title: Functional connectivity MR imaging reveals cortical functional connectivity in the developing brain.
abstract: OBJECTIVE
  Unlike conventional functional MR imaging where external sensory/cognitive paradigms are needed to specifically activate different regions of the brain, resting functional connectivity MR imaging acquires images in the absence of cognitive demands (a resting condition) and detects brain regions, which are highly temporally correlated. Therefore, resting functional MR imaging is highly suited for the study of brain functional development in pediatric subjects. This study aimed to determine the temporal and spatial patterns of rfc in healthy pediatric subjects between 2 weeks and 2 years of age.
  
  
  METHODS
  Rfc studies were performed on 85 children: 38 neonates (2-4 weeks of age), 26 one-year-olds, and 21 two-year-olds. All subjects were imaged while asleep; no sedation was used. Six regions of interest were chosen, including the primary motor, sensory, and visual cortices in each hemisphere. Mean signal intensity of each region of interest was used to perform correlation analysis pixel by pixel throughout the entire brain, identifying regions with high temporal correlation.
  
  
  RESULTS
  Functional connectivity was observed in all subjects in the sensorimotor and visual areas. The percent brain volume exhibiting rfc and the strength of rfc continued to increase from 2 weeks to 2 years. The growth trajectories of the percent brain volume of rfc appeared to differ between the sensorimotor and visual areas, whereas the z-score was similar. The percent brain volume of rfc in the sensorimotor area was significantly larger than that in the visual area for subjects 2 weeks of age (P = .008) and 1-year-olds (P = .017) but not for the 2-year-olds.
  
  
  CONCLUSIONS
  These findings suggest that rfc in the sensorimotor precedes that in the visual area from 2 weeks to 1 year but becomes comparable at 2 years. In contrast, the comparable z-score values between the sensorimotor and visual areas for all age groups suggest a disassociation between percent brain volume and the strength of cortical rfc.
authors.affiliation: Department of Radiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA. weili_lin@med.unc.edu
authors.forename: W
authors.initials: W
authors.lastname: Lin
authors.forename: Q
authors.initials: Q
authors.lastname: Zhu
authors.forename: W
authors.initials: W
authors.lastname: Gao
authors.forename: Y
authors.initials: Y
authors.lastname: Chen
authors.forename: C-H
authors.initials: CH
authors.lastname: Toh
authors.forename: M
authors.initials: M
authors.lastname: Styner
authors.forename: G
authors.initials: G
authors.lastname: Gerig
authors.forename: J K
authors.initials: JK
authors.lastname: Smith
authors.forename: B
authors.initials: B
authors.lastname: Biswal
authors.forename: J H
authors.initials: JH
authors.lastname: Gilmore
mesh_terms: D000375:Aging / Q000473:pathology* / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods*; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D007223:Infant; D007231:Infant, Newborn; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D013003:Somatosensory Cortex / Q000033:anatomy & histology* / Q000502:physiology*; D014793:Visual Cortex / Q000033:anatomy & histology* / Q000502:physiology*
references.citation: Neuroimage. 2002 Aug;16(4):985-92
references.pmid: 12202086
references.citation: J Cereb Blood Flow Metab. 1997 Mar;17(3):301-8
references.pmid: 9119903
references.citation: Neuropediatrics. 1991 May;22(2):85-91
references.pmid: 1857499
references.citation: Neuroimage. 2007 Mar;35(1):308-25
references.pmid: 17239623
references.citation: Neuroimage. 2006 Mar;30(1):184-202
references.pmid: 16376577
references.citation: Hum Brain Mapp. 2008 Jun;29(6):671-82
references.pmid: 17598166
references.citation: Neuroimage. 2003 Aug;19(4):1463-76
references.pmid: 12948703
references.citation: Neuroimage. 1998 Feb;7(2):119-32
references.pmid: 9558644
references.citation: Hum Brain Mapp. 2007 Oct;28(10):967-78
references.pmid: 17133390
references.citation: Neuroreport. 2002 Dec 20;13(18):2487-92
references.pmid: 12499854
references.citation: Neuroimage. 2000 Nov;12(5):582-7
references.pmid: 11034865
references.citation: Neuroreport. 2006 Feb 6;17(2):209-13
references.pmid: 16407773
references.citation: J Comput Assist Tomogr. 1998 Jan-Feb;22(1):139-52
references.pmid: 9448779
references.citation: Top Magn Reson Imaging. 2004 Jun;15(3):129-58
references.pmid: 15479997
references.citation: Cereb Cortex. 2003 Apr;13(4):422-33
references.pmid: 12631571
references.citation: Neuroimage. 2003 Sep;20(1):145-58
references.pmid: 14527577
references.citation: Neuroimage. 2007 Mar;35(1):396-405
references.pmid: 17239622
references.citation: Neuropediatrics. 2000 Feb;31(1):24-32
references.pmid: 10774992
references.citation: Proc Natl Acad Sci U S A. 2007 Sep 25;104(39):15531-6
references.pmid: 17878310
references.citation: J Comput Assist Tomogr. 1998 Jan-Feb;22(1):153-65
references.pmid: 9448780
references.citation: Magn Reson Imaging. 2005 Jan;23(1):41-6
references.pmid: 15733787
references.citation: Biol Psychiatry. 2007 Sep 1;62(5):429-37
references.pmid: 17210143
references.citation: Ann Neurol. 1987 Oct;22(4):487-97
references.pmid: 3501693
references.citation: Philos Trans R Soc Lond B Biol Sci. 2005 May 29;360(1457):1001-13
references.pmid: 16087444
references.citation: J Neurosci. 2007 Feb 7;27(6):1255-60
references.pmid: 17287499
references.citation: Magn Reson Med. 2001 Sep;46(3):628-9
references.pmid: 11550260
references.citation: Neurosci Lett. 2006 May 29;400(1-2):39-43
references.pmid: 16510242
references.citation: Magn Reson Med. 2001 Apr;45(4):635-44
references.pmid: 11283992
references.citation: Neuroimage. 2004 Apr;21(4):1652-64
references.pmid: 15050588
references.citation: Magn Reson Imaging. 2007 Jan;25(1):47-56
references.pmid: 17222714
references.citation: Magn Reson Imaging. 2002 Feb;20(2):199-205
references.pmid: 12034341
references.citation: Proc Natl Acad Sci U S A. 2003 Jan 7;100(1):253-8
references.pmid: 12506194
references.citation: Neuroimage. 2002 Nov;17(3):1325-35
references.pmid: 12414272
references.citation: NMR Biomed. 1997 Jun-Aug;10(4-5):165-70
references.pmid: 9430343
references.citation: Neuroreport. 2006 Nov 6;17(16):1687-90
references.pmid: 17047454
references.citation: AJNR Am J Neuroradiol. 2000 Oct;21(9):1636-44
references.pmid: 11039342
references.citation: Magn Reson Imaging Clin N Am. 1999 May;7(2):237-54, vii-viii
references.pmid: 10382159