Cognitive ageing is a developmental process involving the interaction of lifelong cognitive experience and gradual neural change, resulting in a varied landscape of age-related cognitive declines and age-related adaptations that help preserve cognitive function. Research on cognitive ageing at the CSLB involves both new experiments developed within the lab, and participation in the Cambridge Centre for Ageing and Neuroscience (Cam-CAN; www.cam-can.org), a large-scale collaboration headed by Prof. Tyler and examining:
Language production across the lifespan
Specific aspects of language production are affected by normal ageing, including word finding. Word finding failures are a common source of complaint and concern for older adults because of their association with "forgetfulness" and senility. However, our ongoing research examines the specific cognitive and neural underpinnings of word retrieval problems associated with normal ageing; this includes identifying what aspects of language production are affected, the relationship between word finding and neural structure and function, and what characterises older adults with better and worse performance.
Read more about this project here.
Language comprehension: the role of task effects in designing ageing studies
It is widely assumed that cognitive functions decline with age and that these decrements are associated with age-related changes in patterns of functional activity. However, these studies typically use tasks which may not be orthogonal to the cognitive function being investigated, raising the possibility that the observed age-related functional changes may be due to task demands and not to core cognitive functions themselves. One project in our lab sought to test this hypothesis by scanning healthy participants while they listened to sentences, either naturalistically (no task) or while making a judgement (task). The language network (MTG, LIFG) activated during both no task and task conditions, but during the task older adults expressed this network less reliably. Moreover, this age effect during the task was accompanied by the activation of other task-specific networks. This project suggests that we may be overestimating age effects on core cognitive processes because of the widespread use of tasks that introduce additional demands.
Language comprehension: age-related functional reorganisation
In normal ageing, most measures of language comprehension are preserved. Recent evidence from neuroimaging suggests that preserved cognitive function in the context of age-related neural changes may reflect compensatory mechanisms. However, the existing sparse evidence is largely focused on functions associated with the frontal cortex, leaving open the question of how wider age-related brain changes relate to compensation. We evaluated relationships between age-related neural and functional changes in the context of preserved cognitive function by combining measures of structure, function, and cognitive performance during spoken language comprehension using a paradigm that does not involve an explicit task. We used a graph theoretical approach to derive cognitive activation-related functional magnetic resonance imaging networks. Correlating network properties with age, neuroanatomical variations, and behavioural data, we found that decreased gray matter integrity was associated with decreased connectivity within key language regions but increased overall functional connectivity. However, this network reorganization was less efficient, suggesting that engagement of a more distributed network in ageing might be triggered by reduced connectivity within specialized networks.
Read more about this project here.
The Cam-CAN project
As the population gets older an important issue for research is how to support healthy cognitive ageing. Although much research on cognition and ageing focuses on declines in neural integrity and cognitive ability, the recent burgeoning of functional neuroimaging studies has pointed to evidence for neural and cognitive flexibility across the lifespan. The Cambridge Centre for Ageing and Neuroscience (Cam-CAN) builds on this research to examine lifelong cognitive development by integrating measures of cognition with measures of neural structure and function. Language tasks developed at CSLB contribute to the range of cognitive measures currently being assessed.
Find out about Cam-CAN and our recent findings here: www.cam-can.com.