Abstract
Reliable vision in dim light depends on the efficient capture of photons. Moreover, visually guided behaviour requires reliable signals from the photoreceptors to generate appropriate motor reactions. Here, we show that at behavioural low-light threshold, cockroach photoreceptors respond to moving gratings with single-photon absorption events known as ‘quantum bumps’ at or below the rate of 0.1 s−1. By performing behavioural experiments and intracellular recordings from photoreceptors under identical stimulus conditions, we demonstrate that continuous modulation of the photoreceptor membrane potential is not necessary to elicit visually guided behaviour. The results indicate that in cockroach motion detection, massive temporal and spatial pooling takes place throughout the eye under dim conditions, involving currently unknown neural processing algorithms. The extremely high night-vision capability of the cockroach visual system provides a roadmap for bio-mimetic imaging design.
FOOTNOTES
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Author contributions
A.H., K.H., M.V. and M.W. designed the experiments. A.H. performed the experiments and analyzed the data. J.T. wrote the software used in the experiments and data analyses, made the stimuli and contributed to the data analyses. A.H., M.V. and M.W. wrote the manuscript.
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Competing interests
The authors declare no competing financial interests.
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Funding
This work was supported by funding from Biocenter Oulu Doctoral Programme to A.H.; from Academy of Finland to M.V. and M.W.; from Sigrid Juselius Foundation to M.W.; and from Wihuri Foundation to J.T.
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Supplementary material
Supplementary material available online at http://jeb.biologists.org/lookup/suppl/doi:10.1242/jeb.112425/-/DC1
- © 2014. Published by The Company of Biologists Ltd