Propofol attenuates responses of the auditory cortex to acoustic stimulation in a dose-dependent manner: a FMRI study.
BACKGROUND
Functional magnetic resonance imaging (fMRI) using blood-oxygen-level-dependent (BOLD) contrasts is a common method for studying sensory or cognitive brain functions. The aim of the present study was to assess the effect of the intravenous anaesthetic propofol on auditory-induced brain activation using BOLD contrast fMRI.


METHODS
In eight neurosurgical patients, musical stimuli were presented binaurally in a block design. Imaging was performed under five conditions: no propofol (or wakefulness) and propofol plasma target concentrations of 0.5, 1.0, 1.5, and 2.0 microg ml(-1).


RESULTS
During wakefulness we found activations in the superior temporal gyrus (STG) corresponding to the primary and secondary auditory cortex as well as in regions of higher functions of auditory information processing. The BOLD response decreased with increasing concentrations of propofol but remained partially preserved in areas of basic auditory processing in the STG during propofol 2.0 microg ml(-1).


CONCLUSIONS
Our results suggest a dose-dependent impairment of central processing of auditory information after propofol administration. These results are consistent with electrophysiological findings measuring neuronal activity directly, thus suggesting a dose-dependent impairment of central processing of auditory information after propofol administration. However, propofol did not totally blunt primary cortical responses to acoustic stimulation, indicating that patients may process auditory information under general anaesthesia.
Dueck
M H
MH
Department of Anaesthesiology, University of Cologne, Cologne, Germany. M.Dueck@uni-koeln.de
Petzke
F
F
Gerbershagen
H J
HJ
Paul
M
M
Hesselmann
V
V
Girnus
R
R
Krug
B
B
Sorger
B
B
Goebel
R
R
Lehrke
R
R
Sturm
V
V
Boerner
U
U
D000161:Acoustic Stimulation; D000328:Adult; D000768:Anesthesia, General; D000771:Anesthesia, Intravenous; D018686:Anesthetics, Intravenous / Q000097:blood; D001303:Auditory Cortex / Q000187:drug effects*; D001932:Brain Neoplasms / Q000601:surgery; D003627:Data Interpretation, Statistical; D004305:Dose-Response Relationship, Drug; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006439:Hemodynamics; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures; D010100:Oxygen / Q000097:blood; D015742:Propofol / Q000097:blood
D018686:Anesthetics, Intravenous; D010100:Oxygen; D015742:Propofol