iScience
Volume 7, 28 September 2018, Pages 85-95
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Article
Glutamate Signaling in the Fly Visual System

https://doi.org/10.1016/j.isci.2018.08.019Get rights and content
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Highlights

  • The glutamate sensor iGluSnFR is suitable for 2-photon imaging in the fruit fly

  • Response properties obtained with iGluSnFR are much faster than those with GCaMP6f

  • Spatial aspects of receptive fields are preserved between indicators

Summary

For a proper understanding of neural circuit function, it is important to know which signals neurons relay to their downstream partners. Calcium imaging with genetically encoded calcium sensors like GCaMP has become the default approach for mapping these responses. How well such measurements represent the true neurotransmitter output of any given cell, however, remains unclear. Here, we demonstrate the viability of the glutamate sensor iGluSnFR for 2-photon in vivo imaging in Drosophila melanogaster and prove its usefulness for estimating spatiotemporal receptive fields in the visual system. We compare the results obtained with iGluSnFR with the ones obtained with GCaMP6f and find that the spatial aspects of the receptive fields are preserved between indicators. In the temporal domain, however, measurements obtained with iGluSnFR reveal the underlying response properties to be much faster than those acquired with GCaMP6f. Our approach thus offers a more accurate description of glutamatergic neurons in the fruit fly.

Subject Areas

Optical Imaging
Sensory Neuroscience
Techniques in Neuroscience

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