Abstract
There is growing evidence that integrity of the locus coeruleus - norepinephrine (LC-NE) system is important for later-life cognition. Less understood is how LC-NE system integrity relates to brain correlates of cognition, such as brain structure. Here, we assessed the relationship between cortical thickness and a measure of LC neuronal integrity in older (n = 229) and younger adults (n = 67). Using neuromelanin-sensitive MRI, we assessed LC integrity as a contrast between signal intensity of the LC and that of neighboring pontine reference tissue. The Freesurfer software suite was used to quantify cortical thickness. We found that LC contrast was positively related to cortical thickness in older but not younger adults, and this association was prominent in parietal, frontal, and occipital regions. Brain regions where LC contrast was related to cortical thickness include portions of the frontoparietal network and have been implicated in cognitive functions which are subject to strong noradrenergic modulation. These findings provide novel evidence for a link between LC integrity and brain structure in later adulthood.
Abbreviations
- BASE-II
- Berlin Aging Study-II
- LC
- locus coeruleus
- DPT
- dorsal pontine tegmentum
- FPN
- frontoparietal network
- MMSE
- Mini Mental State Examination
- MRI
- magnetic resonance imaging
- NE
- norepinephrine
- NM
- neuromelanin