Altered dynamic regional homogeneity and neurovascular coupling in multi-frequency bands in patients with cerebral...

Cerebral small vessel disease (CSVD) can lead to neurologic deficits and cerebral perfusion injuries. However, the dynamic characteristics of neural function homogeneity and their coupling with cerebral perfusion are rarely elucidated in the sub-frequency bands. The purpose of this study is to explore these features for further understanding of the neural mechanisms of CSVD.

In this cross-sectional study, we obtained magnetic resonance imaging (MRI) data and a series of cognitive scores from 27 CSVD patients with mild cognitive impairment (CSVD-MCI), 32 CSVD patients with cognitive unimpaired (CSVD-CU) and 30 normal controls (NC). The dynamic regional homogeneity (dReHo) and cerebral blood flow (CBF) analyses were utilized to explore the dynamic neural function homogeneity and neurovascular coupling (dReHo-CBF correlation coefficient and CBF/dReHo ratio) in conventional frequency band (0.01-0.08 Hz) and two sub-frequency bands (slow-4: 0.027-0.073 Hz and slow-5: 0.01-0.027 Hz). The partial correlation analysis was used to investigate the relationships between the above MRI indicators and the cognitive scores in the patient group.

CSVD-MCI group showed significantly abnormal dReHo values and CBF/dReHo ratios in multiple brain regions in conventional frequency band, including the left middle occipital gyrus, right inferior temporal gyrus, left anterior cingulate gyrus, and right thalamus (P<0.05). The brain regions with significantly abnormal dReHo and CBF/dReHo ratios in the sub-frequency bands were similar to those in the conventional frequency band. These abnormal values of the right inferior occipital gyrus, right inferior temporal gyrus, and left anterior cingulate gyrus in sub-frequency bands were significantly related to cognitive scores (P<0.05). Moreover, CSVD-CU group only showed a significant decrease in the CBF/dReHo ratio of the left occipital gyrus in the conventional frequency band (P<0.05).

Our findings showed that CSVD patients exhibited impaired dynamic patterns of neuronal synchronization and disrupted neurovascular coupling prior to the onset of dementia, which were associated with cognitive impairment in sub-frequency bands.