title: Age-related alterations in phase synchronization of oxyhemoglobin concentration changes in prefrontal tissues as measured by near-infrared spectroscopy signals.
abstract: The prefrontal cortex plays an important role in planning complex cognitive behavior, personality expression, and decision making. This study aims to assess the phase synchronization of signals of the oxyhemoglobin concentration changes (Δ[HbO2]) in the left and right prefrontal tissues through near-infrared spectroscopy (NIRS) with wavelet phase coherence (WPCO) method. The NIRS signals were continuously recorded from the left and right prefrontal lobes in 43 healthy elderly subjects (age: 69.6 ± 8.4 years) and 40 young healthy subjects (age: 24.5 ± 1.7 years) during the resting state. Phase synchronization between the left and right prefrontal oscillations in six frequency intervals (I, 0.6-2 Hz; II, 0.145-0.6 Hz; III, 0.052-0.145 Hz; IV, 0.021-0.052 Hz; V, 0.0095-0.021 Hz; and VI, 0.005-0.0095 Hz) was analyzed using the WPCO method. The WPCO values of elderly subjects were significantly lower in frequency intervals I (F=7.376, p=0.010) and III (F=6.418, p=0.016) than those of the young subjects. Low phase coherence in intervals I and III indicates reduced synchronization of cardiac activity in the prefrontal area and weakened prefrontal functional connectivity, respectively.
authors.affiliation: Key Laboratory of High Efficiency and Clean Mechanical Manufacture, School of Mechanical Engineering, Shandong University, Jinan 250061, PR China.
authors.forename: Qitao
authors.initials: Q
authors.lastname: Tan
authors.affiliation: Interdisciplinary Division of Biomedical Engineering, Faculty of Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong, SAR, PR China.
authors.forename: Ming
authors.initials: M
authors.lastname: Zhang
authors.affiliation: Department of Dermatology, Ji'nan Central Hospital, 250013, PR China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Key Laboratory of High Efficiency and Clean Mechanical Manufacture, School of Mechanical Engineering, Shandong University, Jinan 250061, PR China.
authors.forename: Manyu
authors.initials: M
authors.lastname: Zhang
authors.affiliation: Key Laboratory of High Efficiency and Clean Mechanical Manufacture, School of Mechanical Engineering, Shandong University, Jinan 250061, PR China.
authors.forename: Bitan
authors.initials: B
authors.lastname: Wang
authors.affiliation: Hospital of Shandong University, Jinan 250061, PR China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Xin
authors.affiliation: Key Laboratory of High Efficiency and Clean Mechanical Manufacture, School of Mechanical Engineering, Shandong University, Jinan 250061, PR China. Electronic address: zyongli@sdu.edu.cn.
authors.forename: Zengyong
authors.initials: Z
authors.lastname: Li
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000375:Aging / Q000097:blood* / Q000523:psychology; D015415:Biomarkers / Q000097:blood; D001794:Blood Pressure; D002560:Cerebrovascular Circulation; D003071:Cognition; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D009991:Oscillometry; D010092:Oximetry / Q000379:methods*; D010108:Oxyhemoglobins / Q000378:metabolism*; D011237:Predictive Value of Tests; D017397:Prefrontal Cortex / Q000098:blood supply* / Q000378:metabolism*; D019265:Spectroscopy, Near-Infrared; D013997:Time Factors; D058067:Wavelet Analysis; D055815:Young Adult
chemical_list: D015415:Biomarkers; D010108:Oxyhemoglobins
keywords: Cerebral oxygenation; Functional connectivity; Near-infrared spectroscopy; Spontaneous oscillations; Wavelet coherence; Wavelet phase coherence