Variations in the frequency and amplitude of resting-state EEG and fMRI signals in normal adults: The effects of age and sex

Abstract

Frequency and amplitude features of both resting-state electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) are crucial metrics that reveal patterns of brain health in aging. However, the association between these two modalities is still unclear. In this study, we examined the peak frequency and standard deviation of both modalities in a dataset comprising healthy young (35.5±3.4 years, N=134) and healthy old (66.9±4.8 years, N=51) adults. Both age and sex effects were examined using non-parametric analyses of variance (ANOVA) and Tukey’s Honest Significant Difference (HSD) post-hoc comparisons in the cortical and subcortical regions. We found that, with age, EEG power decreases in the low frequency band (1-12 Hz) but increases in the high frequency band (12-30 Hz). Moreover, EEG frequency generally shifts up with aging. For fMRI, fluctuation amplitude is lower but fluctuation frequency is higher in older adults, but in a manner that depends on the fMRI frequency range. Furthermore, there are significant sex effects in EEG power (female > male), but the sex effect is negligible for EEG frequency as well as fMRI power and frequency. We also found that the fMRI-EEG power ratio is higher in young adults than old adults. However, the mediation analysis shows the association between EEG and fMRI parameters in aging is negligible. This is the first study that examines both power and frequency of both resting EEG and fMRI signals in the same cohort. In conclusion, both fMRI and EEG signals reflect age-related and sex-related brain differences, but they likely associate with different origins.

Maternal psychological distress associates with alterations in resting‐state low‐frequency fluctuations and distal functional connectivity of the neonate medial prefrontal cortex

“…These brain changes were further hypothesized to be related with disrupted network-level flexibility, for example, the inability to coherently decrease and increase brain region activity when engaging in mathematical tasks (Jolles et al, 2016). Prior multimodal studies performed on adults have shown that fMRI and EEG signal amplitudes are modulated by effects of aging and sex (Zhong & Chen, 2020), with the hypothesis that as vasculature reactivity declines with age, so does BOLD-signal amplitude (Zhong & Chen, 2020). Contrarily, frequency bands of MEG-fMRI measurements follow similar power-law distributions with electrophysiological signals, suggesting that intensity of low-frequency modulations stem from neural activity rather than neurovascular coupling effects (Zhang et al, 2022).…”

Normative brain mapping using scalp EEG and potential clinical application

“…This limitation may have directly influenced the iEEG results. Furthermore, previous work suggests a potential age effect on band power profiles in children 59 , 60 and in elderly 61 , 62 , which was not investigated in our study of adult participants. We also used a single template MRI (ICMB152) to build realistic head models that limits the anatomical precision of source localisation.…”

The modulatory effect of adaptive task-switching training on resting-state neural network dynamics in younger and older adults

“…Corresponding to the age-related differences in temporal neural dynamics, resting-state spectral power also shows significant differences in frequency band power between younger and older individuals 97 . Even though there are inconsistencies in the current literature, in general, low frequencies (delta, theta, alpha bands) show decreased power 91,[98][99][100] , while higher frequencies (beta) show increased power 92,101 with healthy aging (i.e., and age-related shift in spectral power density; [102][103][104][105][106][107] ). These results are in line with the age-related brain signal complexity changes, namely the decreased power in lower frequency bands with healthy aging can be linked to decreased coarse time scale entropy while the increased power in higher frequency bands can be linked to increased fine time scale entropy 88 .…”