Sleep Behavior Analysis in Astyanax mexicanus

Sleep is a highly conserved behavior that is nearly ubiquitous throughout the animal kingdom. In recent years, the application of behavioral criteria to define sleep has allowed for the characterization of sleep in many novel species, including models of evolution. Over the past decade, the Mexican tetra (Astyanax mexicanus) emerged as a key model for dissecting the evolutionary, ecological, and neural factors that underlie naturally occurring variation in sleep. Eyed river-dwelling “surface” populations inhabit rivers throughout Mexico, while at least 30 cave populations exist in Northeast Mexico, and many have evolved shared morphological and behavioral traits including albinism, eye loss, as well as differences in social and foraging behaviors. In addition, multiple cave populations have converged on loss of sleep and circadian locomotor rhythms, providing a model to study the evolution of these behaviors. In this chapter, we describe a protocol that enables high-throughput sleep and activity phenotyping using inexpensive camera setups and automated behavioral tracking. Using this system, researchers can quantify sleep in both surface fish and cave fish beginning as young as 4 days postfertilization. The data processing pipeline results in sleep and activity profiles across the daily cycle. This protocol may also serve as a guide for creating similar sleep quantification setups in other fish or aquatic taxa.