A Longitudinal Functional Magnetic Resonance Imaging Study of Working Memory in Patients Following a Transient Ischemic Attack: A Preliminary Study
Wei Su1,2• Jian Guo1• Yun Zhang3• Jie Zhou1• Ning Chen1• Muke Zhou1• Rong Li4• Huafu Chen4• Li He1,*
1Department of Neurology, West China Hospital of Sichuan University, Chengdu 610041, China
2Department of Science and Technology, West China Hospital of Sichuan University, Chengdu 610041, China
3Department of Neurology, Mianyang Central Hospital, Mianyang 621000, China
4Key Laboratory for Neuroinformation of The Ministry of Education, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 610041, China
In this study, we used functional magnetic resonance imaging (fMRI) to investigate longitudinal changes in brain activation during a verbal working memory (VWM) task performed by patients who had experienced a transient ischemic attack (TIA). Twenty-five first-ever TIA patients without visible lesions in conventional MRI and 25 healthy volunteers were enrolled. VWM task-related fMRI was conducted 1 week and 3 months post-TIA. The brain activity evoked by the task and changes over time were assessed. We found that, compared with controls, patients exhibited an increased activation in the bilateral inferior frontal gyrus (IFG), right dorsolateral prefrontal cortex (DLPFC), insula, inferior parietal lobe (IPL), and cerebellum during the task performed 1 week post-TIA. But only the right IFG still exhibited an increased activation at 3 months post-TIA. A direct comparison of fMRI data between 1 week and 3 months post-TIA showed greater activation in the bilateral middle temporal gyrus, right DLPFC, IPL, cerebellum, and left IFG in patients at 1 week post-TIA. We conclude that brain activity patterns induced by a VWM task remain dynamic for a period of time after a TIA, despite the cessation of clinical symptoms. Normalization of the VWM activation pattern may be progressively achieved after transient episodes of ischemia in TIA patients.