Title

Comparison of evoked cortical activity in conscious and propofol-anesthetized rats using functional MRI

UMMS Affiliation

Department of Psychiatry; Department of Radiology

Date

3-18-1999

Document Type

Article

Medical Subject Headings

*Anesthesia, General; Anesthetics, Intravenous; Animals; *Cerebrovascular Circulation; Consciousness; Electric Stimulation; *Evoked Potentials, Somatosensory; Hindlimb; *Magnetic Resonance Imaging; Male; Motor Cortex; Oxygen; Propofol; Rats; Rats, Sprague-Dawley; Somatosensory Cortex

Disciplines

Psychiatry

Abstract

Changes in cortical activity during foot shock were assessed under conscious and propofol-anesthetized conditions using functional magnetic resonance imaging (fMRI). Increases in signal intensity were observed in the contralateral somatosensory cortex in response to electrical shock of the hindpaw under both conditions. These increases in cortical signal ranged from 6% to 26% while awake and from 1% to 6% under propofol anesthesia. In each of the six animals studied, the largest increase in blood oxygenation level-dependent (BOLD)-based signal intensity was observed during consciousness. In three of six animals, propofol anesthesia depressed signal intensity by as much as 10-fold, showing that the level of cortical activity during foot shock is dampened by anesthesia. These results indicate it would be advantageous to use fully conscious animals to maximize BOLD-based MRI signal in certain behavioral studies using MR spectrometers with modest field strengths (1.0-2.0 T).

Rights and Permissions

Citation: Magn Reson Med. 1999 Feb;41(2):412-6.

Related Resources

Link to Article in PubMed

PubMed ID

10080292