Inverse Association of Locus Coeruleus <scp>MRI</scp> Integrity With Structural Volume and Its Impact on Individual's Inattentiveness

The locus coeruleus (LC) is a nucleus within the brainstem associated with physiological arousal and altered structure and function in the context of neurological conditions. Pathologies related to difficulties with attention have previously been associated with abnormalities in neurotransmitter production and sensitivity, suggesting the possibility of abnormality in neurotransmitter-producing neural regions. One such region is the LC, associated with norepinephrine production. To examine the possibility that LC alteration is associated with inattentive symptom reporting, regression analyses were performed using neuromelanin contrast ratios and volume in a sample of 141 individuals age-ranged from 8 to 54. Mediation modeling was subsequently performed to examine the relationship between neuromelanin contrast and volume in regard to inattentive behavior. We found that the structural integrity value of the LC, especially in the right hemisphere, showed a significant negative association with the level of the individual's inattentiveness score. LC volume was also significantly positively associated with inattention, and this finding was also lateralized to the right LC. Interestingly, an inverse association was found between structural integrity and volume. These findings support the relationship between LC and attention-related behavior through both neuromelanin-sensitive and structural imaging, with important implications for the association between regional structure and function.