Observations of Oxygen Administration Effects on Visuospatial Cognitive Performance using Time Course Data Analysis of fMRI

ABSTRACT

PURPOSE: This study attempted to investigate the effects of supply of highly concentrated (30%) oxygen on human ability of visuospatial cognition using time course data analysis of functional Magnetic Resonance Imaging (fMRI). MATERIALS AND METHODS: To select an item set in the visuospatial performance test, two questionnaires with similar difficulty were developed through group testing. A group test was administered to 263 college students. Two types of questionnaire containing 20 questions were developed to measure the ability of visuospatial cognition. Eight college students (right-handed male, average age of 23.5 yrs) were examined for fMRI study. The experiment consisted of two runs of the visuospatial cognition testing, one with 21% level of oxygen and the other with 30% oxygen level. Each run consisted of 4 blocks, each containing control and visuospatial items. Functional brain images were taken from 3T MRI using the single-shot EPI method. Using the subtraction procedure, activated areas in the brain during visuospatial tasks were col-orcoded by t-score. To investigate the time course data in each activated area from brain images, 4 typical regions (cerebellum, occipital lobe, parietal lobe, and frontal lobe) were selected. RESULTS: The average accuracy was 50.63 +/-8.63 and 62.50 +/-9.64 for 21% and 30% oxygen respectively, and a statistically significant difference was found in the accuracy between the two types of oxygen (p<0.05). There were more activation areas observed at the cerebellum, occipital lobe, parietal lobe and frontal lobe with 30% oxygen administration. The rate of increase in the cerebellum, occipital lobe and parietal lobe was 17% and that of the frontal lobe, 50%. Especially, there were increase of intensity of BOLD signal at the parietal lobe with 30% oxygen administration. The increase rate of the left parietal lobe was 1.4% and that of the right parietal lobe, 1.7%. CONCLUSION: It is concluded that while performing visuospatial tasks, high concentrations of oxygen administration make oxygen administration sufficient, thus making neural network activate more, and the ability to perform visuospatial tasks increase.