Age-Dependent Shifts in Diurnal Alternations of FPN Connectivity
Poster No:
881
Submission Type:
Abstract Submission
Authors:
Trong-Nguyen Nguyen1, Fan-Chi Hsiao2, Wen-Chi Chiu1, Hsin-Chien Lee1, Chien-Ming Yang3, Changwei Wu1
Institutions:
1Taipei Medical University, New Taipei, Taiwan, 2Ming Chuang University, Taoyuan, Taiwan, 3National Chengchi University, Taipei, Taiwan
First Author:
Co-Author(s):
Introduction:
Circadian rhythms (the periodic biological changes within 24 hours) have powerful and far-reaching impacts on human brain functions. However, the findings regarding time-of-day effect on large-scale brain network are inconsistent across multiple confounding factors (Park et al., 2012). Studies on healthy young adults have revealed rhythmic spontaneous functional connectivity in task-positive networks like the Frontal-Parietal Network (FPN), yet others have reported stability across different times of the day (Facer-Childs et al., 2019; Vaisvilaite et al., 2022). Emerging evidence suggests age-dependent circadian neuro-synchrony, as the neurocircadian endocrine system undergoes functional declines with age (Yamazaki et al., 2002). Hence, we aim to uncover the diurnal variations of the FPN network along the aging process and its associated psychological implications.
Methods:
33 younger adults (Mage = 23.3) and 30 older adults (Mage = 66) underwent two scanning sessions on a 3T Skyra MRI scanner, conducted in the morning (10 am) and afternoon (2 pm). Each session included a T1-weighted anatomical images and a resting-state fMRI, followed by a task session with Numerical Stroop task. Morning psychological assessments included Epworth Sleepiness Scale (ESS), Beck's Anxiety Inventory (BAI), and Beck's Depression Inventory (BDI).
All fMRI data were preprocessed using the default preprocessing pipeline in CONN (Nieto-Castanon, 2020). Resting-state functional connectivity within the FPN was quantified using voxel-wise seed-based correlation (SBC) analysis, with Fisher's Z transformation applied to measure spontaneous functional connectivity strength, seeded at the right Posterior Parietal Cortex (PPCr). Task-based connectivity was assessed using generalized psychophysiological interaction (gPPI) analysis, which evaluates task-dependent changes in connectivity.
In statistical analysis, a 2x2 mixed ANOVA (Age × Time of Day) with family-wise error (FWE) correction was conducted on fMRI indices. FPN-related regions, including the bilateral lateral prefrontal cortex (LPFC) and left PPC from the Harvard-Oxford atlas, was used to extract functional connectivity (FC) strengths. Pearson correlation analysis was subsequently used to evaluate the relationship between morning-to-afternoon changes in FC (∆FC) and psychological measures.
All fMRI data were preprocessed using the default preprocessing pipeline in CONN (Nieto-Castanon, 2020). Resting-state functional connectivity within the FPN was quantified using voxel-wise seed-based correlation (SBC) analysis, with Fisher's Z transformation applied to measure spontaneous functional connectivity strength, seeded at the right Posterior Parietal Cortex (PPCr). Task-based connectivity was assessed using generalized psychophysiological interaction (gPPI) analysis, which evaluates task-dependent changes in connectivity.
In statistical analysis, a 2x2 mixed ANOVA (Age × Time of Day) with family-wise error (FWE) correction was conducted on fMRI indices. FPN-related regions, including the bilateral lateral prefrontal cortex (LPFC) and left PPC from the Harvard-Oxford atlas, was used to extract functional connectivity (FC) strengths. Pearson correlation analysis was subsequently used to evaluate the relationship between morning-to-afternoon changes in FC (∆FC) and psychological measures.
Results:
The final sample size was 57 healthy individuals, including 28 older adults (Mage = 67±5) and 29 younger adults (Mage = 23±3). At rest, SBC analysis showed significant Age × Time interaction (FWE-corrected p < 0.05) at right anterior Middle Temporal Gyrus (aMTG). The PPCr exhibited the decreased connectivity to MTG for the Old group but increased that for the young group (F1,55 = 37.97, p < 0.001; post-hoc test: t28 = -5.63, p < 0.001; t29 = 2.96, p < 0.01). While performing task, gPPI analysis showed significance in right Frontal Pole (FPr). The connectivity of (PPCr-FPr) for the old group decreased in the afternoon but that for the young group increased (F1,55 = 27.87, p < 0.01; post-hoc test: t28 = -4.07, p < 0.001; t29 = 3.67, p < 0.01). Only young group decreased FPN within-network connectivity in the afternoon (F1,55 = 4.57, p < 0.05; post-hoc test: t28= 3.27, p = 0.003), and the time difference correlated with ESS (r = -0.43, p = 0.012), BAI (r = -0.48, p < 0.001) and BDI (r = -0.42, p = 0.014), only for the young group.
·Figure 1: Diurnal variations of FPN connectivity in both old and young groups.
·Figure 2: Association between the FPN connectivity changes and questionnaires in both age groups.
Conclusions:
We demonstrated that aging alters the diurnal variation of brain's functionality both at rest and during task. In both scenarios, the old group decreased within network functional connectivity in the afternoon, while the young group showed the opposite. Future investigation is needed to unveil the age-dependent functional dynamicity.
Lifespan Development:
Aging 1
Modeling and Analysis Methods:
Connectivity (eg. functional, effective, structural) 2
Perception, Attention and Motor Behavior:
Sleep and Wakefulness
Keywords:
Aging
FUNCTIONAL MRI
NORMAL HUMAN
Other - Circadian rhythm
1|2Indicates the priority used for review
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Were any human subjects research approved by the relevant Institutional Review Board or ethics panel? NOTE: Any human subjects studies without IRB approval will be automatically rejected.
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Provide references using APA citation style.
Nieto-Castanon, A. (2020). Handbook of functional connectivity magnetic resonance imaging methods in CONN. Hilbert Press.
Park, B., Kim, J. I., Lee, D., Jeong, S.-O., Lee, J. D., & Park, H.-J. J. N. (2012). Are brain networks stable during a 24-hour period? , 59(1), 456-466
Vaisvilaite, L., Hushagen, V., Grønli, J., & Specht, K. (2022). Time-of-day effects in resting-state functional magnetic resonance imaging: Changes in effective connectivity and blood oxygenation level dependent signal. Brain Connectivity, 12(6), 515-523.
Yamazaki S et al. (2002) Effects of aging on central and peripheral mammalian clocks. Proc Natl Acad Sci USA 99:10801 10806.