title: Comparison of alpha-chloralose, medetomidine and isoflurane anesthesia for functional connectivity mapping in the rat.
abstract: Functional connectivity measures based upon low-frequency blood-oxygenation-level-dependent functional magnetic resonance imaging (BOLD fMRI) signal fluctuations have become a widely used tool for investigating spontaneous brain activity in humans. Still unknown, however, is the precise relationship between neural activity, the hemodynamic response and fluctuations in the MRI signal. Recent work from several groups had shown that correlated low-frequency fluctuations in the BOLD signal can be detected in the anesthetized rat - a first step toward elucidating this relationship. Building on this preliminary work, through this study, we demonstrate that functional connectivity observed in the rat depends strongly on the type of anesthesia used. Power spectra of spontaneous fluctuations and the cross-correlation-based connectivity maps from rats anesthetized with alpha-chloralose, medetomidine or isoflurane are presented using a high-temporal-resolution imaging sequence that ensures minimal contamination from physiological noise. The results show less localized correlation in rats anesthetized with isoflurane as compared with rats anesthetized with alpha-chloralose or medetomidine. These experiments highlight the utility of using different types of anesthesia to explore the fundamental physiological relationships of the BOLD signal and suggest that the mechanisms contributing to functional connectivity involve a complicated relationship between changes in neural activity, neurovascular coupling and vascular reactivity.
authors.affiliation: Department of Radiology, Center for Biomedical Imaging, New York University School of Medicine, New York, NY 10012, USA.
authors.forename: Kathleen A
authors.initials: KA
authors.lastname: Williams
authors.forename: Matthew
authors.initials: M
authors.lastname: Magnuson
authors.forename: Waqas
authors.initials: W
authors.lastname: Majeed
authors.forename: Stephen M
authors.initials: SM
authors.lastname: LaConte
authors.forename: Scott J
authors.initials: SJ
authors.lastname: Peltier
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Hu
authors.forename: Shella D
authors.initials: SD
authors.lastname: Keilholz
mesh_terms: D000777:Anesthetics / Q000008:administration & dosage; D000818:Animals; D001921:Brain / Q000187:drug effects* / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods*; D002698:Chloralose / Q000008:administration & dosage*; D007530:Isoflurane / Q000008:administration & dosage*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D020926:Medetomidine / Q000008:administration & dosage*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D000777:Anesthetics; D002698:Chloralose; D007530:Isoflurane; D020926:Medetomidine
references.citation: Neuroimage. 2006 Jul 15;31(4):1536-48
references.pmid: 16632379
references.citation: Magn Reson Med. 2006 Feb;55(2):316-24
references.pmid: 16372281
references.citation: Proc Natl Acad Sci U S A. 1998 Dec 22;95(26):15741-6
references.pmid: 9861040
references.citation: Proc Natl Acad Sci U S A. 2007 Nov 20;104(47):18760-5
references.pmid: 18003904
references.citation: Neuroimage. 2006 Feb 15;29(4):1303-10
references.pmid: 16223588
references.citation: Neuroimage. 2008 Jan 15;39(2):775-85
references.pmid: 17964186
references.citation: J Neurosci. 2009 Aug 5;29(31):9850-60
references.pmid: 19657037
references.citation: Neuroimage. 2002 Aug;16(4):985-92
references.pmid: 12202086
references.citation: Neuroimage. 2005 Jan 1;24(1):92-100
references.pmid: 15588600
references.citation: Hum Brain Mapp. 2008 Nov;29(11):1265-75
references.pmid: 17894392
references.citation: Neuroimage. 2006 Jul 15;31(4):1592-600
references.pmid: 16549367
references.citation: J Cereb Blood Flow Metab. 1997 Mar;17(3):301-8
references.pmid: 9119903
references.citation: Proc Natl Acad Sci U S A. 2002 Nov 12;99(23):15182-7
references.pmid: 12407177
references.citation: Proc Natl Acad Sci U S A. 2007 Nov 13;104(46):18265-9
references.pmid: 17991778
references.citation: AJNR Am J Neuroradiol. 2001 Aug;22(7):1326-33
references.pmid: 11498421
references.citation: Neuroreport. 2005 Feb 28;16(3):285-8
references.pmid: 15706237
references.citation: Magn Reson Med. 1995 Aug;34(2):201-12
references.pmid: 7476079
references.citation: Proc Natl Acad Sci U S A. 2007 Dec 18;104(51):20546-51
references.pmid: 18079290
references.citation: Neuroimage. 2008 Jul 1;41(3):1168-76
references.pmid: 18434203
references.citation: Brain Res. 1997 Nov 14;775(1-2):233-9
references.pmid: 9439851
references.citation: Magn Reson Med. 2000 Jul;44(1):162-7
references.pmid: 10893535
references.citation: Magn Reson Med. 1995 Oct;34(4):537-41
references.pmid: 8524021
references.citation: Comput Biomed Res. 1996 Jun;29(3):162-73
references.pmid: 8812068
references.citation: Magn Reson Med. 1999 Mar;41(3):469-73
references.pmid: 10204868
references.citation: Neuroimage. 2008 May 1;40(4):1738-47
references.pmid: 18339559
references.citation: Hum Brain Mapp. 2007 Oct;28(10):967-78
references.pmid: 17133390
references.citation: Magn Reson Med. 2008 May;59(5):1021-9
references.pmid: 18429028
references.citation: Cereb Cortex. 2007 Apr;17(4):942-50
references.pmid: 16731882
references.citation: J Magn Reson Imaging. 2009 Aug;30(2):384-93
references.pmid: 19629982
references.citation: Vet Anaesth Analg. 2009 Jul;36(4):319-27
references.pmid: 19470142
references.citation: Neuroimage. 2008 Jan 1;39(1):248-60
references.pmid: 17904868
references.citation: Nature. 2001 Jul 12;412(6843):150-7
references.pmid: 11449264
references.citation: Brain Res. 2008 Jan 29;1191:157-67
references.pmid: 18096143
references.citation: Magn Reson Med. 2004 Jul;52(1):89-99
references.pmid: 15236371
references.citation: Neuroimage. 1996 Dec;4(3 Pt 1):183-93
references.pmid: 9345508
references.citation: NMR Biomed. 1997 Jun-Aug;10(4-5):165-70
references.pmid: 9430343
references.citation: Magn Reson Imaging. 2005 May;23(4):531-7
references.pmid: 15919598
references.citation: AJNR Am J Neuroradiol. 2000 Oct;21(9):1636-44
references.pmid: 11039342
references.citation: Am J Physiol. 1988 Jan;254(1 Pt 2):H28-33
references.pmid: 3337256