Ostriches Sleep like Platypuses

Lesku, John A.; Meyer, Leith C. R.; Fuller, Andrea; Maloney, Shane K.; Dell’Omo, Giacomo; Vyssotski, Alexei L.; Rattenborg, Niels Christian

doi:10.1371/journal.pone.0023203

Cited by 86 publications

(86 citation statements)

References 55 publications

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“…[5][6][7][8][9][10][11][12][13] Our findings go beyond cortical measures to find hippocampal sleep state differences and extend SWS/ waking intracortical discrepancies to include TR and REM sleep heterogeneities. Hints of REM heterogeneities have been found in monotremes 33 and ostriches 2,34 : the neocortex may show EEG slow waves whereas other parameters controlled by subcortical brain structures may show aspects of REM sleep (rapid eye movements and muscle atonia). Future studies could assess other subcortical areas and physiological signals other than EEG that are known to change with sleep state, such as respiratory and heart rate, to determine whether these variables more closely align with the hippocampal, cortical, or other subcortical EEG states.…”

Section: Discussionmentioning

confidence: 99%

Different Simultaneous Sleep States in the Hippocampus and Neocortex

Emrick

Gross

Riley

et al. 2016

Sleep

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Study Objectives: Investigators assign sleep-waking states using brain activity collected from a single site, with the assumption that states occur at the same time throughout the brain. We sought to determine if sleep-waking states differ between two separate structures: the hippocampus and neocortex. Methods: We measured electrical signals (electroencephalograms and electromyograms) during sleep from the hippocampus and neocortex of five freely behaving adult male rats. We assigned sleep-waking states in 10-sec epochs based on standard scoring criteria across a 4-h recording, then analyzed and compared states and signals from simultaneous epochs between sites. Results: We found that the total amount of each state, assigned independently using the hippocampal and neocortical signals, was similar between the hippocampus and neocortex. However, states at simultaneous epochs were different as often as they were the same (P = 0.82). Furthermore, we found that the progression of states often flowed through asynchronous state-pairs led by the hippocampus. For example, the hippocampus progressed from transitionto-rapid eye movement sleep to rapid eye movement sleep before the neocortex more often than in synchrony with the neocortex (38.7 ± 16.2% versus 15.8 ± 5.6% mean ± standard error of the mean). Conclusions: We demonstrate that hippocampal and neocortical sleep-waking states often differ in the same epoch. Consequently, electrode location affects estimates of sleep architecture, state transition timing, and perhaps even percentage of time in sleep states. Therefore, under normal conditions, models assuming brain state homogeneity should not be applied to the sleeping or waking brain.

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Section: Discussionmentioning

confidence: 99%

Different Simultaneous Sleep States in the Hippocampus and Neocortex

Emrick

Gross

Riley

et al. 2016

Sleep

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“…The Auk: Ornithological Advances 132:119-131, Q 2015 American Ornithologists' Union contrast to many herbivorous mammals, these herbivorous birds, as well as poultry and waterfowl (Mench 2009), are basically inactive at night yet have similar overall daily food intakes ( Figure 3A), a phenomenon that has, to our knowledge, rarely been addressed yet could have implications for fundamental differences between mammals and birds, such as in the physiology of sleep (Roth et al 2006, Lesku et al 2011. Assuming that most activity budgets of free-ranging animals are limited to daytime observations, this difference might also underlie the finding by Van Gils et al (2007) that foraging times in birds are longer than in mammals.…”

Section: Discussionmentioning

confidence: 99%

Comparative digesta retention patterns in ratites

Frei

Ortmann

Reutlinger³

et al. 2015

The Auk

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Ratites differ distinctively in the anatomy of their digestive tract. For example, Ostriches (Struthio camelus) have a particularly long, voluminous colon and long paired caeca, Rheas (Rhea spp.) are characterised by a short colon with particularly prominent paired caeca, and Emus (Dromaius novaehollandiae) -have neither very prominent caeca nor a prominent colon. We tested whether digesta excretion patterns corresponded to these differences in anatomy, expecting Ostriches to have the longest and Emus the shortest digesta retention times, and Rheas possibly showing a selective retention of fluids observed in other birds and mammals with prominent caeca. We used 6 Ostriches (97-123kg), 5 Greater Rheas (R. americana, 22-27kg) and 2 Emus (32-34kg) fed a common diet of alfalfa pellets ad libitum in captivity. Intake per unit of metabolic body mass did not differ between Ostriches and Rheas but was significantly higher in Emus, which also displayed higher defecation frequencies and lower fiber digestibility. Mean digesta retention time for small fiber particles (2 mm) differed significantly among species ; Emu: 1.3-1.8h), but there were no differences between the retention of 2 mm or 8 mm particles or a solute marker within species. The shape of the marker excretion curves corresponded to digesta mixing in the digestive tract of Ostriches and Rheas but not Emus. The calculated dry matter gut fill (% of body mass) was significantly higher in Ostriches (1.6-1.8) than Rheas (0.3-1.0) and Emus (0.2). Ostriches had the highest, and Emus the lowest fecal dry matter concentration. These physiological findings match the differences in digestive anatomy and support the concept that in ratites, herbivory -and hence flightlessness -evolved repeatedly in different ways. ABSTRACT Ratites differ distinctively in the anatomy of their digestive tracts. For example, Common Ostriches (Struthio camelus, hereafter Ostriches) have a particularly long, voluminous colon and long, paired caeca; Rheas (Rhea spp.) are characterized by a short colon with particularly prominent paired caeca; and Emus (Dromaius novaehollandiae) have neither prominent caeca nor a prominent colon. We tested whether digesta excretion patterns corresponded to these differences in anatomy, expecting Ostriches to have the longest and Emus the shortest digesta retention times, and Rheas possibly showing a selective retention of fluids observed in other birds and mammals with prominent caeca. We used 6 Ostriches (97-123 kg), 5 Greater Rheas (R. americana, 22-27 kg), and 2 Emus (32-34 kg) fed a common diet of alfalfa pellets ad libitum in captivity. Intake per unit of metabolic body mass did not differ between Ostriches and Greater Rheas but was significantly higher in Emus, which also displayed higher defecation frequencies and lower fiber digestibility. Mean digesta retention time for small fiber particles (2 mm) differed significantly among species (Ostrich: 30-36 h; Greater Rhea: 7-19 h; Emu: 1.3-1.8 h), but there were no differences between the retention o...

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“…Although the so-called mature form of MAS (viz., rapid eye movement (REM) or 'paradoxical' sleep [5][6][7] ) appears to have evolved independently in birds and mammals [2,8,9] , many ectothermic vertebrates are also on record as…”

Section: ·Review·mentioning

confidence: 99%

“…3). While not unexpected in view of their taxonomic proximity to the avian lineage [8,9] , it is interesting from an evolutionary point of view that a monotreme mammal, the duckbill platypus, can be seen in a recent …”

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confidence: 99%

Perchance to dream? Primordial motor activity patterns in vertebrates from fish to mammals: their prenatal origin, postnatal persistence during sleep, and pathological reemergence during REM sleep behavior disorder

Corner

Schenck

2015

Neurosci. Bull.

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An overview is presented of the literature dealing with sleep-like motility and concomitant neuronal activity patterns throughout the life cycle in vertebrates, ectothermic as well as endothermic. Spontaneous, periodically modulated, neurogenic bursts of non-purposive movements are a universal feature of larval and prenatal behavior, which in endothermic animals (i.e. birds and mammals) continue to occur periodically throughout life. Since the entire body musculature is involved in ever-shifting combinations, it is proposed that these spontaneously active periods be designated as 'rapid-BODY-movement' (RBM) sleep. The term 'rapid-EYEmovement (REM) sleep', characterized by attenuated muscle contractions and reduced tonus, can then be reserved for sleep at later stages of development. Mature stages of development in which sustained muscle atonia is combined with 'paradoxical arousal' of cortical neuronal firing patterns indisputably represent the evolutionarily most recent aspect of REM sleep, but more research with ectothermic vertebrates, such as fi sh, amphibians and reptiles, is needed before it can be concluded (as many prematurely have) that RBM is absent in these species. Evidence suggests a link between RBM sleep in early development and the clinical condition known as 'REM sleep behavior disorder (RBD)', which is characterized by the resurgence of periodic bouts of quasi-fetal motility that closely resemble RBM sleep. Early developmental neuromotor risk factors for RBD in humans also point to a relationship between RBM sleep and RBD.

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Ostriches Sleep like Platypuses

Cited by 86 publications

References 55 publications

Different Simultaneous Sleep States in the Hippocampus and Neocortex

Different Simultaneous Sleep States in the Hippocampus and Neocortex

Comparative digesta retention patterns in ratites

Perchance to dream? Primordial motor activity patterns in vertebrates from fish to mammals: their prenatal origin, postnatal persistence during sleep, and pathological reemergence during REM sleep behavior disorder

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