The Resting-state FMRI Study Of Transient Ischemic Attacks

Transient Ischemic Attacks (TIA) is a usual cerebrovascular disease (CVD), andmore and more people has paid attention to it. There are also many methods which wereused in the studies of this disease. In recent years, the resting-state fMRI has became anew brain function imaging technique, but it has been rarely used for TIA. The purposeof this study is to detect brain dysfunction of TIA patients from two directions of bothlocal regions and the whole brain using resting-state fMRI. In the study, we usedregional homogeneity approach to assess local synchronization of spontaneous bloodoxygen level-dependent (BOLD) activity during resting state, and found that TIApatients revealed significantly reduced ReHo. The reduction of ReHo was not limited toa special brain region, but widely distributed on left precentral gyrus, left postcentralgyrus, left parietal lobe, right inferior frontal orbital cortex and pars triangular, rightposterior inferior frontal gyrus, right middle frontal gyrus, right insula and right middlecingulate gyrus of the limbic lobe. Among them, the precentral gyrus and postcentralgyrus may be involved in the somatosensory and motor injure in TIA patients; thedamage of cingulate gyrus could lead to memory impairment and depression after theillness of TIA patients; the impairment of insula should be responsible for dysfunctionof somatic sensation and higher cognition; the damage of the middle frontal gyrus andinferior frontal gyrus may be related with dysmnesia and aphasia. Our findings suggestthat the functional damage of TIA patients is closely related with local synchronizationof spontaneous BOLD activity in resting state, which will provide evidences for furtherstudy of TIA.In the research, in order to detect functional connectivity within resting statenetworks in TIA patients, we investigated differences in RSNs on TIA patients andhealthy controls using independent component analysis. A diffuse impact on widelydistributed RSNs and selective changes of RSN intrinsic functional connectivity wereobserved in TIA patients. Functional connectivity was increased or decreased in thedefault mode network which may be suggested to be involved in the function of motion,language and memory, and the self referential processes which were thought to be involved in the regulation of somatic sensation and the recovery process, and decreasedin all other networks in TIA patients. Among the decreased networks, the changes ofdorsal attention network may affect the function of cognitive control and maintain; theabnormalities of central-executive network could lead to the impairment of cognitiveregulation and processing; the changes of core network which is a task-related networkaffect the function of attention and execution; the somato-motor, visual and auditorynetwork are the perceptual systems, their abnormalities should be related with theimpairment of the lower-order of the cognitive processing. Our findings are in line withprevious studies which researched TIA or ischemic stroke. Overall, our studies showthat TIA results in aberrant functional connectivity of resting state networks and affectsthe primary perception and advanced cognition.