Table 2.

Dopamine systems

Dopamine systems	Origin	Projections	Function
Nigrostriatal	SN (A9)	Striatum	Motricity
Mesocortical	VTA(A10)	Cortex	Emotionality
Mesolimbic	VTA(A10)	NAc	Reward and desire
Tuberoinfundibular	Arcuate Nucleus (A12)	Median Eminence	Regulation of prolactin release
Incertohypothalamic	Zona Incerta (A13) Periventricular region (A14)	Various hypothalamic nuclei, thalamus	Sexual arousal and copulation
Diencephalospinal	Hypothalamus (A11)	Spinal cord	Afferent stretch reflex, contraction of penile striated muscles

Central dopamine pathways. Within the CNS, three major dopamine pathways exist; the nigrostriatal, mesocortical/mesolimbic and tuberoinfundibular systems which influence motor function, mood, reward and neuropeptide release. There are two additional minor dopamine pathways; the incertohypothalamic and diencephalospinal systems which are believed to modulate elements of sexual behavior. SN = substantia nigra; VTA = ventral tegmental area; Nac = nucleus accumbens).