Abstract
To explore the alterations in the functional connectivity (FC) of subregions of nucleus accumbens (NAc) in Alzheimer's disease (AD) and explore their association with clinical cognitive scores. 45 AD patients (57–89 years old) and 41 age - and sex-matched healthy controls (HC) were recruited in this study. Four subregions of the NAc were used as regions of interest for whole-brain FC analysis. A series of comprehensive neuropsychological tests was conducted for all of the subjects. And correlation analyses were conducted to explore the relationships between the changed FC of brain regions with significant differences and the clinical scores. Compared with the HCs, decreased FC was observed between NAc subregions and regions of the orbitofrontal cortex (OFC), precuneus (PCUN), insula(INS), cerebellum 8 and putamen in AD patients (Gaussian random field (GRF) corrected, voxel-level P < 0.001, cluster-level P < 0.05). Furthermore, the FC between the left core and the left PCUN was correlated with the score of the Clock-Drawing Test (r = 0.319, P = 0.039), and the FC between the right core and the left insula was correlated with the score of HAMA scale in AD patients (r=-0.310, P = 0.046). The FC between the left PCUN and the left NAc subregions were both associated with the episodic memory function in AD patients (r = 0.441, P = 0.003; r = 0.330, P = 0.033). The changes in the FC of the four subregions of NAc might affect patients' self-awareness, decision execution, as well as social emotion, providing fresh propositions into the neural mechanisms of the reward circuit in AD patients.