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.

LC_neuromelaninLC_neuromelanin

Cingulo-opercular Activity Provides Word Recognition Benefit

 

Recognizing speech in challenging listening conditions often produces increased activity in frontal cortex, particularly in cingulo-opercular regions, but the significance of this activity has been unclear. This network of frontal cortex is thought to monitor performance and signal when cognitive resources are required to ensure successful performance. Findings from earlier visuospatial studies indicated that […]

Changes in the Brain that Occur with Hearing Loss

Age-related hearing loss occurs for just about everyone. We wondered about the potential impact of hearing loss on brain structure because speech recognition can be difficult even after correcting for poor hearing thresholds. In a sample of 49 older adults, we observed that high frequency hearing loss was associated with lower gray matter volume in […]

Missingness in fMRI Studies: Multiple Imputation

Limited imaging coverage of the brain and susceptibility artifact contributes to missing data in functional imaging studies. Multiple imputation is one solution for dealing with missing data. We demonstrate in a recent Neuroimage manuscript the considerable benefit of using multiple imputation in functional imaging studies. There was a 35% increase in the number of voxels […]