
Highlights
Understanding how animal brains produce a behavioural output based on combined multimodal sensory information of a2018 The Authors
Despite the substantial convergence from approximately 170 000 Kenyon cells (KCs) to approximately 400 mushroom body output neurons (MBONs) (425 : 1) [15,17], our results show that unimodal sensory input is still preserved by groups of unimodal MBONs responding to either light or odour stimulation
Our analyses of honeybee MBONs revealed a neuronal correlate of such interactions
Summary
Understanding how animal brains produce a behavioural output based on combined multimodal sensory information of a2018 The Authors. Prevailing scene is a crucial aim in the behavioural neurosciences In past years, this was mainly 2 investigated on the basis of, for instance, a distinct visual [1,2,3] or olfactory [4,5] sensory input. This was mainly 2 investigated on the basis of, for instance, a distinct visual [1,2,3] or olfactory [4,5] sensory input While these studies revealed insight into processing of unimodal information in the brain, in reality neuronal networks are confronted with single modalities at a time. In Drosophila neurons termed MBONs may not exclusively serve as output neurons as some MBON types interconnect within MB sub-regions [16]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
