Journal article
The microstructure of active and quiet sleep as cortical delta activity emerges in infant rats
Sleep (New York, N.Y.), Vol.31(5), pp.691-699
05/2008
DOI: 10.1093/sleep/31.5.691
PMCID: PMC2398759
PMID: 18517038
Abstract
Previous investigators have suggested that quiet sleep (QS) in rats develops rapidly upon the emergence of cortical delta activity around postnatal day (P)11 and that the presence of "half-activated" active sleep (AS) suggests that infant sleep is initially disorganized. To address these issues, we examined the temporal organization of sleep states during the second postnatal week in rats as delta activity emerges.
Subjects were P9, P11, and P13 Sprague-Dawley rats. Electroencephalogram and nuchal electromyogram electrodes were implanted, and data were recorded at thermoneutrality for 2 hours.
At all ages, using electromyogram and behavioral criteria, QS (defined as nuchal atonia and behavioral quiescence) dominated the first third of each sleep period, whereas AS (defined as nuchal atonia accompanied by myoclonic twitching) dominated the last third. When delta activity, which was first detected at P11, could be added to the definition of QS, gross assessments of sleep-state organization were not altered, although it was now possible to identify brief periods of QS interposed between periods of AS. No evidence of "half-activated" AS was found. Finally, "slow activity transients" were detected and were primarily associated with QS; their rate of occurrence declined as delta activity emerged.
When delta activity emerges at P11, it integrates smoothly with periods of QS, as defined using electromyogram and behavioral criteria alone. Delta activity helps to refine estimates of QS duration but does not reflect a significant alteration of sleep-state organization. Rather, this organization is expressed much earlier in ontogeny as fluctuations in muscle tone and associated phasic motor activity.
Details
- Title: Subtitle
- The microstructure of active and quiet sleep as cortical delta activity emerges in infant rats
- Creators
- Adele M H Seelke - Department of Psychology, University of Iowa, Iowa City, Iowa 52242, USAMark S Blumberg
- Resource Type
- Journal article
- Publication Details
- Sleep (New York, N.Y.), Vol.31(5), pp.691-699
- DOI
- 10.1093/sleep/31.5.691
- PMID
- 18517038
- PMCID
- PMC2398759
- NLM abbreviation
- Sleep
- ISSN
- 0161-8105
- eISSN
- 1550-9109
- Publisher
- United States
- Grant note
- MH50701 / NIMH NIH HHS R01 MH050701 / NIMH NIH HHS MH66424 / NIMH NIH HHS K02 MH066424 / NIMH NIH HHS R29 MH050701 / NIMH NIH HHS
- Language
- English
- Date published
- 05/2008
- Academic Unit
- Psychological and Brain Sciences; Iowa Neuroscience Institute; Biology
- Record Identifier
- 9984002499702771
Metrics
32 Record Views