Cortical Acetylcholine Release Is Lateralized during Asymmetrical Slow-Wave Sleep in Northern Fur Seals

• DOI: 10.1523/jneurosci.2968-07.2007
• Publication Date: 2007-10-31T16:28:22Z
• Authors: Jennifer L. Lapierre; Peter O. Kosenko; Oleg I. Lyamin; Tohru Kodama; Lev M. Mukhametov; Jerome M. Siegel
• Keywords: Microdialysis; Sleep

Fur seals are unique in that they display both bilateral slow-wave sleep (BSWS), as seen all terrestrial mammals, and with interhemispheric electroencephalogram (EEG) asymmetry, resembling the unihemispheric slow waves of cetaceans. Little is known about underlying mechanisms this phenomenon, which also termed asymmetrical wave (ASWS). However, we may begin to understand expression ASWS by studying neurotransmitter systems thought be involved generation maintenance sleep–wake states mammals. We examined bilaterally release cortical acetylcholine (ACh), a implicated regulation EEG behavioral arousal, across cycle four juvenile northern fur ( Callorhinus ursinus ). In vivo microdialysis high-performance liquid chromatography coupled electrochemical detection were used measure ACh levels during polygraphically defined states. Cortical was state-dependent, showing maximal active waking (AW), similar quiet (QW), rapid eye movement (REM) sleep, minimal BSWS. When compared BSWS, increased ∼300% AW, ∼200% QW REM sleep. During these symmetrical states, synchronously released from hemispheres. ASWS, lateralized greater hemisphere displaying lower voltage activity, at approximating those QW. These findings demonstrate tightly linked hemispheric activation.