Nigrostriatal pathway
It is one of the four major dopamine pathways in the brain, and is critical in the production of movement as part of a system called the basal ganglia motor loop.The pars compacta contains dopaminergic neurons from the A9 cell group that forms the nigrostriatal pathway that, by supplying dopamine to the striatum, relays information to the basal ganglia.The SNc is composed of a thin band of cells that overlies the SNr and is situated laterally to the A10 group of dopaminergic neurons in the ventral tegmental area (VTA) that forms the mesolimbic dopamine pathway.The SNc is easily visualized in human brain sections because the dopamine neurons contain a black pigment called neuromelanin which is known to accumulate with age.Dopamine cells in the lower layer (or ventral tier) lack this protein and are more vulnerable to the effects of neurotoxins (e.g. MPTP) that can cause Parkinson disease-like symptoms.[6][9] The axons from dopamine neurons emanate from a primary dendrite and project ipsilaterally (on the same side) via the medial forebrain bundle to the dorsal striatum.In primates and other mammals, it is divided by the anterior limb of a white matter tract called the internal capsule[13] into two parts: the caudate nucleus and the putamen.Approximately half of these MSNs contain dopamine D1 receptors and project directly to the substantia nigra to form the direct pathway of the basal ganglia, whereas the other half express dopamine D2 receptors that project indirectly to the substantia nigra via the globus pallidus and subthalamic nucleus to form the indirect pathway of the basal ganglia.[34] Levodopa-induced dyskinesias (LID) is a complication associated with long-term use of the Parkinson's treatment L-DOPA, characterized by involuntary movement and muscle contractions.
Anatomical terminologydopaminergic pathwaysubstantia nigrapars compactadorsal striatumcaudate nucleusputamendopamine pathwaysDopaminergicGABAergicneuronsParkinson's diseasehypokinesiatremorspostural imbalancemidbrainpars reticulatastriatumbasal gangliaventral tegmental areamesolimbic dopamine pathwayneuromelanincalbindinneurotoxinsdendritesmedial forebrain bundlestriosomepedunculopontine nucleusventral pallidumsubthalamic nucleusglobus pallidusamygdalathalamusforebrainwhite matterinternal capsuledopamine D1 receptorsdopamine D2 receptorscerebral cortexglutamatergichippocampusacetylcholinesterasedendritic spinesmesolimbicmesocorticaldirect pathway of movementindirect pathway of movementdirect pathwayindirect pathwaysubthalmic nucleusLevodopa-induced dyskinesiasL-DOPAschizophreniamesocortical pathwaymesolimbic pathwaytuberoinfundibular pathwayDopamineStutteringBibcodeNeuroNamesAcetylcholineNucleus basalis of MeynertNeocortexSeptal nucleiMedial septal nucleusFornixDopaminergic pathwaysPrefrontal corticesNucleus accumbensolfactory tubercleSubstantia nigra pars compactaInfundibular nucleusMedian eminenceNorepinephrineLocus coeruleusLateral tegmental fieldSerotonin pathwaysRaphe nucleiAnterior raphespinal tractLateral raphespinal tractAspartateClimbing fibersRostromedial tegmental nucleusGlycineRenshaw cellsGlutamatespinal cordneural tractsfasciculiPacinian corpuscleMeissner's corpusclePosterior columnGracile fasciculusCuneate fasciculusGracile nucleusCuneate nucleussensory decussationPosterior external arcuate fibersInternal arcuate fibersMedial lemniscusTrigeminal lemniscusPosterior limb of internal capsulePostcentral gyrusAnterolateralFree nerve endingA delta fiberAnterior white commissureLateralAnteriorSpinothalamic tractSpinal lemniscusPosterior parietal cortexSpinomesencephalic tractSuperior colliculusMidbrain tectumGroup C nerve fiberSpinoreticular tractReticular formationCingulate cortexPyramidalPrimary motor cortexDecussation of pyramidsCorticospinal tractNeuromuscular junctionExtrapyramidalGenu of internal capsule