Comparison of evoked cortical activity in conscious and propofol-anesthetized rats using functional MRI
Department of Psychiatry; Department of Radiology
*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
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).
Magn Reson Med. 1999 Feb;41(2):412-6.
Magnetic resonance in medicine : official journal of the Society of Magnetic Resonance in Medicine / Society of Magnetic Resonance in Medicine
Lahti, Katariina M.; Ferris, Craig F.; Li, Fuhai; Sotak, Christopher H.; and King, Jean A., "Comparison of evoked cortical activity in conscious and propofol-anesthetized rats using functional MRI" (1999). Psychiatry Publications and Presentations. 340.