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The Centre for Cognitive Ageing and Cognitive Epidemiology (CCACE) is a centre of excellence to advance research into how ageing affects cognition, and how mental ability in youth affects health and longevity.
Based at the University of Edinburgh and funded by the Medical Research Council (MRC), ESRC, BBSRC and EPSRC through the LLHW MRC's Lifelong Health and Wellbeing scheme, the Centre is led by Professor Ian Deary alongside 2 co-Directors, 6 Research Group Leaders, 10 core staff, 27 Research Members, and 20 Associate Members spread across three University of Edinburgh sites (George Square, New Royal Infirmary of Edinburgh, Western General Hospital). The Centre's scientists are focussing on three main areas of research:
- developing new methods to look at the brain and test how well it is working;
- studying whether there is a link between our cognitive abilities early and late in life; and
- whether the way our brains age is affected by our lifestyle as well as genetic, social, economic and psychological aspects of our lives (some of this research is being funded by Age UK’s Disconnected Mind project).
The Centre’s scientists want their findings to make a practical difference to people’s lives. This might be by identifying lifestyle changes that slow down cognitive decline or by developing new drugs that lessen the cognitive deterioration associated with dementia. It might be by developing tests that detect the onset of difficulties with skills like multi-tasking, which are important for independent living. A better understanding of age-related cognitive decline might lead to improved care environments for older people.
The group is interested in how the intelligence of children might affect them in later life. To investigate this, they are following the health of people who are now middle-aged or elderly but who had their cognitive abilities tested when they were children or young adults (for example, school pupils or army recruits). In studies of this kind, they analyse many people, sometimes more than a million. Thus, they are looking at appropriate groups of people in Scotland, England, Europe, and the USA. They have found that people with lower cognitive ability early in life seem to be at higher risk of conditions such as heart disease, cancer and mental illness as they get older. They are also investigating the genetic and environmental factors that might contribute to the link between cognitive ability and physical health. Early life influences might also be important, so they are looking at the mother's behaviour – if she breast feeds, smokes and drinks alcohol.
Human Cognitive Ageing
People differ greatly in the degree to which their brains decline with age. Some older people suffer only a minor decrease in mental agility while others go on to develop dementia. The Centre's researchers want to understand why cognitive decline occurs, and what makes some of us more susceptible than others. The Human Cognitive Ageing research group has two sub-groups
- Individual Differences; and
- Human Cognitive Neuroscience
The Individual Differences subgroup is interested in the factors that cause changes in our cognitive skills throughout our lives. In 1932 and 1947, all 11-year-olds in Scotland took a test at school called the Scottish Mental Survey. As part of the Disconnected Mind project, many of these people have been re-tested in old age to see how their cognitive skills have changed with time. These individuals have also provided information about their lifestyles and health and they have had brain scans and given blood from which the researchers can prepare DNA for genetic testing. By collaborating with the other groups at the Centre, this particular group will work out the social and biological influences which contribute to cognitive change.
The Human Cognitive Neuroscience subgroup is interested in mapping the changes in different cognitive skills that occur with age. They want to find out which cognitive functions – such as memory and multi-tasking skills – are strongest at different stages of our lives and which deteriorate most rapidly as we get older. They are developing sensitive tests for different cognitive skills. These will be used in healthy people of different ages to monitor the normal pattern of cognitive change, and in people with stroke or dementia to measure the severity of cognitive decline.
Stress, Hormones and Cognitive Ageing
Glucocorticoids are steroid hormones that regulate a variety of important processes in our bodies including glucose metabolism, the immune system and our response to stress. Normally, glucocorticoid levels are only raised for a short period of time. Prolonged exposure to high levels of glucocorticoid can have a number of harmful effects including high blood pressure, diabetes and cognitive impairment. A specific region of the brain called the hippocampus, which is important for long-term memory, is particularly sensitive to glucocorticoids. The goal of this group's research is to find out how and why elevated glucocorticoid levels have an adverse effect on brain structure and cognitive skills with age. With the help of volunteers from the Disconnected Mind project, researchers hope to discover how our genes, our brain cells and the balance of hormones in our bodies affect cognitive decline. The group will also be looking at animal models to help us understand how steroid hormones may affect cognitive ageing. Glucocorticoids are also important for foetal brain development and researchers are investigating how glucocorticoid levels in the womb might ‘programme’ the brain and affect cognitive ability later in life.
Animal Models of Cognitive Ageing and Neural Health
Most people experience a gradual decline in cognitive ability as they get older but certain illnesses such as dementia, stroke and long term exposure to stress-related hormones can cause more rapid and severe cognitive decline. This group wants to understand the relationship between the loss of cognitive ability that occurs in these diseases and normal age-related cognitive decline. Cognitive skills can be assessed in animals as well as people. Learning and memory can be tested in rats and mice using mazes in which food is hidden as a reward. In fact, rats and mice show age-related decline in cognitive skills just like humans. Some of the brain changes that occur in people with dementia or stroke can be copied in rats or mice through surgery or by altering their genes. These ‘animal models’ are extremely valuable because they allow researchers to compare the cognitive skills of treated and untreated (but otherwise identical) animals. They can also be used to test whether drugs have a positive effect on cognitive ability. Researchers are developing sensitive learning tests to compare age-related cognitive decline in treated and untreated animals. Brain structures can also be compared using mini-MRI machines specially designed to scan animals.
Human and Animal Brain Imaging
Scanning machines allow doctors to see inside the human body without the need for surgery. The detailed images they produce make it much easier to detect and diagnose disease. Scanners are also being used by scientists for research purposes. For example, MRI (Magnetic Resonance Imaging) gives very detailed and accurate images of the brain. This group can follow changes in the brain over time to improve our understanding of the causes of common brain disorders. Researchers are using MRI to investigate how the structure of the brain changes in older people, including the volunteers in the Disconnected Mind project. MRI can be used to look at brain structure and can identify the major bundles of nerve fibres (white matter) that connect one part of the brain to another. MRI can also be used to monitor brain activity and blood flow. They are developing image processing methods that are specifically designed to analyse the ageing brain. They are also using a special, high magnetic field MRI machine to look at the brains of rats and mice. Members of this group are also part of the SINAPSE Collaboration (Scottish Imaging Network: A Platform for Scientific Excellence) which shares resources and exchanges technical information with researchers at other scanning centres throughout Scotland.
Genetics and Statistics of Brain Ageing
How do our genes affect the way our cognitive skills decline with age? Researchers in this group are trying to answer this question using a fusion of genetics and statistics. They are looking at the pattern of genetic variants in the DNA of people who have had brain scans and/or cognitive skills tests, then analysing the data to see whether particular variants are more or less common in people with mild or severe decline in cognitive function. They are analysing genes that are already known to be involved in brain function. and are also searching through the whole genome to try and find genes that have not yet been linked to cognitive ability. The key to success in studies of this kind is recruiting large numbers of participants. The group has access to volunteer groups through projects such as Generation Scotland and Disconnected Mind. These types of genetic analysis generate very large amounts of data that require a lot of number crunching. Once analysed, the data can highlight specific genes that might be involved in cognitive ageing. This in turn can help reveal the biochemical pathways and biological processes that are important for cognitive function.