AUTHOR=Zhang Miao , Sun Wanqing , Guan Ziyun , Hu Jialin , Li Binyin , Ye Guanyu , Meng Hongping , Huang Xinyun , Lin Xiaozhu , Wang Jin , Liu Jun , Li Biao , Zhang Yaoyu , Li Yao 

TITLE=Simultaneous PET/fMRI Detects Distinctive Alterations in Functional Connectivity and Glucose Metabolism of Precuneus Subregions in Alzheimer’s Disease

JOURNAL=Frontiers in Aging Neuroscience

VOLUME=13

YEAR=2021

URL=https://www.frontiersin.org/journals/aging-neuroscience/articles/10.3389/fnagi.2021.737002

DOI=10.3389/fnagi.2021.737002

ISSN=1663-4365

ABSTRACT=<p>As a central hub in the interconnected brain network, the precuneus has been reported showing disrupted functional connectivity and hypometabolism in Alzheimer’s disease (AD). However, as a highly heterogeneous cortical structure, little is known whether individual subregion of the precuneus is uniformly or differentially involved in the progression of AD. To this end, using a hybrid PET/fMRI technique, we compared resting-state functional connectivity strength (FCS) and glucose metabolism in dorsal anterior (DA_pcu), dorsal posterior (DP_pcu) and ventral (V_pcu) subregions of the precuneus among 20 AD patients, 23 mild cognitive impairment (MCI) patients, and 27 matched cognitively normal (CN) subjects. The sub-parcellation of precuneus was performed using a K-means clustering algorithm based on its intra-regional functional connectivity. For the whole precuneus, decreased FCS (<italic>p</italic> = 0.047) and glucose hypometabolism (<italic>p</italic> = 0.006) were observed in AD patients compared to CN subjects. For the subregions of the precuneus, decreased FCS was found in DP_pcu of AD patients compared to MCI patients (<italic>p</italic> = 0.011) and in V_pcu for both MCI (<italic>p</italic> = 0.006) and AD (<italic>p</italic> = 0.008) patients compared to CN subjects. Reduced glucose metabolism was found in DP_pcu of AD patients compared to CN subjects (<italic>p</italic> = 0.038) and in V_pcu of AD patients compared to both MCI patients (<italic>p</italic> = 0.045) and CN subjects (<italic>p</italic> &lt; 0.001). For both FCS and glucose metabolism, DA_pcu remained relatively unaffected by AD. Moreover, only in V_pcu, disruptions in FCS (<italic>r</italic> = 0.498, <italic>p</italic> = 0.042) and hypometabolism (<italic>r</italic> = 0.566, <italic>p</italic> = 0.018) were significantly correlated with the cognitive decline of AD patients. Our results demonstrated a distinctively disrupted functional and metabolic pattern from ventral to dorsal precuneus affected by AD, with V_pcu and DA_pcu being the most vulnerable and conservative subregion, respectively. Findings of this study extend our knowledge on the differential roles of precuneus subregions in AD.</p>