Alteration in Brain Functional and Effective Connectivity in Subjects With Hypertension

• Published in: Frontiers in physiology Vol. 9; p. 669
• Main Authors: Bu, Lingguo, Huo, Congcong, Xu, Gongcheng, Liu, Ying, Li, Zengyong, Fan, Yubo, Li, Jianfeng
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Media S.A 31.05.2018
• Subjects: effective connectivity; functional connectivity; hypertension; near-infrared spectroscopy; Physiology; posture change; wavelet phase coherence; near-infrared spectroscopy; coupling strength; functional connectivity; effective connectivity; wavelet phase coherence; hypertension; posture change
• DOI: 10.3389/fphys.2018.00669
• ISSN: 1664-042X

To reveal the physiological mechanism of the cognitive decline in subjects with hypertension, the functional connectivity (FC) was assessed by using the wavelet phase coherence (WPCO), and effective connectivity (EC) was assessed by using the coupling strength (CS) of near-infrared spectroscopy (NIRS) signals. NIRS signals were continuously recorded from the prefrontal cortex, sensorimotor cortex, and occipital lobes of 13 hypertensive patients (hypertension group, 70 ± 6.5 years old) and 16 elderly healthy subjects (control group, 71 ± 5.5 years old) in resting and standing periods. WPCO and CS were calculated in four frequency intervals: I, 0.6-2; II, 0.145-0.6; III, 0.052-0.145; and IV, 0.021-0.052 Hz. CS quantifies coupling amplitude. In comparison with the control group, the hypertension group showed significantly decreased ( < 0.05) WPCO and CS in intervals III and IV and in the resting and standing states. WPCO and CS were significantly decreased in the resting state compared with those in the standing state in the hypertension group ( < 0.05). Decreased WPCO and CS indicated a reduced network interaction, suggesting disturbed neurovascular coupling in subjects with hypertension. Compared with the control group, the hypertension group showed significantly lower Mini-Mental State Examination (MMSE) ( = 0.028) and Montreal Cognitive Assessment (MoCA) scores ( = 0.011). In the hypertension group, correlation analysis showed that WPCO and CS were significantly positively correlated with MMSE and MoCA scores, respectively. These findings may provide evidence of impaired cognitive function in hypertension and can enhance the understanding on neurovascular coupling.