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Full-Text Articles in Biochemistry, Biophysics, and Structural Biology

A Phylogenetic Analysis Of The Correlates Of Sleep In Birds, Timothy Roth, John Lesku, Charles Amlaner, Steven Lima Nov 2006

A Phylogenetic Analysis Of The Correlates Of Sleep In Birds, Timothy Roth, John Lesku, Charles Amlaner, Steven Lima

Charles J. Amlaner

Quantitative comparative studies of sleep have focused exclusively on mammals. Such studies have repeatedly found strong relationships between the time spent in various sleep states and constitutive variables related to morphology, physiology, and life history. These studies influenced the development of several prominent hypotheses for the functions of sleep, but the applicability of these patterns and hypotheses to non-mammalian taxa is unclear. Here, we present the first quantitative analysis of sleep in a non-mammalian taxon (birds), focusing on the daily amount of time spent in slow-wave sleep (SWS) and rapid-eye movement (REM) sleep as determined by electrophysiological methods. We examined ...


A Phylogenetic Analysis Of Sleep Architecture In Mammals: The Integration Of Anatomy, Physiology, And Ecology, John Lesku, Timothy Roth, Charles Amlaner, Steven Lima Sep 2006

A Phylogenetic Analysis Of Sleep Architecture In Mammals: The Integration Of Anatomy, Physiology, And Ecology, John Lesku, Timothy Roth, Charles Amlaner, Steven Lima

Charles J. Amlaner

Among mammalian species, the time spent in the two main "architectural" states of sleep-slow-wave sleep (SWS) and rapid-eye-movement (REM) sleep-varies greatly. Previous comparative studies of sleep architecture found that larger mammals, those with bigger brains, and those with higher absolute basal metabolic rates (BMR) tended to engage in less SWS and REM sleep. Species experiencing a greater risk of predation also exhibited less SWS and REM sleep. In all cases, however, these studies lacked a formal phylogenetic and theoretical framework and used mainly correlational analyses. Using independent contrasts and an updated data set, we extended existing approaches with path analysis ...


Asynchronous Eye Closure As An Anti-Predator Behavior In The Western Fence Lizard (Sceloporus Occidentalis), Christian Mathews, John Lesku, Stephen Lima, Charles Amlaner Feb 2006

Asynchronous Eye Closure As An Anti-Predator Behavior In The Western Fence Lizard (Sceloporus Occidentalis), Christian Mathews, John Lesku, Stephen Lima, Charles Amlaner

Charles J. Amlaner

Asynchronous eye closure (ASEC), one eye open while the other is closed, is a behavior observed in birds, some aquatic mammals, and reptiles. In birds and aquatic mammals, ASEC is associated with unihemispheric sleep wherein the cerebral hemisphere contralateral to (i.e. neurologically connected to) the closed eye sleeps while the other cerebral hemisphere remains awake with its associated eye open and functional. Evidence from birds suggests that ASEC is an important anti-predator adaptation to mediate the trade-off between the need to remain vigilant and the need to sleep. However, the anti-predator correlates of ASEC remain largely unstudied in other ...