Study On Somatotopy Mapping Of Finger Based On Mri Compatibility Stimulation Technique

Brain function research is one of the most significant scientific challenges in human cognitive science.Moreover,it is also the core clinical basis of accurate diagnosis and treatment of encephalopathy.Tactile topological space mapping is one of the main direction of brain research.However,the pressure perception topology space mapping of fingers is difficult to distinguish the area between the phalanx,because the existing systems are not enough to stimulate targeted phalanx,thus lead to difficulty to evoke the corresponding brain activity.The purpose of this paper is to study the brain function space topology mapping features of pressure perception of phalanx by developing a new general functional magnetic resonance imaging(fMRI)compatible tactile stimulation system,which can produce controllable and accurate air flow.The system can be applied to activate different brain activity of knuckles in fMRI,and then we found the cross characteristics in the space mapping of forefinger and middle finger by fMRI experiments.First of all,according to the requirements ofMRI compatibility and experimental design indicators,this project designed tactile stimulation system,and place the controls and drives systems outside the MRI room.Then,combining the working principle and function requirement of tactile stimulation system,this project designed the architecture of stimulus regulator and completed overall architecture of software and hardware.Next,the system applied the STM32F103 to build the system core,and controlled pressure by the analog signal through the DAC8562 module,and realized the multi-channel output control through multi-channel control module.On the software design,this project formulated the overall process of software and completed the hierarchy system software design,including user interface layer and communication executing layer.Finally,we complete the physical prototype of the MRI compatibility finger stimulation system.Then,the system performance test and finger tactile sensing experiment were conducted.The system performance test includes the stimulation characteristic test and the MRI compatibility test.The test results show that the system is compatible with MRI and safe.The experimental study on finger tactile sensation includes the study of finger tactile sensation and fMRI experiment.Among them,the study of finger tactile perception is used to determine the frequency of the stimulation,and the fMRI experiment is used to study the experimental paradigm and to design space mapping experiment.In this project,7 subjects were recruited,and the experiment was performed in 3T fMRI using alternate block paradigm to present tactile stimuli in right index finger and middle finger.Finally,this article is based on Brain Voyager QX software to preprocesse the collected image data,including image format conversion and data filtering,slice timing,realignmen and coregister,image segmentation and normalise steps.Then we using the general linear model to handle the data through modeling analysis.The results showed that the primary sensory cortex(S1)effectively distinguished between the forefinger and middle finger fingertips and finger root corresponds to mapping area,thus obtained the spatial orientation map.Moreover,the index finger and middle finger showed space mapping properties,which has cross through each other.This study can solve the problem of brain function space mapping of finger-tactile sensation in theory,and provides the study of the tactile sensation of the brain.In the future,it can be applied not only to disease diagnosis and surgical planning,but also promoting the development of artificial intelligence based on tactile perception.