A suite of videos explores a major BBSRC programme to study ageing and cognition in healthy adults.
- Part #2: MRI brain imaging
- Part #3: MEG brain waves
- Part #4: Motor learning experiment
- Part #5: Hitchcock emotional movie response
It is said that death and taxes are the only certainties in life. Ageing is another aspect of living common to every person whether old or young – but what's different is how our brains and cognitive abilities change as we grow older.
There are marked differences between individual cognitive abilities with increasing age. Some people's minds remain sharp and intact well into their 80s and 90s, whereas others can slide into cognitive decline from their early 50s. Why such a divergence? And then there are the people struck by the spectrum of conditions known as Alzheimer's disease; why do some people succumb to such a slow and debilitating fate, while others live longer, healthier lives?
A major £5M grant from BBSRC has established a new team called the Cambridge Centre for Ageing and Neuroscience (Cam-CAN) that seeks answers to these questions. By studying the brain and its cognitive functions using advanced brain imaging techniques and cognitive experiments, the team of researchers, based at the University of Cambridge and the MRC Cognition and Brain Sciences Unit, hope to unravel the mechanisms and processes of healthy brain ageing.
"We are hoping that it will reveal the ways in which the brain's functionality can adapt to the age-related changes that take place in its structure (the white and grey matter) so as to maintain cognitive functions," says Cam-CAN Director Professor Lorraine Tyler from the University of Cambridge. "In doing so, we hope to be able to develop predictive models of healthy ageing so that, eventually, we will be able to determine a person's 'healthy aging the trajectory' when they are quite young."
This way, the biomarkers for health can be compared with the biomarkers from disease states, and interventions designed and implemented that in the future might restore the balance and well-being that every person wants.
And it's not just about old people. The Cam-CAN project is looking at the abilities of spritely 18-year-olds too; in fact its full cohort of 3000 participants spans the full adult range of 18-88. This is because recent research suggests that the brain changes throughout our lifespan – not just when we are older. Hence, studying healthy rather than diseased states in all ages constitutes a novel and ambitious approach that could change our perspective of ageing processes, and reveal why abilities such as language are retained while others such as memory are lost.
A new cohort
Beginning in October 2010, a significant part of the first two years have been spent building up the population-representative cohort of participants, a complex and resource-intensive process that involved sending out tens of thousands of letters and interviewing thousands of people in their homes to get a cohort for more detailed brain imaging and cognitive testing. The team also focused on developing new statistical methods for combining neural and cognitive measures, including measures of brain activity from fMRI (functional magnetic resonance imaging) and MEG (magneto-encephalography).
Tyler and her colleagues are enthusiastic about the study cohort they have established, which is also a first for sole BBSRC funding. She says the uniqueness of the Cam-CAN project is the combination of its properties. "We have a great deal of different kinds of information in the same population. The depth and breadth of the neural and cognitive measures as well as genetic data on such a large number of people in a population-representative cohort is exceptional."
From the starting cohort of 3000, the field is narrowed down to 700 suitable individuals – 100 people per decade from 18-88 – on which MRI and MEG data are obtained, as well as various cognitive tests covering emotion, memory, attention and language. 280 participants are then selected for a further battery of studies, including motor skills. "Each test is designed by an expert in the field," Tyler explains.
The researchers hope that the results will help reveal why some cognitive functions, such as memory, suffer with increasing age whereas others, notably understanding spoken language, appear relatively unaffected. "The brain undergoes considerable changes across the adult lifespan, yet appears to retain some ability to reorganise or compensate for such changes," says Cam-CAN Assistant Director Professor Rik Henson. "This offers the hope that we can intervene in future to better maintain cognitive function into old age."
Central to the Cam-CAN project is the use of brain imaging methods. To this end, the team are employing both fMRI and MEG scanning techniques, and merging the two to obtain a more complete picture of what is happening in the brain. This is because fMRI relies on blood supply, which usually declines age, making it difficult to differentiate changes in neural activity from age-related changes in just the vasculature that supplies blood. "This is why we also use a technique called MEG, which measures neural activity more directly, offering a clearer window on functional changes (though with less spatial precision)," says Henson. "A complete picture of the ageing brain can only be obtained by combining all these different types of neuroimaging data."
For example, the team has examined patterns of connectivity using fMRI and MEG while people are resting with their eyes closed. Henson says they see significant changes in the properties of networks of functionally connected regions from the youngest to oldest volunteers. "The younger brains show a greater clustering of connections, which suggests that local brain connectivity becomes fragmented as people grow older – and the MEG data suggest this is not simply a consequence of vascular changes with age," he says.