An Assay for Systematically Quantifying the Vestibulo-Ocular Reflex to Assess Vestibular Function in Zebrafish Larvae

Area of Science:

• Neuroscience
• Developmental Biology
• Otolith research

Background:

• Zebrafish larvae are valuable models for studying vertebrate senses, particularly hearing and balance.
• The transparent nature and genetic tractability of zebrafish aid otic development studies.
• Quantifying the vestibulo-ocular reflex (VOR) in larval zebrafish presents challenges due to their size and experimental requirements.

Purpose of the Study:

• To develop and validate a novel device for quantifying the linear vestibulo-ocular reflex (LVOR) in zebrafish larvae.
• To enable accurate measurement of LVOR evoked by head motion along the earth's horizontal axis.
• To provide a more compact and user-friendly system compared to existing methods.

Main Methods:

• A new VOR testing device featuring a custom larva-shaped chamber was designed.
• The device allows for steady, anesthesia-free immobilization of live zebrafish larvae.
• LVOR was measured in wild-type and morphant zebrafish larvae (dlx3b, dlx4b) to assess system efficacy.

Main Results:

• The developed system successfully quantified linear VOR in zebrafish larvae.
• Measured LVOR amplitudes correlated with otolith morphological changes induced by morpholino oligonucleotides.
• Results demonstrated the system's ability to differentiate between genetic variations affecting otic development.

Conclusions:

• The new VOR testing device offers a significant advancement for otic function research in zebrafish.
• This system facilitates accurate LVOR measurement, crucial for understanding vestibular development and function.
• The device aids in predicting vestibular conditions by correlating VOR with otolith morphology.