Age-related changes in aperiodic electrophysiological activity, typically interpreted as neural, can be significantly explained by cardiac activity rather than solely cortical sources.
Cross-Sectional (n=1,282)
Age-related changes in aperiodic electrophysiological activity often attributed to neural sources are significantly confounded by cardiac activity, highlighting the need for better artifact separation.
Abstract The power of electrophysiologically measured cortical activity decays with an approximately 1/fX function. The slope of this decay (i.e. the spectral exponent, X) is modulated by various factors such as age, cognitive states or psychiatric/neurological disorders. Interestingly, a mostly parallel line of research has also uncovered similar effects for the spectral slope in the electrocardiogram (ECG). This raises the question whether these bodywide changes in spectral slopes are (in-)dependent. Focusing on well-established age-related changes in spectral slopes we analyzed a total of 1282 recordings of magnetoencephalography (MEG) resting state measurements with concurrent ECG in an age-diverse sample (18-88 years). Using a diverse array of analytical approaches, we demonstrate that the aperiodic signal recorded via surface electrodes/sensors originates from multiple physiological sources. Furthermore, our results suggest that common “artifact” rejection approaches (i.e. ICA) may not be sufficient to separate cardiac from neural activity. In particular, significant parts of age-related changes in aperiodic activity normally interpreted to be of neural origin can be explained by cardiac activity. Moreover, our results suggest that changes (flattening/steepening) of the spectral slope with age are dependent on the recording site and investigated frequency range. Our results highlight the complexity of aperiodic activity while raising concerns when interpreting aperiodic activity as “cortical“ without considering physiological influences.
Schmidt et al. (Mon,) reported a cross-sectional. Age was evaluated on Origin of age-related changes in aperiodic activity. Age-related changes in aperiodic electrophysiological activity, typically interpreted as neural, can be significantly explained by cardiac activity rather than solely cortical sources.