Abstract
The optomotor response (OMR) is a position stabilizing reflex to whole-field visual motion, demonstrated by fish instinctually moving to follow alternating black and white stripes. The OMR assay is used to assess the visual function of fish. While researchers have been using the OMR assay for years to evaluate the visual acuity of fish, no standardized methods exist. Therefore, the goal of the present study was to develop a standardized protocol for the measurement of OMR in larval fathead minnows, a common model species in ecotoxicology. Results indicate that OMR is a potential endpoint for the assessment of vision in larval fathead minnows and can be quantified as early as 9 dpf. When running the OMR assay, a 4-min acclimation period should be implemented. There did not appear to be a learning component to response latency; however, high variation in likely impeded the ability to detect significant differences.•Optomotor response of fathead minnow larvae can be quantified as early as 9 dpf.•When running the assay, a 4-min acclimation period should be implemented.•Due to high variation, response latency is not recommended for use as an endpoint.
Highlights
The optomotor response (OMR) is a position stabilizing reflex to whole-field visual motion, demonstrated by fish instinctually moving to follow alternating black and white stripes (Rock and Smith 1986)
The OMR assay is used to assess the visual function of a fish and has been utilized in ecotoxicology research to identify the impacts of various chemicals on visual acuity and behavior [4,5,8]
This study sought to determine: 1) the age at which OMR could be quantified in fathead minnows, 2) the amount of acclimation time needed before recording OMR, 3) whether OMR performance was reproducible between different replicates of fish, 4) what depth of water to use in the OMR chamber, 5) whether position of the OMR chamber influenced fish response, and 6) whether response latency is a useful endpoint for the OMR assay
Summary
The optomotor response (OMR) is a position stabilizing reflex to whole-field visual motion, demonstrated by fish instinctually moving to follow alternating black and white stripes (Rock and Smith 1986). Decreases in following time are thought to indicate reduced visual acuity [10] Another metric used for assessing OMR is the measurement of response latency—the amount of time it takes the fish to respond to a change in the direction of the rotating stripes [11]. The lack of method standardization is exemplified by the variability in the age of fish used, the amount of time a fish is given to acclimate to the OMR chamber, the amount of time the fish spends performing the assay, and in the approaches utilized to quantify the response [2,3,4,5,8]. This study sought to determine: 1) the age at which OMR could be quantified in fathead minnows, 2) the amount of acclimation time needed before recording OMR, 3) whether OMR performance was reproducible between different replicates of fish, 4) what depth of water to use in the OMR chamber, 5) whether position of the OMR chamber influenced fish response, and 6) whether response latency is a useful endpoint for the OMR assay
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
