Characterizing the middle-age neurophysiology using EEG/MEG

Abstract

Middle adulthood - the period of life between 40 and 60 years of age - is accompanied by important physical and emotional changes, as well as cognitive and neuronal ones. Nevertheless, middle age is often overlooked in neuroscience under the assumption that this is a time of relative stability, although cognitive decline, as well as changes in brain structure and function are well-established by the age of 60. Here we characterized the middle-aged brain in the context of healthy younger and older adults by assessing resting-state electrophysiological and neuromagnetic activity in two different samples (N = 179, 631). Alpha and beta oscillations - two key ageing signatures - were analyzed in terms of spectral power and burst events. While posterior alpha power and burst rate features changed linearly with age, similarly to behavioral measures, sensorimotor beta power and burst rate properties varied non-linearly, with inflection points during middle age. The findings suggest that ageing is characterized by distinct spatial and temporal brain dynamics, some critically arising in middle age.

Lifespan Oscillatory Dynamics in Lexical Production: A Population-based MEG Resting-State Analysis

“…Importantly, our study reaffirms that midlife is a turning point for spontaneous network oscillatory dynamics underlying language performance, consistent with previous MEG 62,63 , time-averaged fMRI 12 , and diffusion-weighted imaging (DWI) 19,64 . This further underscores the importance of studying the middle-aged brain from a multimodal perspective 65,66 as this period of life could be "prognostic of future cognitive outcomes" 67 .…”

“…Given the nonlinear age trajectory reported in MEG studies 62 , we generated two piecewise polynomials that we included as separate variables in our models. The quadratic term used to generate the polynomials was centered at 55 years old based on converging evidence in different imaging modalities 19,66,67,113 and matched to the original scale of the age variable.…”