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 the Ruminococcaceae RA was negatively correlated with fALFF values of left lenticular nucleus and pallidum. The Clostridiaceae RA and Blautia RA were positively correlated with the left cerebellum lobules IV‐V at the slow‐4 band (0.027‐0.073 Hz). The Veillonellaceae RA 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 (Lachnospiraceae and Blautia) were positively, while Veillonellaceae was 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.
Objective: This study aimed to determine the effects of high-frequency repetitive transcranial magnetic stimulation (rTMS) on cerebral hemodynamics in patients with disorders of consciousness (DOC). Methods: In this sham-controlled study, 20-Hz and sham rTMS were applied over the left primary motor cortex (M1) of 5 patients in a vegetative state (VS) and 5 patients in a minimally conscious state (MCS). The clinical behavior and cerebral blood flow (CBF) velocity in the bilateral middle cerebral artery (MCA) of the patients were evaluated before and after rTMS. Results: Compared with the VS group, the MCS group exhibited significant increases in peak systolic velocity (PSV; p = 0.024) and mean flow velocity (MFV) of the left MCA that were temporally related to the rTMS (p = 0.042). There were no significant effects on CBF velocity in the sham-stimulation group or the right MCA. Conclusions: High-frequency rTMS exerts different effects on CBF depending on the level of consciousness in patients with DOC such that it increased PSV and MFV in patients in a MCS. These effects may be related to the varying degrees of disrupted neurovascular coupling and the autonomic control of the cerebral hemodynamics in patients in a VS or MCS.
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