title: Effects of hyperoxia on human sensorimotor cortex activity produced by electrical stimulation of the median nerve: a functional magnetic resonance imaging study.
abstract: This study investigated the effect of hyperoxia on sensorimotorcortical activity resulting from electrical stimulation of the median nerve, using functional magnetic resonance imaging (fMRI). Nine volunteers underwent stimulation at 5 and 100 Hz while breathing 21% FIO(2) (fraction of inspired oxygen) or 100% FIO(2). fMRI data were correlated with a stimulus predictor curve, transformed into Talairach space and averaged by group. Normoxic (21% FIO(2)) and hyperoxic (100% FIO(2)) sensorimotor activation volumes were compared using Student's t-test. There were no significant differences between the primary somatosensory/primary motor/Brodmann area 40 (SI/MI/Ba40) and secondary somatosensory cortex (SII) activation volumes for normoxia and hyperoxia. (P>0.05). There was no difference between SI/MI/Ba40 and SII activations at 5 and 100 Hz. In contrast to results previously reported for primary visual cortex (V1), hyperoxia did not enhance sensorimotor cortical activation in area SI/MI/Ba40 or SII. These results indicate that there is regional heterogeneity of the fMRI response to hyperoxia in the cerebral cortex.
authors.affiliation: Department of Neurosurgery, SUNY Upstate Medical University, 750 East Adams Street, Syracuse, NY 13210, USA. boakyem@netscape.net
authors.forename: Maxwell
authors.initials: M
authors.lastname: Boakye
authors.forename: Beth R
authors.initials: BR
authors.lastname: Krauss
authors.forename: Sean C
authors.initials: SC
authors.lastname: Huckins
authors.forename: Lin
authors.initials: L
authors.lastname: Zhang
authors.forename: Nikolaus M
authors.initials: NM
authors.lastname: Szeverenyi
authors.forename: Charles J
authors.initials: CJ
authors.lastname: Hodge
mesh_terms: D000328:Adult; D000344:Afferent Pathways / Q000502:physiology*; D001931:Brain Mapping; D004558:Electric Stimulation; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D018496:Hyperoxia / Q000503:physiopathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008475:Median Nerve / Q000502:physiology*; D008875:Middle Aged; D009431:Neural Conduction / Q000502:physiology*; D013003:Somatosensory Cortex / Q000502:physiology*