Study Of Default Mode Network In Functional Magnetic Resonance Imaging Between Premature And Full-term Infants

BackgroundResting-state function magnetic resonance imaging(RS-fMRI) uses magnetic resonance imaging to detect the neuron activity which will lead to hemodynamic change, and is capable of detecting the spontaneous activity of the brain in resting state, which can provide more important information for physiological and pathological diagnosis in clinical practices. Its advantages like non-invasive, non-radiative and no need to conduct a mission is appropriate and beneficial for the study of neonates who are lack of recognition and mission awareness. As for the analysis and processing of the image data, through the application of amplitude of low-frequency fluctuation algorithm, the change of spontaneous activity level of the neonates’ brains in resting state can be calculated for further exploration of the different default mode network(DMN) between premature and full-term infant.Those neonates whose gestational age(GA) is under 37 weeks will be defined as a premature. Premature delivery is a very important topic for perinatology. Since part of the system of the premature is not well developed, which will cause many side effects, among which diseases like cerebral injury have the most complicated pathological mechanism that will make it very difficult for diagnosis and treatment in clinical practice. That is because, many of the mental diseases are thought to be closely related to the activity of the network, and it can be predicted that the brain structure and function of the premature and full-term infants are different, especially for the default mode network. The damage of default mode network for premature is mainly because of that premature delivery will significantly affect the early development of the brain and progressively affect the motor function, cognitive function and etc. Thus, it has increased the prevalence rate of infantile autism and attention deficit hyperactivity disorder. Moreover, some of the damages are unknown. Among all of the reported results, most of the school age children and adults who have shown related signs or symptoms have been studied by many researchers. However, there are much fewer reports regarding the study of premature.ObjectiveTo explore the difference and clinical value of the default mode network of premature and full-term infant through RS-fMRI and analysis of brain activity level via amplitude of low-frequency fluctuation algorithm.Method85 subjects including premature and full-term infants are selected in this study, and the data from 39 cases out of them has been excluded since the brain injury of some subjects is more significant and the following pre-treatment of the images is not standard, while the result of the 46 remaining neonates has been included in the following analysis. Among which, 17 subjects are from premature group and 29 subjects are from the full-term infant group. Compare the increase or decrease ALFF of different brain regions between premature and full-term infant by amplitude of low-frequency fluctuation algorithm.ResultThe RS-fMRI result indicated that the ALFF values of some brain regions were different between premature group and full-term infant group.Compared with full-term infants,the premature infants had significant decreases of ALFF in the anterior cingulate cortex(ACC),posterior cingulate cortex(PCC),middle cingulate cortex(MCC),medial prefrontal cortex(MPFC),inferior frontal gyrus(IFG),inferior orbitofrontal cortex,middle temporal lobe(MTL),anterior temporal lobe(ATL),pallidum,parahippocampal cortex(PHC),putamen,while the significant increases of ALFF in precuneus(PCu),calcarine cortex.ConclusionIn resting state, the premature infant group presented abnormal structure and function in some brain regions comparing to the full-term infant group, premature infant group has significantly decreased function and activity of brain region in frontal lobe,temporal lobe,ACC,PCC and so on, but some of the functions concentrating in visual regions have been enhanced, indicating that compensatory effect may exist in the brains of premature infants.It is worth noting that, the ALFF value has been decreased in MCC region for premature infant, which is closely related to human recognition process, indicating that premature delivery may affect self-awareness and delayed the development of self-awareness, also indicating that self-awareness appeared during neonatal period.