Analysis Of Cross-species Anatomical Connection Differences Between Human And Macaque Broca Region

Cross-species comparison of brain tissue has become an important way to explore the level of brain evolution.Because some anatomical and physiological studies that cannot be performed in the human brain can be carried out in the monkey brain,the macaque has been widely used to understand the human brain.The Broca district is mainly responsible for the processing of language information and the generation of utterances,and is closely related to the development of human language ability.Although from the anatomical point of view,the 44 and 45 regions of the macaque brain have been regarded as the homologous brain regions of the Broca region of the human brain,and the Broca45 homologous brain region of the macaque brain has been further subdivided into the rostral areas(45A)and caudal area(45B).However,it is uncertain whether there is a crossspecies consistency in the connection structure between the human Broca area and macaque Broca area,and it is also uncertain whether there is a similar subregional division of the broca45 subregion of the rhesus monkey in the human brain.In order to confirm whether the Broca region,which is anatomically homologous in human and macaque brains,has a cross-species consistency in the white matter fiber junction structure,and whether the human Broca45 subregion has a similar subregional division situation to the macaque Broca45 subregion.In this paper,non-invasive methods are used to describe the connection structure of brain regions using the number of white matter fiber bundles between different brain regions.By constructing the connectivity fingerprints of the Broca homologous brain regions of human brain and rhesus monkey brain,the cross-species connectivity difference analysis of Broca brain regions was carried out.This paper introduces a brain region segmentation method based on whole-brain probabilistic fiber tract tracking,realizes the subregion segmentation of Broca45 region of the human brain,and establishes a cross-species connectivity fingerprint between Broca45 homologous subregions.In the process of analyzing differences in cross-species connection structures,statistical methods such as permutation tests based on a large number of calculations(with a confidence of 90%)and independent sample ttests(with a confidence of 90%)were used to analyze human and macaque Broca.The differences in the connection structure of the homologous regions were analyzed based on a small sample.The research in this paper is supported by national fund projects and provincial R&D plans.The main research contents are as follows:(1)The region of interests were extracted from human brains and macaque brains.Aiming at the problem of differences in brain structures of different subjects,this article chooses to extract regions of interest at the individual level of subjects.This is because if the region of interest is extracted from the standard brain atlas,when it is registered on each subject's brain,there will be a certain deviation between different subjects,which will have an impact on subsequent experiments.Therefore,it is necessary to first register the entire standard brain atlas to individual brain regions,and then extract the region of interest.In the registration process,this paper uses linear registration to register the individual FA image to the individual T1 structure image,and linear plus nonlinear registration to register the individual T1 structure image to the standard space T1 structure image in a two-step registration method.And use the individual T1 structure image mask to generate the individual b0 image mask,which realizes the geometric distortion correction and artifact correction of the diffusion tensor imaging.(2)The connection patterns of the Broca subregions of the human brain and the macaque brain were compared.Aiming at the problem of small sample size and regional characteristics,this paper adopts permutation test based on small samples and independent sample t-test method to analyze the result value.First,the probabilistic fiber bundle tracking technology is used to track the Broca area of the human brain and the macaque brain,and establish a cross-species Broca area connectivity fingerprint.Then perform permutation tests and independent sample ttests on the fingerprints.Using the random arrangement of the samples,through a large number of calculations,the differences in the connectivity fingerprints of the Broca area of the human brain and the macaque brain are statistically analyzed at the overall level of the species.In addition,in the process of constructing connectivity fingerprints,a data processing method of mean normalization was used to reduce the impact of the magnitude difference between human brain and macaque white matter fiber bundles on cross-species comparison.(3)The connection patterns of Broca45 subregions of human brain and macaque brain were compared.Aiming at the problem that the Broca45 area of the human brain is not divided into sub-regions,this paper introduces a brain area segmentation method based on the whole brain probabilistic fiber tract tracking,which divides the Broca45 area of the human brain into two sub-regions.By comparing the results of the segmented subregions with the 45 A and 45 B subregions of the macaque brain,the segmentation results were marked,and new connectivity indicators were introduced to construct the connectivity fingerprints of the subregions,which were performed at the subregion level to analyze the differences in cross-species connection structure.