PDF(Pubmed)
Abstract：
BACKGROUND: The hemodynamics of prefrontal cortex (PFC) oxygenation are regulated by numerous processes operating over multiple temporal scales, producing complex patterns in its output fluctuations. Age may alter this multiscale regulation of PFC oxygenation, leading to diminished physiologic complexity of this important regulatory process. We aimed to characterize the effects of age on such complexity and its relationship to performance of an executive n-back task.
METHODS: Twenty-four younger (aged 28 ± 3 years) and 27 older (aged 78 ± 6 years) adults completed this study. Continuous oxygenation (HbO2) and deoxygenation (HHb) signals of PFC were recorded using functional near-infrared spectroscopy (fNIRS) while participants stood and watched a blank screen (blank), clicked a mouse when an X appeared (IdX), or when a letter was repeated from \"2-back\" in a sequence shown on a screen (2-back). We used multiscale entropy to quantify the HbO2 and HHb complexity of fNIRS signals.
RESULTS: Older adults exhibited lower HbO2 and HHb complexity compared to younger adults, regardless of task (p = .0005-.002). Both groups exhibited greater complexity during the IdX and 2-back than blank task (p = .02-.04). Across all participants, those with greater HbO2 and/or HHb complexity during the blank task exhibited faster IdX and 2-back reaction time (β = -0.56 to -0.6, p = .009-.02). Those demonstrating greater increase in HbO2 and/or HHb complexity from IdX to 2-back task had lower percent increase in reaction time from IdX to 2-back task (β = -0.41 to -0.37, p = .005-.01).
CONCLUSIONS: The complexity of fNIRS-measured PFC oxygenation fluctuations may capture the influence of aging on the regulation of prefrontal hemodynamics involved in executive-function-based task performance.
METHODS: Twenty-four younger (aged 28 ± 3 years) and 27 older (aged 78 ± 6 years) adults completed this study. Continuous oxygenation (HbO2) and deoxygenation (HHb) signals of PFC were recorded using functional near-infrared spectroscopy (fNIRS) while participants stood and watched a blank screen (blank), clicked a mouse when an X appeared (IdX), or when a letter was repeated from \"2-back\" in a sequence shown on a screen (2-back). We used multiscale entropy to quantify the HbO2 and HHb complexity of fNIRS signals.
RESULTS: Older adults exhibited lower HbO2 and HHb complexity compared to younger adults, regardless of task (p = .0005-.002). Both groups exhibited greater complexity during the IdX and 2-back than blank task (p = .02-.04). Across all participants, those with greater HbO2 and/or HHb complexity during the blank task exhibited faster IdX and 2-back reaction time (β = -0.56 to -0.6, p = .009-.02). Those demonstrating greater increase in HbO2 and/or HHb complexity from IdX to 2-back task had lower percent increase in reaction time from IdX to 2-back task (β = -0.41 to -0.37, p = .005-.01).
CONCLUSIONS: The complexity of fNIRS-measured PFC oxygenation fluctuations may capture the influence of aging on the regulation of prefrontal hemodynamics involved in executive-function-based task performance.
摘要：
背景：前额叶皮质（PFC）氧合的血流动力学受多个时间尺度上的许多过程的调节，在其产出波动中产生复杂的模式。年龄可能会改变PFC氧合的这种多尺度调节，导致这一重要调节过程的生理复杂性降低。我们旨在描述年龄对这种复杂性的影响及其与高管n-back任务绩效的关系。
方法：24名年龄较小（28±3岁）和27名年龄较大（78±6岁）的成年人完成了这项研究。使用功能近红外光谱（fNIRS）记录PFC的连续氧合（HbO2）和脱氧（HHb）信号，同时参与者站立并观看空白屏幕（空白），当出现X(IdX)或在屏幕(2-back)上显示的序列中从“2-back”重复字母时，单击鼠标。我们使用多尺度熵来量化fNIRS信号的HbO2和HHb复杂度。
结果：与年轻人相比，老年人表现出更低的HbO2和HHb复杂性，不管任务(p=0.0005~0.002)。两组在IdX和2-back期间的复杂性均高于空白任务（p=0.02〜0.04）。在所有参与者中，空白任务中HbO2和/或HHb复杂度较大的人表现出更快的IdX和2-back反应时间（β=-0.56〜-0.6，p=0.009〜0.02）。那些表现出从IdX到2-back任务的HbO2和/或HHb复杂性增加更大的人，从IdX到2-back任务的反应时间增加百分比较低（β=-0.41〜-0.37，p=0.005〜0.01）。
结论：fNIRS测量的PFC氧合波动的复杂性可能捕获了衰老对基于执行功能的任务表现所涉及的前额叶血流动力学调节的影响。
方法：24名年龄较小（28±3岁）和27名年龄较大（78±6岁）的成年人完成了这项研究。使用功能近红外光谱（fNIRS）记录PFC的连续氧合（HbO2）和脱氧（HHb）信号，同时参与者站立并观看空白屏幕（空白），当出现X(IdX)或在屏幕(2-back)上显示的序列中从“2-back”重复字母时，单击鼠标。我们使用多尺度熵来量化fNIRS信号的HbO2和HHb复杂度。
结果：与年轻人相比，老年人表现出更低的HbO2和HHb复杂性，不管任务(p=0.0005~0.002)。两组在IdX和2-back期间的复杂性均高于空白任务（p=0.02〜0.04）。在所有参与者中，空白任务中HbO2和/或HHb复杂度较大的人表现出更快的IdX和2-back反应时间（β=-0.56〜-0.6，p=0.009〜0.02）。那些表现出从IdX到2-back任务的HbO2和/或HHb复杂性增加更大的人，从IdX到2-back任务的反应时间增加百分比较低（β=-0.41〜-0.37，p=0.005〜0.01）。
结论：fNIRS测量的PFC氧合波动的复杂性可能捕获了衰老对基于执行功能的任务表现所涉及的前额叶血流动力学调节的影响。
