Systems Cognitive Neuroscience of Healthy Ageing: Population-Representative Studies of Functional Plasticity and Neural Change

As greater numbers of us are living longer, it is increasingly important to understand how we can age healthily. Growing older involves dramatic changes to all aspects of our lives, but one of the most important concerns is our mental or 'cognitive' health. This research focuses on the cognitive abilities that enable us to function in the world, including memory, attention, emotion, language, action. We aim to understand how individuals can best retain these abilities into old age. Addressing this issue requires us to understand how brain structure and function support cognitive performance. Recent developments in neuroimaging technology show that as we age there is widespread loss of brain tissue in regions important for everyday cognition. Much research has focused on this tissue loss, and its role in cognitive decline in later life. However, other findings paint a more positive picture. While some cognitive abilities decline with normal ageing, many are spared. Moreover, cognitive decline doesn't occur abruptly at a pensionable age: cognitive abilities follow different trajectories across the lifespan, some remaining stable into our 80s, and some beginning to decline even in our 30s. Underpinning this complex pattern of spared and impaired cognition are complex interactions between neural structure and activity. A growing number of studies show that the brain responds flexibly to tissue loss, recruiting other brain regions to support neural function. This functional plasticity is possible because cognitive abilities, like memory or attention, are not underpinned by single brain regions, but by networks of regions. Successful ageing is therefore characterised by successful functional plasticity. Although ageing is often stereotyped as a time of mental restriction and inflexibility, cognitive neuroscience reveals that across the adult lifespan individuals make flexible use of available resources, including recruiting other regions and cognitive processes when necessary. Research Aims and Objectives Our aim is to identify what determines successful flexibility. This requires us to sample across the adult lifespan, measuring different aspects of neural structure and activity, and of cognitive performance. We will study a cohort of 700 participants aged 18 to 88, who will have a structural brain scan and perform key cognitive tests. Some members of this cohort will also participate in functional neuroimaging experiments to measure brain activity during cognitive tasks. We will ask (1) Is functional plasticity maintained across the lifespan and does it vary across cognitive abilities? (2) Are the distributed neural networks that support different cognitive abilities preserved in ageing? (3) Does the preservation of different cognitive functions vary, given the variability of neural change in different brain regions? Potential applications and benefits Our research will generate a unique resource of neuroimaging and cognitive measures about change across the adult lifespan, generating important benefits for academic researchers, the older community, and wider society. It will provide major contributions to ageing research, and provide a 'virtual brain and behaviour bank' acting as a continuing international resource for future research. Our focus on healthy ageing will be educationally important for all older adults. Few studies of ageing focus on healthy ageing, and the prevalent view of ageing is of deficit and ill-health. Our focus is on what characterizes older adults with preserved performance, a perspective with huge implications for how society views the ageing process. Moreover, our detailed analysis of neural and cognitive flexibility will help identify the conditions under which older adults may be aided by interventions. Finally, because our findings will help specify normal age-related deficits, they will show how normal ageing differs from pathological ageing in conditions such as Alzheimer's Disease.