Unihemispheric slow wave sleep and the state of the eyes in a white whale

Lyamin, Oleg I.; Mukhametov, L. M.; Siegel, Jerome M.; Nazarenko, E. A.; Polyakova, I. N.; Шпак, О. В.

doi:10.1016/s0166-4328(01)00346-1

Cited by 102 publications

(68 citation statements)

References 10 publications

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“…This research was soon followed by two additional studies reaching the opposite conclusion (Gnone et al 2006;Sekiguchi et al 2006). Dolphins exhibit unihemispheric sleep, where slow-wave electroencephalogram (EEG) patterns restricted to a single hemisphere are linked to closure of the contralateral eye (Mukhametov 1987;Lyamin et al 2002Lyamin et al , 2004. Swimming and unihemispheric sleep are compatible: the underwater sleeping behavior termed "swim rest" is associated with continuous activity.…”

Section: The Dolphin Dilemmamentioning

confidence: 99%

Sleep and Development in Genetically Tractable Model Organisms

Kayser

Biron

2016

Genetics

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Sleep is widely recognized as essential, but without a clear singular function. Inadequate sleep impairs cognition, metabolism, immune function, and many other processes. Work in genetic model systems has greatly expanded our understanding of basic sleep neurobiology as well as introduced new concepts for why we sleep. Among these is an idea with its roots in human work nearly 50 years old: sleep in early life is crucial for normal brain maturation. Nearly all known species that sleep do so more while immature, and this increased sleep coincides with a period of exuberant synaptogenesis and massive neural circuit remodeling. Adequate sleep also appears critical for normal neurodevelopmental progression. This article describes recent findings regarding molecular and circuit mechanisms of sleep, with a focus on development and the insights garnered from models amenable to detailed genetic analyses.

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Section: The Dolphin Dilemmamentioning

confidence: 99%

Sleep and Development in Genetically Tractable Model Organisms

Kayser

Biron

2016

Genetics

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“…Dolphins and related small whales in the delphinoid cetacean family have shown slow wave sleep (SWS) electroencephalograms (EEG) in one brain hemisphere while producing waking EEG in the other (Serafetinides et al, 1970;Mukhametov et al, 1977;Mukhametov, 1984;Mukhametov, 1987;Ridgway, 2002;Lyamin et al, 2001;Lyamin et al, 2004). Left and right hemispheres alternate SWS by some unknown mechanism.…”

Section: Introductionmentioning

confidence: 99%

“…Several physiological and anatomical observations suggest a degree of dolphin brain hemispheric independence. These observations include independent eye movement and closure (McCormick, 1969;Dawson et al, 1981;Lyamin et al, 2001;Lyamin et al, 2004), observations of behavior in nocturnal rest periods (Flanigan, Jr, 1974;Goley, 1999), a small corpus callosum , complete crossing of the nerves at the optic chiasm , and absence of an arterial Circle of Willis (McFarland et al, 1979). What triggers one hemisphere to go into SWS while the other hemisphere often displays an EEG indistinguishable from that of an awake animal remains to be determined.…”

Section: Introductionmentioning

confidence: 99%

Functional imaging of dolphin brain metabolism and blood flow

Ridgway

Houser

Finneran

et al. 2006

Journal of Experimental Biology

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SUMMARY This report documents the first use of magnetic resonance images (MRIs) of living dolphins to register functional brain scans, allowing for the exploration of potential mechanisms of unihemispheric sleep. Diazepam has been shown to induce unihemispheric slow waves (USW), therefore we used functional imaging of dolphins with and without diazepam to observe hemispheric differences in brain metabolism and blood flow. MRIs were used to register functional brain scans with single photon emission computed tomography (SPECT)and positron emission tomography (PET) in trained dolphins. Scans using SPECT revealed unihemispheric blood flow reduction following diazepam doses greater than 0.55 mg kg-1 for these 180-200 kg animals. Scans using PET revealed hemispheric differences in brain glucose consumption when scans with and without diazepam were compared. The findings suggest that unihemispheric reduction in blood flow and glucose metabolism in the hemisphere showing USW are important features of unihemispheric sleep. Functional scans may also help to elucidate the degree of hemispheric laterality of sensory and motor systems as well as in neurotransmitter or molecular mechanisms of unihemispheric sleep in delphinoid cetaceans. The findings also demonstrate the potential value of functional scans to explore other aspects of dolphin brain physiology as well as pathology.

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“…Left and right hemispheres alternate between SWS and waking by some still unknown mechanism. Independent eye movement and closure (McCormick, 1969;Dawson et al, 1981;Lyamin et al, 2001), observations of behavior in nocturnal rest periods (Flanigan, 1974;Goley, 1999), a small corpus callosum , complete crossing of the nerves at the optic chiasm and absence of an arterial Circle of Willis (McFarland et al, 1979) all suggest a degree of hemispheric independence. No studies, however, have demonstrated a physiological or behavioral advantage to 'uni-hemispheric sleep' or documented long-term vigilance in dolphins.…”

Section: Introductionmentioning

confidence: 99%