Sleep deprivation in zebrafish larvae: Behavior and cognitive alterations

Sleep deprivation, characterized by insufficient sleep, leads to reduced performance and alertness. In zebrafish, sleep follows a diurnal circadian rhythm marked by periods of inactivity and progressive arousal. Considering the importance of sleep during early developmental stages and its potential long-term effects, we evaluated the impact of partial sleep deprivation (PSD) and total sleep deprivation (TSD) in zebrafish larvae, as well as their consequences on adult behavior and memory. At 5 days post-fertilization (dpf), larvae were exposed to prolonged light exposure for three consecutive days. PSD was induced by extending the light phase to 19 h with 5 h of darkness, and TSD protocol consisted of continuous light exposure for 24 h. During the protocols, exploratory, aversive, and optomotor behaviors were assessed. Afterward, fish were kept under a standard light/dark cycle until 180 dpf, when locomotion, social interaction, and memory were analyzed. Larvae subjected to 48 h of PSD showed decreased distance traveled and swimming velocity. TSD reduced distance and movement at 24, 48, and 72 h, as well as velocity at 24 and 72 h. Moreover, 72 h of PSD and 48 and 72 h of TSD impaired optomotor behavior. However, at 180 dpf, neither PSD nor TSD altered locomotion, social interaction, or memory. These findings indicate that both PSD and TSD impair locomotion and optomotor response during early development, but behavioral changes related to locomotion, social interaction, and memory are not observed in adulthood.