Decreased/increased beta/alpha functional connectivity in pathological and healthy aging. A dual pattern of brain dynamics revealed by magnetoencephalography

Abstract Background Alzheimer’s Disease (AD) is a progressive neurodegenerative disorder that develops unnoticed during several years prior to the onset of clinical symptomatology. The deterioration of delayed recall is one of the most significant predictive factors to define the progression of Mild Cognitive Impairment (MCI) to AD, and it has a strong relationship with medial temporal dysfunction. Identifying a reliable measurement of brain health and cognitive function is essential to mitigate the side effects of cognitive decline by promoting early intervention. The purpose of this study was to explore, in MCI patients and ‐healthy participants, how memory loss modifies the functional integrity of resting‐state brain activity, as measured with MEG. Method 118 MCI (aged from 58 to 87) and 261 healthy (aged from 41 to 82) participants were recruited from the Hospital Universitario San Carlos (Madrid, Spain). They all underwent an extensive neuropsychological evaluation, MRI, and MEG recordings. Results Delayed recall (DR) . The correlation analysis between functional connectivity (FC) and DR score showed a negative correlation, (rho = ‐0.208, p <0.001), between beta‐band FC and LTM performance in the occipital region, so that participants with higher FC showed lower memory performance. Furthermore, the correlation between LTM and beta FC‐st remained significant when looking at the MCI (rho = ‐0.236, p < 0.01) and healthy groups separately (rho = ‐0.207, p< 0.001). Short Term Memory (STM) . The STM was found to be associated, (rho = 0.175, p < 0.001), with increased occipital alpha‐band FC, indicating that those participants with the higher FC, the higher the memory performance. Interestingly, a separate analysis of both groups revealed that this correlation was present only in the healthy group (rho = 0.141, p <0.02). Conclusion A dual pattern of a respective decreased/increased beta/alpha FC in the occipital brain region appeared to be associated with memory performance in healthy and pathological aging.