The Cognition, Brain, and Aging project (COBRA) is a longitudinal study that involves scientists from ARC, Umeå University, and the Max Planck Institute for Human Development in Berlin. COBRA follows around 180 persons who were between 63 and 67 years at baseline across nine years, with three measurement occasions. Multiple brain measures are assessed at each interval using PET and MRI (i.e., dopamine D2 receptors, markers of grey- and white-matter integrity, and functional networks). Cognition is assessed using measures of working memory, episodic memory, and speed, and information on lifestyle factors is collected through administered questionnaires.
The degree of average age-related change in DA availability, grey matter, and white matter remains unclear because of the paucity of longitudinal data. The shared and unique contributions of changes in DA, grey matter, and white matter to changes in cognitive performance in old age are unknown. It is also unknown which of the candidate neural correlates (DA, grey matter, or white matter) of cognitive decline first displays signs of change in old age. Our main hypothesis is that age-related DA changes precede changes in the other brain indices assessed and serve as the most powerful antecedent of age-related cognitive changes. Finally, the lifestyle factors associated with changes in the brain parameters assessed are largely unknown. New knowledge in these areas is critical because identifying key lifestyle factors that modify brain and cognition in old age will inform the focus of prevention strategies.