41. GNMT is also expressed in various neurons presented in the cerebral cortex, hippocampus, substantia nigra and cerebellum. 42. Parkinson's symptoms occur when dopamine-producing neurons in the substantia nigra of the brain begin to die. 43. The largest and most important sources of dopamine in the vertebrate brain are the substantia nigra and ventral tegmental area. 44. In this model, the dopaminergic projections from the substantia nigra to the basal ganglia function as the prediction error. 45. The substantia nigra has a high quantity of dopaminergic neurons, which are nerve release the neurotransmitter known as dopamine. 46. As with dopaminergic neurons in the substantia nigra, neurons in the locus caeruleus tend to be melanin-pigmented. 47. In addition, TRPC4 mRNA is present in midbrain dopaminergic neurons in the ventral tegmental area and the substantia nigra. 48. Ventral tegmental area ( VTA ) and substantia nigra pars compacta ( SNc ) are part of the dopamine layer. 49. Other changes in the substantia nigra include increased expression of NMDA receptors in the substantia nigra, and reduced dysbindin expression. 50. Other changes in the substantia nigra include increased expression of NMDA receptors in the substantia nigra, and reduced dysbindin expression.
