Brain and Behaviour Seminar Series

Exploring circadian activity patterns and sleep in hyper-diverse cichlid fishes

Many of the mechanisms that regulate the phase, duration, and structure of sleep are conserved, yet paradoxically, sleep displays remarkable variation both across and within species. Animals can have different chronotypes (‘early-birds’/‘night-owls’) or spend variable amounts of time asleep (2-18 hrs/day). Species can shift the phase of their activity (nocturnal/diurnal), restrict activity to specific periods (dawn/dusk), or lose rhythmicity entirely. We use multiple fish models to study the genomic, cellular, and evolutionary mechanisms of sleep. Using in lab animal tracking, we have recently identified incredible variation in sleep timing and duration across > 60 species of African cichlid fish from Lake Tanganyika. The diversity observed in these cichlids (10 my of evolution) is equivalent to that seen across all animals, and genome-wide association analysis have identified potential molecular and genetic mechanisms underlying the evolution of nocturnality/diurnality and sleep. Currently in the lab we are following up on these studies, and furthering our exploration of sleep in these fishes. Using hidden markov models we are exploring diversity in sleep states (deep sleep vs light sleep) across species and hope to identify genetic correlates for sleep consolidation and bout structure. Finally, I will also discuss the relationship between environmental factors and social context on the regulation and timing of sleep and activity patterns in shell-dwelling cichlid species. These species live and breed in close association with empty snail shells, and many have highly complex social structures. We have recently identified that both environmental and social cues control activity and sleep patterns in these species, if these factors are missing, individuals switch to nocturnal activity. Based on these studies, we believe that cichlids represent an ideal model clade for studying the evolution and neurobiology of sleep.

Hybrid Zoom link: https://utoronto.zoom.us/j/82448448648

To request for an individual meeting with the speaker, please contact Kaori Takehara (kaori.nishiuchi@utoronto.ca).

Visit https://www.takeharalab.com/bbseminar for further information.