Gut microbiota interacts with intrinsic brain activity of patients with amnestic mild cognitive impairment

Aims To explore the potential relationships among gut microbiota (GM), local brain spontaneous activity, and neuropsychological characteristics in amnestic mild cognitive impairment (aMCI) patients. Methods Twenty aMCI and 22 healthy control (HC) subjects were recruited. The GM composition was determined by 16S ribosomal RNA gene sequencing. Resting-state functional magnetic resonance imaging scans were performed, and fractional amplitude of low-frequency fluctuations (fALFF) was calculated across different frequencies. The Spearman or Pearson correlation analysis was used to analyze the relationship between spontaneous brain activity and cognitive function, and GM composition. Results aMCI patients had altered GM state and local spontaneous brain activity as compared with HC subjects. Correlation analysis showed that aMCI and HC groups had different "GM-intrinsic brain activity interaction" patterns. In aMCI group, at the typical band (0.01-0.08 Hz), the relative abundance (RA) of Bacteroides from phylum to genus level was negatively correlated with fALFF value of cerebellar vermis IV-V, and theRuminococcaceaeRA was negatively correlated with fALFF values of left lenticular nucleus and pallidum. TheClostridiaceaeRA andBlautiaRA were positively correlated with the left cerebellum lobules IV-V at the slow-4 band (0.027-0.073 Hz). TheVeillonellaceaeRA was positively correlated with fALFF values of left precentral gyrus at the slow-5 band (0.073-0.08 Hz). Correlation analysis showed that Clostridium members (LachnospiraceaeandBlautia) were positively, whileVeillonellaceaewas negatively, correlated with cognition test. Bacteroides was positively correlated with attention and computation, and negatively correlated with the three-stage command score. Conclusions aMCI patients have a specific GM-intrinsic brain activity-cognitive function interaction pattern.