Conference Paper
The lateral line confers evolutionarily derived sleep loss in the mexican cavefish
Jaggard, J.B., Robinson, B.G., Stahl, B.A., Oh, I., Masek, P., Yoshizawa, M. and Keene, A.C.
Record Number:
3246
Year:
2017
Journal:
AIm 2017
Abstract:
Sleep is an essential behavior exhibited by nearly all animals, and disruption of this process is
associated with an array of physiological and behavioral deficits. While sleep is defined by
changes in sensory gating, where sensory input to the brain is reduced during sleep little is known
about the neural basis for interactions between sleep and sensory processing. The blind Mexican
cavefish is comprised of an extant surface dwelling form and 29 cave morphs that have
independently evolved increased numbers of mechanoreceptive lateral line neuromasts and the
convergent evolution of sleep loss. Ablation of the lateral line enhanced sleep in the Pachón
cavefish population suggesting that heightened sensory input underlies evolutionarily derived
sleep loss. Targeted lateral line ablations and behavioral analysis localized the wake-promoting
neuromasts in Pachón cavefish to superficial neuromasts of the trunk and cranial regions.
Strikingly, lateral line ablation did not affect sleep in four other cavefish populations, suggesting
distinct neural mechanisms regulate the evolution of sleep loss in independently derived cavefish
populations. Cavefish are subject to seasonal changes in food availability, raising the possibility
that sensory modulation of sleep is influenced by metabolic state. We found that starvation
promotes sleep in Pachón cavefish, and this is not enhanced by lateral line ablation, suggesting
functional interactions between sensory and metabolic regulation of sleep. The wake-promoting
neuropeptide, hypocretin/orexin (HCRT) is unregulated in Pachón cavefish, and pharmacological
inhibition of HCRT signaling restores surface-like sleep in Pachón. Both starvation and ablation
of the lateral line curtailed HCRT expression in Pachón cavefish, suggesting that enhanced sensory
signaling promotes HCRT. Taken together, these findings support a model where sensory
processing contributes to evolutionarily derived changes in sleep that are modulated in accordance
with food availability.
Times Cited:
1
Relevent Species: