TY - JOUR
T1 - Frequency and amplitude modulation of resting-state fMRI signals and their functional relevance in normal aging
AU - Yang, Albert C.
AU - Tsai, Shih Jen
AU - Lin, Ching Po
AU - Peng, Chung Kang
AU - Huang, Norden E.
N1 - Publisher Copyright:
© 2018 Elsevier Inc.
PY - 2018/10
Y1 - 2018/10
N2 - The intrinsic composition and functional relevance of resting-state blood oxygen level–dependent signals are fundamental in research using functional magnetic resonance imaging (fMRI). Using the Hilbert–Huang Transform to estimate high-resolution time-frequency spectra, we investigated the instantaneous frequency and amplitude modulation of resting-state fMRI signals, as well as their functional relevance in a large normal-aging cohort (n = 420, age = 21–89 years). We evaluated the cognitive function of each participant and recorded respiratory signals during fMRI scans. The results showed that the Hilbert–Huang Transform effectively categorized resting-state fMRI power spectra into high (0.087–0.2 Hz), low (0.045–0.087 Hz), and very-low (≤0.045 Hz) frequency bands. The high-frequency power was associated with respiratory activity, and the low-frequency power was associated with cognitive function. Furthermore, within the cognition-related low-frequency band (0.045–0.087 Hz), we discovered that aging was associated with the increased frequency modulation and reduced amplitude modulation of the resting-state fMRI signal. These aging-related changes in frequency and amplitude modulation of resting-state fMRI signals were unaccounted for by the loss of gray matter volume and were consistently identified in the default mode and salience network. These findings indicate that resting-state fMRI signal modulations are dynamic during the normal aging process. In summary, our results refined the functionally related blood oxygen level–dependent frequency band in a considerably narrow band at a low-frequency range (0.045–0.087 Hz) and challenged the current method of resting-fMRI preprocessing by using low-frequency filters with a relatively wide range below 0.1 Hz.
AB - The intrinsic composition and functional relevance of resting-state blood oxygen level–dependent signals are fundamental in research using functional magnetic resonance imaging (fMRI). Using the Hilbert–Huang Transform to estimate high-resolution time-frequency spectra, we investigated the instantaneous frequency and amplitude modulation of resting-state fMRI signals, as well as their functional relevance in a large normal-aging cohort (n = 420, age = 21–89 years). We evaluated the cognitive function of each participant and recorded respiratory signals during fMRI scans. The results showed that the Hilbert–Huang Transform effectively categorized resting-state fMRI power spectra into high (0.087–0.2 Hz), low (0.045–0.087 Hz), and very-low (≤0.045 Hz) frequency bands. The high-frequency power was associated with respiratory activity, and the low-frequency power was associated with cognitive function. Furthermore, within the cognition-related low-frequency band (0.045–0.087 Hz), we discovered that aging was associated with the increased frequency modulation and reduced amplitude modulation of the resting-state fMRI signal. These aging-related changes in frequency and amplitude modulation of resting-state fMRI signals were unaccounted for by the loss of gray matter volume and were consistently identified in the default mode and salience network. These findings indicate that resting-state fMRI signal modulations are dynamic during the normal aging process. In summary, our results refined the functionally related blood oxygen level–dependent frequency band in a considerably narrow band at a low-frequency range (0.045–0.087 Hz) and challenged the current method of resting-fMRI preprocessing by using low-frequency filters with a relatively wide range below 0.1 Hz.
KW - Aging
KW - Blood oxygen level–dependent signal
KW - Frequency and amplitude
KW - Functional magnetic resonance imaging
KW - Hilbert–Huang transform
UR - http://www.scopus.com/inward/record.url?scp=85049313348&partnerID=8YFLogxK
U2 - 10.1016/j.neurobiolaging.2018.06.007
DO - 10.1016/j.neurobiolaging.2018.06.007
M3 - 期刊論文
C2 - 30007165
AN - SCOPUS:85049313348
SN - 0197-4580
VL - 70
SP - 59
EP - 69
JO - Neurobiology of Aging
JF - Neurobiology of Aging
ER -