The nucleus involved in Alzheimer's disease is -
Alzheimer disease 

Alzheimer disease (AD) is the most common cause of dementia in the elderly.
Alzheimer's disease is associated with a decrease in cerebral cortical levels of Acetylcholine.
Reduction of Acetylcholine is related to degeneration of cholinergic neurons that project to many areas of cortex.
This degeneration occurs in the nucleus basalis of Mayernet.
Basal nucleus of Mayernet
Raphe nucleus
Superior salivary nucleus
Basal lobe of cerebellum