locus
(lō'kŭs 
, lō'kē‵, lō'kī‵, lō'sī‵)
Plural: loci
[L. locus, a place]
- A spot or place.
- In genetics, the site of a gene on a chromosome.
Variant: locus caeruleus
Variant: locus ceruleus
A bluish reticular nucleus in the central gray area of the caudal midbrain and part of the reticular formation. Its output axons project widely and diffusely to all parts of the central nervous system. Signals from the locus coeruleus appear to enhance the overall attentiveness level of the brain. Neurons in this nucleus are noradrenergic.Variant: health locus of control
An individual's sense of mastery or control over events. Persons with an internal locus of control are more apt to believe that they can influence events, whereas those with an external locus of control tend to believe that events are dictated by fate. These respective orientations can influence a person's practice of health-related behaviors.