Dopaminergic pathways include the nigrostriatal, mesolimbic, and mesocortical tracts. The nigrostriatal tract makes most of the brain dopamine and forms a major part of the extrapyramidal motor system, projecting from the substantial nigra to the striatum.

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Dopaminergic pathways differ by where they start and where they go, which shapes what they affect. The nigrostriatal tract originates in the substantia nigra pars compacta and sends dopamine-rich signals to the striatum (caudate and putamen). This pathway is central to motor control and forms a major part of the extrapyramidal motor system, so it governs the smooth execution of movement. When this pathway deteriorates, as in Parkinson’s disease, movement becomes impaired, underscoring its key role in motor function. In contrast, the mesolimbic and mesocortical tracts originate in the ventral tegmental area and project to limbic structures and the prefrontal cortex, respectively, embedding dopamine in reward, motivation, and cognition. The tuberoinfundibular pathway runs from the hypothalamus to the pituitary and regulates prolactin secretion, a different, non-motor function.

Thus, the tract that accounts for the majority of brain dopamine and forms a major part of the extrapyramidal motor system by connecting the substantia nigra to the striatum is the nigrostriatal tract.