Colourfulness as a possible measure of object proximity in the larval zebrafish brain

Philipp Bartel,Filip K Janiak,Daniel Osorio,Tom Baden

doi:10.1016/j.cub.2021.01.030

Philipp Bartel, Filip K Janiak + Show 2 more

Open Access

https://doi.org/10.1016/j.cub.2021.01.030

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Journal: Current Biology	Publication Date: Mar 1, 2021
Citations: 17	License type: cc-by

Affiliation: University of Sussex, University of Tübingen

Abstract

SummaryThe encoding of light increments and decrements by separate On- and Off- systems is a fundamental ingredient of vision, which supports edge detection and makes efficient use of the limited dynamic range of visual neurons1. Theory predicts that the neural representation of On- and Off-signals should be balanced, including across an animal’s visible spectrum. Here we find that larval zebrafish violate this textbook expectation: in the zebrafish brain, UV-stimulation near exclusively gives On-responses, blue/green stimulation mostly Off-responses, and red-light alone elicits approximately balanced On- and Off-responses (see also references2, 3, 4). We link these findings to zebrafish visual ecology, and suggest that the observed spectral tuning boosts the encoding of object ‘colourfulness’, which correlates with object proximity in their underwater world5.

Highlights

The encoding of light increments and decrements by separate On- and Offsystems is a fundamental ingredient of vision, which supports edge detection and makes efficient use of the limited dynamic range of visual neurons[1]
Regions of interest corresponding to individual and/ or small groups of responding neuronal somata were extracted from each recording, quality filtered, denoised and decomposed into Onand Off- responses (Figure S1A–G and Supplemental Experimental Procedures)
The UV On- responses likely serve prey-capture of aquatic microorganisms such as paramecia, which appear as UV-bright objects when illuminated by the sun[7]

Summary

Introduction

The encoding of light increments and decrements by separate On- and Offsystems is a fundamental ingredient of vision, which supports edge detection and makes efficient use of the limited dynamic range of visual neurons[1]. To record the entire brain along its natural three-dimensional curvature we used a non-telecentric mesoscale approach coupled with ‘intelligent plane bending’ enabled by rapid remote focusing[6] (Video S1 and Figure S1A). Regions of interest corresponding to individual and/ or small groups of responding neuronal somata were extracted from each recording, quality filtered, denoised and decomposed into Onand Off- responses (Figure S1A–G and Supplemental Experimental Procedures).

Results

Conclusion