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Author Notes:

Corresponding author. Tel.: +1 404 727 2433; fax: +1 404 727 9873. shella.keilholz@bme.gatech.edu (S.D. Keilholz).

We thank the Laboratory of Functional and Molecular Imaging, National Institutes of Health, for allowing use of their 11.7-T MRI system.

Subject:

Keywords:

  • Science & Technology
  • Life Sciences & Biomedicine
  • Radiology, Nuclear Medicine & Medical Imaging
  • alpha-Chloralose
  • Medetomidine
  • Isoflurane
  • BOLD signal
  • fMRI
  • LOW-FREQUENCY FLUCTUATIONS
  • ECHO-PLANAR MRI
  • SOMATOSENSORY STIMULATION
  • NEURAL ACTIVITY
  • MOTOR CORTEX
  • BOLD SIGNALS
  • BRAIN
  • STATE
  • FMRI
  • OSCILLATIONS

Comparison of alpha-chloralose, medetomidine and isoflurane anesthesia for functional connectivity mapping in the rat

Tools:

Journal Title:

Magnetic Resonance Imaging

Volume:

Volume 28, Number 7

Publisher:

, Pages 995-1003

Type of Work:

Article | Post-print: After Peer Review

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 α-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 α-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.

Copyright information:

© 2010 Elsevier Inc.

This is an Open Access work distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (http://creativecommons.org/licenses/by-nc-nd/4.0/).

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