title: FDG-PET analysis of amygdalar-cortical network covariance during pre- versus post-menopausal estrogen levels: potential relevance to resting state networks, mood, and cognition.
abstract: OBJECTIVE
  1.) Expand the scope of neuroendocrine applications of functional neuroimaging techniques. 2.) Compare the covariance of amygdalar activity with that of the rest of the brain during pre- and post-menopausal levels of estrogen (E2). Based on the distribution of cortical E2 receptors and the neocortical regions where E2 has been shown to preferentially accumulate, we predict that E2 infusion will increase covariance of amygdalar activity with that of the temporal and frontal cortices.
  
  
  METHODS
  This basic physiology study employed a within-subject design. All participants were post-menopausal women (n =7). Analysis of covariance between whole brain and amygdalar regional cerebral glucose consumption (CMRglc) was conducted in a voxel-wise manner by means of the basic regression option in SPM2 and was applied to FDG-PET scans acquired at baseline and after a 24 hour graded E2 infusion.
  
  
  METHODS
  An academic medical center; Massachusetts General Hospital, Boston, Massachusetts.
  
  
  RESULTS
  E2 levels (mean +/- sem) were significantly greater at 24 hours (257.9 pg/mL +/- 29.7) than at 0 hours (28.1 pg/mL +/- 3.4). Right amygdalar CMRglc showed a significant covariance with activity of three different regions of the temporal cortex during E2 infusion, but none at baseline. In addition, right amygdalar CMRglc covaried with that of the right medial and superior frontal gyri only during E2 infusion.
  
  
  CONCLUSIONS
  In addition to suggesting changes in amygdalar-cortical network connectivity as a result of short-term E2 exposure, these analyses provide evidence that basic neuroendocrine research may benefit from further use of FDG-PET and other functional neuroimaging modalities for network level analyses.
authors.affiliation: Graduate School of Arts and Sciences, Department of Statistics, Columbia University, New York, NY 10027, USA. weo2101@columbia.edu
authors.forename: William E
authors.initials: WE
authors.lastname: Ottowitz
authors.forename: David
authors.initials: D
authors.lastname: Derro
authors.forename: Darin D
authors.initials: DD
authors.lastname: Dougherty
authors.forename: Martin A
authors.initials: MA
authors.lastname: Lindquist
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Fischman
authors.forename: Janet E
authors.initials: JE
authors.lastname: Hall