| Background With the quickening of the aging process, the incidence of cognitivedysfunction increase constantly in elderly people along with the increasing risk ofprogression to mild cognitive impairment (MCI) and dementia. Given the public healthimpact of MCI and Alzheimer’s disease (AD), cognitive dysfunction and its relateddiseases have received extensive attention.White matter lesions (WMLs) refer to abnormal periventricular or subcorticalsignal, which are often shown as hypodense signal on CT or hyperintense signal onT2-MRI. With the development and popularization of neuroimaging technology, it isbelieved that WMLs are a common imaging change in old people and its prevalencemay increase with aging. It has been widely confirmed that there is a close associationbetween WMLs and cognitive decline, and emerging data suggested that WMLs mightbe a potential imaging biomarker of the progression of MCI and AD.There was little research about WMLs in early stage because early clinicalperformance of WMLs is imperceptible due to its insidious onset, and people usuallyseek treatment with significant cognitive dysfunction in moderate and even severeWMLs. Furthermore, mild WMLs are little concurrent with other pathological changessuch as stroke and dementia compared to severe WMLs, so studying it can excludeother confounding brain injuries secondary to WMLs. Therefore, exploring thestructural and cognitive changes of mild WMLs it is beneficial for better understandingthe underlying pathogenesis of WMLs, and prevention of the progression of WMLsrelated diseases.Objective Applying multimodal neuroimaging methods to investigate the injurypatterns of brain gray/white structure, and resting brain functional activity of mildWMLs patients, and their relationship with cognitive abnormalities. Providinginformation on the characteristics and mechanisms of mild WMLs related cognitive declines.Methods The participants in the present study were from the Beijing Ageing BrainRejuvenation Initiative (BABRI).51subjects with mild WMLs and49controlparticipants completed serial neuropsychological tests. And underwent a3-T MRI scanthat included DTI, a rs-MRI using voxel-based morphometry (VBM) to detect thestructural change of gray and white matter, respectively. Additionally, amplitude of lowfrequency fluctuation (ALFF) of rs-fMRI has been used to investigate brain functionalactivity. Lastly, we analyzed the correlation among the structure of gray/white matter,brain functional activity and cognitive function.Results We found that:1) declines in cognitive functions such as global function,executive function and episodic memory in mild WMLs subjects;2) the white matterinjuries in the mild WMLs subjects were mainly in the fibers that projected to frontalareas, while gray matter structures were relatively intact;3) the overall resting-statefunction of the frontal area was significantly increased;4) the integrity of the neuralfibers in the inferior fronto-occipital fasciculus (IFOF) and the inferior longitudinalfasciculus (ILF) was significantly correlated with the cognitive scores in executivefunction and episodic memory in both the control and the mild WMLs group.Conclusion Together,1) our results firstly demonstrated that mild WMLs exhibitedabnormalities in both white matter structure and functional intrinsic brain activitymainly in frontal lobe. Considering intact gray matter structure, the structural changesof white matter resulting in disconnecting of brain areas might be one of the reasons ofcognitive decline, while frontal enhanced functional activity might be a compensationof cognitive impairment;2) combing multimodal neuroimaging techniques andneuropsychological tests is beneficial for better understanding early brain structuraland functional change of WMLs and their correlation with cognitive decline, whichproviding a very important theory and practical value in fundamental research aboutthe progression of WMLs and its related diseases. |
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