GRK 2413/2-Project D1: Aberrant memory-related network activity and connectivity in hippocampal-posterior cortical circuits with ageing

Some of the earliest age-related changes in brain activity and functional connectivity occur within the hippocampus and posteromedial cortex. These regions are strongly interconnected and both are involved in a variety of cognitive tasks that are compromised during ageing, including episodic memory. Our aim is to better understand the spatio-temporal dynamics and implications of these age- and memory-related functional changes.
Functional magnetic resonance imaging (fMRI) studies in cognitively normal older adults have found increased fMRI task-related activity in the hippocampus as well as posterior-midline regions relative to younger adults. While this „hyperactivation” has been related to poorer memory performance in older adults evidence also suggest that it may represent functional compensation. However, the picture is complex, with studies reporting both poorer memory performance associated with higher and lower intrinsic functional connectivity. Furthermore, the relationship between changes in activity and functional connectivity and how this relates to memory performance may be further moderated by early tau pathology in ageing . Thus, future studies in the cognitively normal elderly should also account for hidden Alzheimer’s pathology.
A systematic investigation into the task-related changes in activity and network connectivity in relation to this aberrant fMRI activity across hippocampal-posterior cortical regions during critical stages of healthy ageing (age ranges 60-80 years) has not been undertaken in humans. In addition, our aim is to elucidate the relationship between alterations in activity and functional connectivity in these regions with episodic memory performance in normal ageing.
We use multimodal neuroimaging methods including fMRI and positron emission tomography (PET) as well as cognitive testing and demographic data to address those open questions.