Electroretinogram Recording in Larval Zebrafish using A Novel Cone-Shaped Sponge-tip Electrode

Area of Science:

• Neuroscience
• Developmental Biology
• Ophthalmology

Background:

• Zebrafish (Danio rerio) are a key vertebrate model for developmental and visual neuroscience studies.
• Electroretinography (ERG) is a standard non-invasive method for assessing visual function, established in higher vertebrates and increasingly used in zebrafish.
• Current larval zebrafish ERG protocols often rely on glass micropipette electrodes, which are difficult to manufacture and handle, posing a barrier for resource-limited labs.

Purpose of the Study:

• To present a simplified and economical protocol for larval zebrafish electroretinography (ERG).
• To introduce a novel cone-shaped sponge-tip electrode as an alternative to traditional glass micropipette electrodes.
• To demonstrate the utility of this new method for assessing visual function development in larval zebrafish.

Main Methods:

• Development and implementation of a larval zebrafish ERG protocol utilizing a novel cone-shaped sponge-tip electrode.
• Comparison of the novel sponge-tip electrode with traditional glass micropipette electrodes in terms of ease of manufacture, handling, cost, and potential for eye damage.
• Assessment of outer retinal function by measuring photoreceptor (a-wave) and bipolar cell (b-wave) responses.

Main Results:

• The novel sponge-tip electrode is easier to manufacture, handle, more economical, and less damaging to larval zebrafish eyes compared to glass micropipettes.
• The protocol successfully assesses outer retinal function, capturing both a-wave and b-wave responses.
• The method clearly illustrates the refinement of visual function during early zebrafish larval development, confirming its sensitivity and reliability.

Conclusions:

• The cone-shaped sponge-tip electrode offers a practical and accessible alternative for larval zebrafish ERG.
• This simplified approach facilitates the establishment of new ERG systems or modifications of existing setups for zebrafish visual neuroscience research.
• The protocol supports the use of zebrafish as a model organism for studying visual function development and neuroscience.