Using MRI, I have recently observed, in collaboration with a colleague here at Oxford and our collaborator in Birmingham, that older individuals with greater resilience to cognitive decline exhibit less structural loss in the right fronto-parietal regions of the brain (Shalev, Brosnan, & Chechlacz, 2020 Cerebral Cortex Communications), and show altered (better) white matter structural properties (Brosnan et al., 2022, Brain Communications). Critical, older adults exposed to more cognitively and socially enriched environments showed better markers of brain, and subsequently cognitive health. We are excited by this work as it highlights a specific structural target for neurorehabilitation interventions to prevent and redress age-related cognitive deficits.
In addition I have been using neurophysiology (electroencephalography (EEG) and magnetoencephalography (MEG)) to understand the precise neurophysiological mechanisms underpinning variability in neurocognitive health in older adults. These results were well received at a recent conference (MEG UK) and we are currently preparing these for publication.
Emerging EEG work from an international collaboration between us here at Oxford (grant holder Méadhbh Brosnan and mentor Anna C. (Kia) Nobre), researchers at Monash University in Australia (PI Mark Bellgrove), and Trinity College in Dublin (Redmond O’Connell), highlights the particular relevance of a distinct neurophysiological signature (the centro-parietal positivity marker of sensory evidence accumulation) for indexing neurocognitive health in the ageing brain (Brosnan et al., under invited revision at Journal of Neuroscience,
https://www.biorxiv.org/content/10.1101/2021.10.28.466233v1.full.pdf(odnośnik otworzy się w nowym oknie)).
We are currently exploring whether a common oscillatory marker varies according to cognitive resilience using MEG data acquired using a ‘retro-cue’ working memory task. More specifically with this approach, we are investigating whether the speed at which an older adult can orientate their attention to items held in working memory (i) accounts for variability in longitudinal decline and (ii) difers according to oscillatory signatures in prefrontal cortex.
Finally, patients recovering from COVID-19 are experiencing persistent and often debilitating levels of fatigue, sustained attention and arousal difficulties (the latter which is often self-reported ‘brain fog’). My previous research, conducted as part of Marie Curie training network (the INDIREA project), focused on understanding the neurobiological basis of these symptoms in stroke survivors and designing novel intervention approaches to alleviate these deficits. Here at Oxford, in collaboration with the ‘C-MORE’ multi-organ study of COVID, I am applying this experience to investigate the neural basis of these symptoms in COVID survivors. We (Kia Nobre, Tom Marshall and I) have designed a novel MEG task to better understand the impact of covid on the brain, over and above the damage observed in other organs (most notably the lungs and heart). We have recently published some work developing the methods on this task to measure attention difficulties in patients who have experience stroke (Brosnan et al., 2022, Journal of the International Neuropsychological Society). In addition, to ensure widespread translational utility of this task, we have developed an online version of the task which is sensitive to deficits in attention across the lifespan. We are currently in conversation with industry parterns about the possibility of incorporating this into a commercially available product for better understanding cognitive health.
