Located below the shell nucleus in the transition between the midbrain and end brain (basal forebrain = the basal forebrain) and there in an area called substantia innominata (a possible Swedish name could be "the area without a name"). The nerve cells produce acetylcholine which, via a wide outflow of nerve fibers, is distributed to virtually all parts of the cerebral cortex, which in this way can be said to be irrigated with acetylcholine!
There appears to be a link between degeneration in Meynert's basal nucleus and the onset of Alzheimer's disease.