Multimodal interaction in the insect brain.

Anna Balkenius,Christian Balkenius

doi:10.1186/s12868-016-0258-7

Anna Balkenius, Christian Balkenius

Open Access

https://doi.org/10.1186/s12868-016-0258-7

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Abstract

BackgroundThe magnitude of multimodal enhancement in the brain is believed to depend on the stimulus intensity and timing. Such an effect has been found in many species, but has not been previously investigated in insects.ResultsWe investigated the responses to multimodal stimuli consisting of an odour and a colour in the antennal lobe and mushroom body of the moth Manduca sexta. The mushroom body shows enhanced responses for multimodal stimuli consisting of a general flower odour and a blue colour. No such effect was seen for a bergamot odour. The enhancement shows an inverse effectiveness where the responses to weaker multimodal stimuli are amplified more than those to stronger stimuli. Furthermore, the enhancement depends on the precise timing of the two stimulus components.ConclusionsInsect multimodal processing show both the principle of inverse effectiveness and the existence of an optimal temporal window.Electronic supplementary materialThe online version of this article (doi:10.1186/s12868-016-0258-7) contains supplementary material, which is available to authorized users.

Highlights

The magnitude of multimodal enhancement in the brain is believed to depend on the stimulus intensity and timing
In experiment 1, the response magnitude for BM decreased in antennal lobe (AL) when the odour concentration was lowered (Linear regression, r2 = 0.5016, P < 0.001, Additional file 1)
We investigated the multimodal responses of the brain of the moth M. sexta to stimuli consisting of odours and colours of different intensities in different temporal relationships to test the principle of inverse effectiveness and the temporal window of multimodal integration

Summary

Introduction

The magnitude of multimodal enhancement in the brain is believed to depend on the stimulus intensity and timing. Such an effect has been found in many species, but has not been previously investigated in insects. It is well known that information from different sensory channels is combined and integrated in the nervous system. This results in a robust and unified perception of the external world, and provides animals with considerable response flexibility [1, 2].

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