In vivo anatomical mapping of human locus coeruleus functional connectivity at 3 T MRI

Abstract

The locus coeruleus (LC) is involved in numerous crucial brain functions and several disorders like depression and Alzheimer's disease. Recently, the LC resting-state functional connectivity (rs-fc) has been investigated in functionalMRI by calculating the blood oxygen level–dependent (BOLD) response extracted using Montreal Neurological Institute (MNI) space masks. To corroborate these results, we aimed to investigate the LC rs-fc at native space by improving the identification of the LC location using a neuromelanin sensitive sequence. Twenty-five healthy male participants (mean age 24.8 ± 4.2) were examined in a SiemensMAGNETOMPrisma 3 TMRT applying a neuromelanin sensitive T1TSE sequence and functional MRI. We compared the rs-fc of LC calculated by aMNIbased approachwith extraction of the BOLD signal at the exact individual location of the LC after applying CompCor and field map correction. As a measure of advance, amarked increase of regional homogeneity (ReHo) of time serieswithin LC could be achieved with the subject-specific approach. Furthermore, themethods differed in the rs-fc to the right temporoparietal junction, which showed stronger connectivity to the LC in the MNIbased method. Nevertheless, both methods comparably revealed LC rs-fc to multiple brain regions including ACC, bilateral thalamus, and cerebellum. Our results are relevant for further research assessing and interpreting LC function, especially in patient populations examined at 3 TMRI.