The Fmri-based Brain Function Detection

Research on human brain function has been one of the most challenging tasks for a long time. Since the 1990s, brain functional imaging techniques are widely applied and extensively developed. Functional magnetic resonance imaging (fMRI) holds a very important station in brain functional study because of its non-invasive, repeat, high spatial resolution. According to different experiment aims and changing experiment conditions, we can measure many physiology and biophysics parameters by functional magnetic resonance imaging techniques, and then we gain quite abundant data set. Functional brain imaging has a revolutionized role in the improvement of scientific and cognitive science research. In this study, functional magnetic resonance techniques was introduced in quantitative analysis of asymmetry BOLD( blood oxygenation-level dependent, BOLD) hemodynamic response in motor cortex in the healthy young and elderly and detectiong the brain activity during reward-based decision-making under uncertain contexture.In the research on the effect of quantitative analysis of asymmetry BOLD hemodynamic response in motor cortex, a weighted z value Z w, which is a new index, the statistical z value weighted by the number of active voxels, was introduced to more accurately measure BOLD signal change between left and right motor areas, and to investigate whether there are significant age-related changes in the pattern of cortical activation during simple repetitive movements. Result of single-subject analysis showed that the Z w of BOLD signal percent change in right motor area is higher than that in left motor area in each group. In group analysis, the result indicated that the degree of cortical asymmetry change with age difference. These findings suggest that there are significant age-related differences in the activation pattern associated with repetitive movements.In the research on reward-based modality decision-making behavior under uncertain contexture, fMRI was introduced in our experiment, which was designed on the basis of previous experiment,excluding other no-related factors . So the experiment explored in this paper has more accurately detected the reward-related regions and the regions which are responsible for expressing the modality of reward. The analysis of beavior data showed that the reactive time from subject's correct reaction was statistically different with that from subject's wrong reaction. The correct reactive time is obviously shorter than the wrong reactive time.The results from the analysis of fMRI data have showed that the actived intensity of striatum under the condition of increasing reward than that under the condition of reduction reward. These results were consistant with results from previous research, which suggested that the degree of activation of the striatum varied consistently with both the magnitude and valence of the reward, played a role of reward presentation. In addition, in the case of different degrees of reward, the amygdala activity level is different.the left amygdala was more activated when win in the selection and the right amygdala was more activated when loss in the selection. This mechanism is thought to improve choices over time, by continually updating the outcomes according to the rewards and punishments encountered in the environment.The results of this study reveal that there is indeed such a mechanism responsible for receive information of reward, and each part in this nervous system has their specific role in the process of decision-making. The striatum, amygdala will be responsible for receiving the reward information from outside world and tansform them into the expression of neuro, which could be recognized by nervous system.