Dopaminergic system

The dopaminergic system has two seperate paths:

Nigrostratial pathways (orange in pic)
Active in maintaining normal motor behaviour

Produced in:
Substantia nigra

Distributed to:
Caudate nucleus

Problems:
Loss of DA is related to muscle rigidity and dyskinesia in Parkinson's disease.

Mesolimbic pathways (purple in pic)
Responsible for feelings of reward and pleasure, thought to be most influenced by drugs and addictions.

Produced in:
Ventral tegmentum

Distributed to:
Prefrontal cortex, cerebellum, striatum (basal ganglia).

Problems:
Increases in DA may be related to schizophrenia, and decreases to deficits of attention.