The Study Of Functional Connectivity And Effective Connectivity In Executive Function In Patients With Post-stroke Cognitive Impairment

Executive function is an essential part of higher brain functions and plays an important role in attentional control,inhibitory control,working memory,and cognitive flexibility.Executive impairment can lead to functional impairment in multiple domains,including cognition,motor,and emotion.The most significant early abnormality of cognitive domains in patients with post-stroke cognitive impairment is executive impairment,which can lead to reduced quality of life,independent functioning,and work capacity in the chronic phase of stroke.Previous functional magnetic resonance studies have shown that abnormal executive function in patients with post-stroke cognitive impairment were associated with disrupted functional connectivity in the frontoparietal network.Considering that functional connectivity only reflects the correlation and synchronization of neural activity between brain regions,a combination of effective connectivity would allow a more comprehensive and in-depth investigation of the neural basis of abnormal executive function in patients with post-stroke cognitive impairment from the perspective of time-series correlation and directional interactions between brain regions.In addition,depression is another post-stoke impairment that is strongly associated with post-stroke cognitive impairment in terms of prevalence,pathological mechanism,and treatment.Executive impairment is also frequently demonstrated in post-stroke depression and is associated with stroke recurrence and death.Therefore,further investigate the effect of depression on executive function in patients with post-stroke cognitive impairment would help to better elucidate the neural basis of executive function related to post-stroke cognitive impairment.The current study consists of two sub-studies.The first sub-study extracted the frontoparietal network using independent component analysis and used the three most significant brain regions in the frontoparietal network(right middle temporal gyrus,right middle frontal gyrus and right angular gyrus)as regions of interest to examine the executive function network and effective connectivity network in patients with post-stroke cognitive impairment using seed-based resting state functional connectivity and coefficient-based Granger causality analysis,respectively.The results showed that patients with post-stroke cognitive impairment had impaired functional connectivity between brain regions involved in executive function,language,and overall cognitive function.And abnormal effective connectivity was found between widely distributed brain areas involved in processing such as working memory and executive control,cognitive processing,self-processing and auditory in post-stroke cognitive impairment.On the basis of first sub-study,we further examined the effects of depression on executive function networks and effective connectivity networks in patients with post-stroke cognitive impairment at second sub-study.It was found that depression affected the neural basis of executive function in patients with post-stroke cognitive impairment,as evidenced by changes in the direction of information transfer between certain brain regions.In summary,we found that abnormal executive function in post-stroke cognitive impairment is associated with abnormal functional connectivity or effective connectivity between brain regions involved in multiple functions throughout the brain,and that depression indeed affect the neural basis of executive function in patients with post-stroke cognitive impairment.The current study was able to improve the understanding of the neural basis of executive function in patients with post-stroke cognitive impairment and considered the effects of depression on executive function in patients with post-stroke cognitive impairment,which could provide a new perspective for future early clinical screening and treatment of patients with post-stroke cognitive impairment.