title: Changes of functional connectivity in the left frontoparietal network following aphasic stroke.
abstract: Language is an essential higher cognitive function supported by large-scale brain networks. In this study, we investigated functional connectivity changes in the left frontoparietal network (LFPN), a language-cognition related brain network in aphasic patients. We enrolled 13 aphasic patients who had undergone a stroke in the left hemisphere and age-, gender-, educational level-matched controls and analyzed the data by integrating independent component analysis (ICA) with a network connectivity analysis method. Resting state functional magnetic resonance imaging (fMRI) and clinical evaluation of language function were assessed at two stages: 1 and 2 months after stroke onset. We found reduced functional connectivity between the LFPN and the right middle frontal cortex, medial frontal cortex, and right inferior frontal cortex in aphasic patients as compared to controls. Correlation analysis showed that stronger functional connectivity between the LFPN and the right middle frontal cortex and medial frontal cortex coincided with more preserved language comprehension ability after stroke. Network connectivity analysis showed reduced LFPN connectivity as indicated by the mean network connectivity index of key regions in the LFPN of aphasic patients. The decreased LFPN connectivity in stroke patients was significantly associated with the impairment of language function in their comprehension ability. We also found significant association between recovery of comprehension ability and the mean changes in intrinsic LFPN connectivity. Our findings suggest that brain lesions may influence language comprehension by altering functional connectivity between regions and that the patterns of abnormal functional connectivity may contribute to the recovery of language deficits.
authors.affiliation: Department of Neurology, Dongzhimen Hospital, Beijing University of Chinese Medicine Beijing, China ; Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School Boston, MA, USA.
authors.forename: Dan
authors.initials: D
authors.lastname: Zhu
authors.affiliation: Department of Neurology, Dongzhimen Hospital, Beijing University of Chinese Medicine Beijing, China.
authors.forename: Jingling
authors.initials: J
authors.lastname: Chang
authors.affiliation: Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School Boston, MA, USA.
authors.forename: Sonya
authors.initials: S
authors.lastname: Freeman
authors.affiliation: Department of Radiology, Dongzhimen Hospital, Beijing University of Chinese Medicine Beijing, China.
authors.forename: Zhongjian
authors.initials: Z
authors.lastname: Tan
authors.affiliation: Department of Neurology, Dongzhimen Hospital, Beijing University of Chinese Medicine Beijing, China.
authors.forename: Juan
authors.initials: J
authors.lastname: Xiao
authors.affiliation: Department of Neurology, Dongzhimen Hospital, Beijing University of Chinese Medicine Beijing, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Gao
authors.affiliation: Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School Boston, MA, USA.
authors.forename: Jian
authors.initials: J
authors.lastname: Kong
keywords: aphasia; functional connectivity; independent component analysis; network connectivity analysis; the left frontoparietal network