Neuromelanin contributes to locus coeruleus contrast in MRI scans

The locus coeruleus (LC) attention system is a target for understanding cognitive difficulties in children and older adults. Recent neuroimaging studies have suggested that LC can be structurally identified.  We now have direct evidence from an ex vivo imaging and histologic study that this contrast is impacted by the density of neuromelanin that normally accumulates in LC neurons with age (picture below: neuromelanin across histological sections corresponds to contrast in the MRI scan).  It is not clear that there is a direct correspondence between LC contrast, neuromelanin, and the number of healthy LC neurons, but the demonstration that neuromelanin contributes to LC contrast in MRI scans is a first step in  developing a biomarker that could be used to track disease and benefit from interventions.