Spontaneous blinking and brain health: Can blink‐related oscillations capture brain changes in aging?
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AbstractBackgroundBlink‐related oscillations (BROs) are recently discovered neurophysiological responses that follow spontaneous blinking, and represent environmental monitoring and awareness processes as the brain evaluates new visual information after eye reopening. BROs strongly activate the precuneus which is one of the earliest brain regions impacted by Alzheimer’s disease (AD) neuropathology, and as such may provide an important avenue for assessing and monitoring brain health in aging. In this study, we conducted the first investigation of BRO effects in normal aging to determine whether these responses can capture aging‐related brain changes.MethodThis research used data from the Cambridge Centre for Aging and Neuroscience (Cam‐CAN) repository, which comprises magnetocenphalography (MEG) and structural magnetic resonance imaging (MRI) from 700 healthy adults aged 18‐88. The MEG paradigm consists of a target detection task with simultaneous auditory and visual stimulation. MEG data were first denoised using independent component analysis, then BRO responses were derived by segmenting the cleaned data into 3s epochs time‐locked to spontaneous blinking. Participants were divided into 4 age groups comprising the youngest (18‐30), middle‐young (31‐50), middle‐old (51‐70), and oldest (71‐90), and analyses were performed using global field power (GFP) and minimum norm estimates to examine BRO effects at the sensor‐ and source‐levels, respectively.ResultResults showed that BRO responses were present in all age groups. GFP amplitude increased with age during intervals spanning post‐blink BRO peaks, but not the pre‐blink baseline (p<0.05). BROs also activated brain regions spanning the occipital, temporal, and parietal cortices in all age groups (p<0.05 FWE), with the extent of activation increasing with age. Moreover, the activation extent of precuneus and hippocampus regions showed inverted U‐shape with age, increasing towards the middle‐old group but decreasing in the oldest.ConclusionThese results demonstrate for the first time that BRO responses can capture brain changes in normal aging, with increased neural activation for processing blink‐related information as one ages. Results suggest that BROs may represent a simple yet powerful avenue for measuring aging‐related brain function changes, providing a potential tool for early detection of neurodegeneration – particularly with respect to the precuneus and hippocampus regions highly implicated in AD.
